Tesis sobre el tema "Hemodynamic monitoring"

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2002.
Includes bibliographical references (leaves 89-91).
Multi-channel Blind System Identification (MBSI) is a technique for estimating both an unknown input and unknown channel dynamics from simultaneous output measurements at different channels through which the input signal propagates. It is a powerful tool particularly for the identification and estimation of dynamical systems in which a sensor, for measuring the input, is difficult to place. All of the existing MBSI algorithms, however, are not applicable to multi-channel systems sharing common dynamics among the channels, since these algorithms, by nature, exploit "differences" among the multiple channel dynamics. This requirement renders the MBSI algorithms useless in systems that have both a lumped-parameter nature and a distributed nature; all channels in a system of this type share poles dictated by the lumped-parameter dynamics. To overcome this difficulty, this thesis investigates a new approach, Intermediate Input Identification (IIID). This thesis proves that the distinct dynamics in each channel can be identified up to a scalar factor even when common dynamics are present. Based on this discovery, the MBSI problem is reformulated and an intermediate input is introduced, which integrates the original system input and the common dynamics shared by all the channels. The two-step IIID approach is developed to solve the problem: first, the distinct dynamics are identified from the outputs; second, the common dynamics are identified from the intermediate input by exploiting the zero-input response of the system. The identifiability conditions are thoroughly investigated. The sufficient and necessary conditions and the relationship between the linear-complexity condition of the original input and that of the intermediate input are derived in this thesis.
(cont.) This thesis also develops a central hemodynamic monitoring scheme based on IIID. The similarities between the structure of a digital wireless communication system and that of the cardiovascular system are explained. The input, the common dynamics and the distinct dynamics in the cardiovascular multi-channel system are derived based on the determinants of arterial blood pressure. Analysis of the data from a cardiovascular simulator and animal experiments verify the validity of this scheme. The positive results demonstrate that the IIID approach could open up the possibility for noninvasive central hemodynamic monitoring, which could significantly reduce the risks to which patients are exposed.
by Yi Zhang.
Ph.D.

Cardiac output (CO) defines the blood flow arriving from the heart to the different organs in the body and it is thus a primary determinant of global 02 transport. Cardiac output has traditionally been measured using invasive methods, whose risk sometimes exceeds the advantages of a cardiac output monitoring. In this context, the minimization of risk in new noninvasive technologies for CO monitoring could translate into major advantages for clinicians, hospitals and patients: ease of usage and availability, reduced recovery time, and improved patient outcome. Impedance Cardiography (ICG) is a promising noninvasive technology for cardiac output monitoring but available information on the ICG signals is more scare than other physiological signals such as the electrocardiogram (ECG). The present Doctoral Thesis contributes to the development of signal treatment techniques for the ICG in order to create an innovative hemodynamic monitor. First, an extensive literature review is provided regarding the basics of the clinical background in which cardiac output monitoring is used and concerning the state of the art of cardiac output monitors on the market. This Doctoral Thesis has produced a considerable amount of clinical data which is also explained in detail. These clinical data are also useful to complement the theoretical explanation of patient indices such as heart rate variability, blood flow and blood pressure. In addition, a new method to create synthetic biomedical signals with known time-frequency characteristics is introduced. One of the first analysis in this Doctoral Thesis studies the time difference between peak points of the heart beats in the ECG and the ICG: the RC segment. This RC segment is a measure of the time delay between electrical and mechanical activity of the heart. The relationship of the RC segment with blood pressure and heart interval is analyzed. The concordance of beat durations of both the electrocardiogram and the impedance cardiogram is one of the key results to develop new artefact detection algorithms and the RC could also have an impact in describing the hemodynamics of a patient. Time-frequency distributions (TFDs) are also used to characterize how the frequency content in impedance cardiography signals change with time. Since TFDs are calculated using concrete kernels, a new method to select the best kernel by using synthetic signals is presented. Optimized TFDs of ICG signals are then calculated to extract severa! features which are used to discriminate between different anesthesia states in patients undergoing surgery. TFD-derived features are also used to describe the whole surgical operations. Relationships between TFD-derived features are analyzed and prediction models for cardiac output are designed. These prediction models prove that the TFD-derived features are related to the patients' cardiac output. Finally, a validation study for the qCO monitor is presented. The qCO monitor has been designed using sorne of the techniques which are consequence of this Doctoral Thesis. The main outputs of this work have been protected with a patent which has already been filed. As a conclusion, this Doctoral Thesis has produced a considerable amount of clinical data and a variety of analysis and processing techniques of impedance cardiography signals which have been included into commercial medical devices already available on the market.
El gasto cardíaco (GC) define el flujo de sangre que llega desde el corazón a los distintos órganos del cuerpo y es, por tanto, un determinante primario del transporte global de oxígeno. Se ha medido tradicionalmente usando métodos invasivos cuyos riesgos excedían en ocasiones las ventajas de su monitorización. En este contexto, la minimización del riesgo de la monitorización del gasto cardíaco en nuevas tecnologías no invasivas podría traducirse en mayores ventajas para médicos, hospitales y pacientes: facilidad de uso, disponibilidad del equipamiento y menor tiempo de recuperación y mejores resultados en el paciente. La impedancio-cardiografía o cardiografía de impedancia (ICG} es una prometedora tecnología no invasiva para la monitorización del gasto cardíaco. Sin embargo, la información disponible sobre las señales de ICG es más escasa que otras señales fisiológicas como el electrocardiograma (ECG). La presente Tesis Doctoral contribuye al desarrollo de técnicas de tratamiento de señal de ICG para así crear un monitor hemodinámico innovador. En primer lugar, se proporciona una extensa revisión bibliográfica sobre los aspectos básicos del contexto clínico en el que se utiliza la monitorización del gasto cardíaco así como sobre el estado del arte de los monitores de gasto cardíaco que existen en el mercado. Esta Tesis Doctoral ha producido una considerable cantidad de datos clínicos que también se explican en detalle. Dichos datos clínicos también son útiles para complementar las explicaciones teóricas de los índices de paciente de variabilidad cardíaca y el flujo y la presión sanguíneos. Además, se presenta un nuevo método de creación de señales sintéticas biomédicas con características de tiempo-frecuencia conocidas. Uno de los primeros análisis de esta Tesis Doctoral estudia la diferencia temporal entre los picos de los latidos cardíacos del ECG y del ICG: el segmento RC. Este segmento RC es una medida del retardo temporal entre la actividad eléctrica y mecánica del corazón. Se analiza la relación del segmento RC con la presión arterial y el intervalo cardíaco. La concordancia entre la duración de los latidos del ECG y del ICG es uno de los resultados claves para desarrollar nuevos algoritmos de detección de artefactos y el segmento RC también podría ser relevante en la descripción de la hemodinámica de los pacientes. Las distribuciones de tiempo-frecuencia (TFD, por sus siglas en inglés) se utilizan para caracterizar cómo el contenido de las señales de impedancia cardiográfica cambia con el tiempo. Dado que las TFDs deben calcularse usando núcleos (kernels, en inglés) concretos, se presenta un nuevo método para seleccionar el mejor núcleo mediante el uso de señales sintéticas. Las TFDs de ICG optimizadas se calculan para extraer distintas características que son usadas para discriminar entre los diferentes estados de anestesia en pacientes sometidos a procesos quirúrgicos. Las características derivadas de las distribuciones de tiempo-frecuencia también son utilizadas para describir las operaciones quirúrgicas durante toda su extensión temporal. La relación entre dichas características son analizadas y se proponen distintos modelos de predicción para el gasto cardíaco. Estos modelos de predicción demuestran que las características derivadas de las distribuciones tiempo-frecuencia de señales de ICG están relacionadas con el gasto cardíaco de los pacientes. Finalmente, se presenta un estudio de validación del monitor qCO, diseñado con alguna de las técnicas que son consecuencia de esta Tesis Doctoral. Las principales conclusiones de este trabajo han sido protegidas con una patente que ya ha sido registrada. Como conclusión, esta Tesis Doctoral ha producido una considerable cantidad de datos clínicos y una variedad de técnicas de procesado y análisis de señales de cardiografía de impedancia que han sido incluidas en dispositivos biomédicos disponibles en el mercado

Volume expansion is the first-line treatment for acute circulatory failure in almost all cases. However, its inconsistent effectiveness and its side effects make it necessary to predict the effects before undertaking it. Several tests have been developed to detect this state of preload dependence, and we are interested in refining some of them and improve their use. The end expiratory occlusion (EEXPO) test consists in transiently stopping mechanical ventilation at end expiration to increase venous return and, thus, cardiac preload. In preload responder patients it is expected to increase cardiac output. We have gathered an amount of information from the existing literature, showing that its ability of detecting fluid responsiveness is very high, through a systematic review and meta-analysis. The effects of this test must be assessed on cardiac output, and several methods have already been described for this. Bioreactance is a completely non invasive technique to measure cardiac output, which has been demonstrated to be reliable in detecting preload responsiveness through a passive leg raising (PLR) maneuver. Nevertheless, its role in detecting a positive EEXPO test was never investigated. In the main study of this PhD project, we show that the current available commercial version of the bioreactance device is not suitable for this purpose, due to its very long averaging and refreshing times (24 and 4 seconds, respectively). However, when we used a research version of the device, which allowed us to reduce both intervals (8 and 1 second for averaging and refreshing times, respectively), bioreactance proved to be a reliable method to detect preload responsiveness through the EEXPO test. We have also described an original and reliable method for measuring the effects of both PLR and EEXPO tests, which consists of measuring the perfusion index (PI), the ratio between the pulsatile and the non-pulsatile portion of the pulse oxygen saturation signal. Although the signal could not be collected stably in all patients, changes in this index during passive leg raising were able to measure the effects of the PLR test and predict the response to volume expansion. Similarly, Pl measurements could identify a positive EEXPO test, even though their changes were of lower amplitude compared to those of a PLR test. Our results open up the possibility of measuring the effects of these tests of preload responsiveness using non-invasive tools. This could prompt their use outside the intensive care unit, such as in the emergency department, where tracking changes of cardiac output during the first hours of the management of acute circulatory failure could lead to a more rational use of fluid administration.

Cardiovascular disease is a large problem in the intensive care unit (ICU) due to its high prevalence in modern society. In the ICU, intensive monitoring is required to help diagnose cardiac and circulatory dysfunction. However, complex interactions between the patient, disease, and treatment can hide the underlying disorder. As a result, clinical staff must often rely on their skill, intuition, and experience to choose therapy, increasing variability in care and patient outcome. To simplify this clinical scenario, model-based methods have been created to track subject-specific disease and treatment dependent changes in patient condition, using only clinically available measurements. The approach has been tested in two pig studies on acute pulmonary embolism and septic shock and in a human study on surgical recovery from mitral valve replacement. The model-based method was able to track known pathophysiological changes in the subjects and identified key determinants of cardiovascular health such as cardiac preload, afterload, and contractility. These metrics, which can be otherwise difficult to determine clinically, can be used to help provide targets for goal-directed therapies to help provide deliver the optimal level of therapy to the patient. Hence, this model-based approach provides a feasible and potentially practical means of improving patient care in the ICU.

Orientador: Paulo Sérgio Patto dos Santos
Resumo: Objetivou-se avaliar os efeitos hemodinâmicos, hemogasométricos e sedativos da associação de xilazina e nalbufina em equinos hígidos. Foram utilizados 7 equinos adultos (385 ± 82kg), de ambos os sexos, com idade média de 7 ± 3 anos. Após a administração de bolus sequenciais de xilazina (0,8 mg/kg) e nalbufina (0,025 mg/kg), pela via intravenosa (IV), iniciou-se a infusão contínua de xilazina (0,7 mg/kg/hora) e nalbufina (0,03 mg/kg/hora). As variáveis FC, PAS, PAD, PAM, DC, PVC, PAPM, IS, IC, IRVS, FR, pH, PaO2, PaCO2, HCO3-, BE, temperatura corporal, sedação, ataxia e motilidade intestinal foram avaliadas antes do início da administração dos fármacos (Basal) e a cada vinte minutos após o início da infusão contínua até 80 minutos (T20, T40 e T60 e T80). Houve redução da FC, IC, FR e aumento do IRVS e da PaCO2 após o início da infusão contínua dos fármacos. Com os resultados obtidos é possível concluir que a associação de xilazina e nalbufina, nas doses empregadas neste estudo, promoveu sedação e manteve a motilidade reduzida, sem causar alterações clinicamente significativas nos parâmetros hemodinâmicos e hemogasométricos.
Abstract: The aim of this study was to evaluate the hemodynamic, hemogasometric and sedative effects of xylazine and nalbuphine in healthy horses. Seven adult horses (385 ± 82 kg), with a mean age of 7 ± 3 years, were used. Administration of sequential doses of xylazine (0.8 mg kg-1) and nalbuphine (0.025 mg kg-1), both intravenous (IV), continuous rate infusion of xylazine (0.7 mg kg-1 hour-1) and nalbuphine (0.03 mg kg-1 hour-1). The variables HR, RR SAP, DAP, MAP, CO, CVP, MPAP, SI, CI, SVRI RR pH, PaO2, PaCO2, HCO3-, BE, body temperature, sedation, ataxia and motility were taken immediately before the administration of the drugs (Basal) and then at 20-minute intervals during 80 minutes (T20, T40, T60 and T80). Reduction of HR, CI, respiratory rate (RR) and increase of ISVR and PaCO2 were observed after the administration of xylazine and nalburphine combination. The results allow us to conclude that the xylazine and nalbuphine association, at the doses used in this study, promoted sedation and maintenance of motility reduction without causing clinically significant changes in hemodynamic and hemogasometric parameters.
Mestre

Thesis (MMed (Obstetrics and Gynaecology))--University of Stellenbosch, 2010.
ENGLISH ABSTRACT: OBJECTIVE: The aim of this study was to compare the accuracy of non-invasive blood pressure measurements, using automated and manual devices, against invasive intra-arterial blood pressure measurements in patients with pre-eclampsia, during a hypertensive blood pressure peak. STUDY DESIGN: In this prospective study, women admitted to the Obstetrics Critical Care Unit, with confirmed pre-eclampsia and acute severe hypertension, who had an intra-arterial line in situ, were asked to participate. During an intra-arterial blood pressure peak, both an automated oscillometric and a blinded manual aneroid sphygmomanometric blood pressure was recorded. These two methods of blood pressure measurements were compared to intra-arterial blood pressure measurements. The accuracy of a mean arterial pressure (MAP) ≥ 125mmHg in detecting a systolic blood pressure (SBP) ≥ 160mmHg, using all three methods, was also determined. RESULTS: There was poor correlation between intra-arterial SBP and automated and manual SBP (r = 0.34, p < 0.01; r = 0.41, p < 0.01 respectively). The mean differences between automated and manual SBP compared to the intra-arterial SBP was 24 ± 17mmHg (p < 0.01) and 20 ± 15 mmHg (p < 0.01) respectively. There was better correlation between intra-arterial diastolic blood pressure (DBP) and automated and manual DBP (r = 0.61, p < 0.01; r = 0.59, p < 0.01 respectively). The mean differences of the automated and manual DBP was not statistically significant when compared to the intra-arterial DBP. There was poor correlation between the intra-arterial MAP and the automated MAP (r = 0.44, p < 0.01) and good correlation with the manual MAP (r = 0.56, p < 0.01). The mean differences of the automated and manual MAP were statistically significant (5 ± 13mmHg, p < 0.01; 8 ± 11mmHg, p < 0.01 respectively). The sensitivity of automated and manual methods in detecting a SBP ≥ 160mmHg was 23.4% and 37.5% respectively. A MAP ≥ 125mmHg in detecting a SBP ≥ 160mmHg, when using intra-arterial, automated and manual methods of blood pressure measurements showed low sensitivity (35.9%, 21.9% and 17.2% respectively). CONCLUSION: This study demonstrated that both the automated and manual methods of blood pressure measurements were not an accurate measure of the true systolic intra-arterial blood pressure, when managing pre-eclamptic patients with acute severe hypertension. In such situations, intra-arterial blood pressure monitoring should be used when possible. When this is not possible, manual aneroid sphygmomanometry is recommended. Underestimating blood pressure, particularly SBP, may lead to severe maternal morbidity and mortality.
AFRIKAANSE OPSOMMING: DOELWIT: Die doel van hierdie studie is om die akuraatheid van nie invasiewe bloeddruk metings, wanneer geneem met outomatiese en manuele aparate, te vergelyk met intra-arteriele bloed druk metings in pasiente met pre-eklampsie, gedurende ‘n hipertensiewe bloeddruk piek. STUDIE ONTWERP: In hierdie prospektiewe beskrywende dwarssnit studie, was pasiente wat toegelaat was tot die Obstetriese Kritieke Sorg Eenheid met pre-eklampsie, akute erge hipertensie en ‘n intra-arteriele lyn in situ gevra om deel te neem. Gedurende ‘n intra-arteriele erge hipertensiewe piek is beide die outomatiese ossilometriese en die geblinde aneroide sfigmometer lesing neergeskryf. Hierdie twee metodes van non invasiewe bloed druk lesings is vergelyk met intra-arteriele bloed druk lesings. Die akuraatheid van ‘n gemiddelde arteriele bloeddruk ≥ 125mmHg om ‘n sistoliese bloeddruk ≥ 160mmHg op te tel met gebruik van al die drie metodes is ook uitgewerk. RESULTATE: Daar was swak korrelasie tussen intra-arteriele sistoliese bloed druk (SBD) metings en outomatiese en manuele SBD (r = 0.34, p < 0.01; r = 0.41, p < 0.01 onderskeidelik). Die gemiddelde verskille tussen outomatiese en manuele SBD wanneer vergelyk met intra-arteriele SBD was 24 ± 17mmHg (p < 0.01) en 20 ± 15 mmHg (p < 0.01) onderskeidelik. Beter korrelasie was gevind tussen intra-arteriele diastoliese bloed druk (DBD) en outomatiese en manuele DBD (r = 0.61, p < 0.01; r = 0.59, p < 0.01 onderskeidelik). Die gemiddelde verskille tussen outomatiese en manuele DBD wanneer dit vergelyk was met intra-arteriele DBD was nie statisties betekenisvol nie. Daar was swak korrelasie tussen intra arteriele gemiddelde arteriele bloeddruk en outomatiese gemiddelde arteriele bloeddruk (r = 0.44, p < 0.01) en beter korrelasie met manuele gemiddelde arteriele bloeddruk (r = 0.56, p < 0.01). Die gemiddelde verskille van outomatiese en manuele gemiddelde arteriele bloeddruk was betekenisvol (5 ± 13mmHg, p < 0.01; 8 ± 11mmHg, p < 0.01 onderskeidelik). Die sensitiwiteit van outomatiese en manuele metodes om ‘n intra-arteriele SBD ≥ 160mmHg op te tel was 23.4% en 37.5% onderskeidelik. Die vermoë van ‘n gemiddelde arteriele bloeddruk ≥ 125mmHg om ‘n SBD ≥ 160mmHg op te tel, gemeet deur intra-arterieel, outomatiese en manuele metodes het lae sensitiwiteit getoon (35.9%, 21.9% en 17.2% onderskeidelik). GEVOLGTREKKING: Hierdie studie het gedemonstreer dat outomatiese en manuele metodes van bloeddruk meting nie akurate metodes is om ware intra-arteriele sistoliese bloeddruk te meet in pasiente met erge pre-eklampsie tydens ‘n erge hipertensiewe episode nie. In hierdie omstandighede moet intra-arteriele bloeddruk gemeet word indien beskikbaar. Indien dit nie beskikbaar is nie moet die manuele aneroiede sfigmomanometer gebruik word. Onderskatting van bloeddruk, veral sistoliese bloeddruk, kan lei tot erge moederlike morbiditeit en mortaliteit.

L'utilité de toute technique de monitorage hémodynamique en réanimation est de procurer des informations fiables et reproductibles sur l'état cardio-circulatoire d'un patient présentant un état de choc. Les valeurs recueillies vont permettre au réanimateur de comprendre l'état dans lequel se trouve le patient et de prendre des décisions thérapeutiques plus éclairées dans le but d'optimiser l'état hémodynamique du patient et d'améliorer son pronostic. La surveillance hémodynamique est nécessaire pour évaluer la perfusion tissulaire globale et régionale. La correction de l'instabilité hémodynamique et de l'hypoperfusion tissulaire est essentielle pour prévenir la survenue d'une défaillance multiviscérale. La pratique de la réanimation est caractérisée par une relation temporelle très étroite entre la surveillance, la prise de décision et le traitement. Pour ce faire, le médecin réanimateur dispose d'un arsenal d'appareils de monitorage. Mais avant d'utiliser un dispositif, il est impératif que le clinicien ait de solides connaissances de la physiopathologie des états de choc afin de savoir quelles sont les paramètres qu'il souhaite monitorer. Dans la première partie de ce travail de thèse, nous nous sommes d'abord appliqués à rappeler quels sont les paramètres de monitorage hémodynamique disponibles pour le clinicien et le rationnel physiopathologique. Dans la deuxième partie de ce travail, nous avons présenté une revue des travaux originaux, les revues et les commentaires réalisés par l'auteur au cours de ces 4 dernières années sur plusieurs techniques de monitorage hémodynamique. Enfin, dans la troisième partie de ce travail, nous avons détaillé deux études expérimentales animales sur un modèle porcin en choc hémorragique : la première étudiant l'influence de l'hypovolémie sur le shunt intrapulmonaire d'animaux soumis à un syndrome de détresse respiratoire aigu par acide oléique et la seconde étude concernant l'impact des amines vasopressives sur les indices dynamiques de la réponse au remplissage vasculaire. Ces deux travaux expérimentaux mettent en évidence la complexité d'interprétation du monitorage hémodynamique dans des situations complexes comme le choc hémorragique
The usefulness of any technique hemodynamic monitoring in the ICU is to provide reliable and reproducible information on the cardio-circulatory status of a patient with shock. The collected values will allow the intensivist to understand the condition in which the patient is located and to take more informed treatment decisions in order to optimize the hemodynamic status and improve patient prognosis. Hemodynamic monitoring is needed to assess global and regional tissue perfusion. The correction of hemodynamic instability and tissue hypoperfusion is essential for prevent the occurrence of multiple organ failure. The practice of resuscitation is characterized by a very close temporal relationship between the monitoring, decision making and processing. To do this, numbers of monitoring devices are available. But before using a device, it is imperative for the clinician to have the knowledge of the pathophysiology of states shock to find out which parameters he wishes to monitor. In the first part of this thesis, we first recalled which hemodynamic monitoring parameters are available for the clinician and there pathophysiological rationals

Orientador: Gilberto de Nucci
Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Ciencias Medicas
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Resumo: Objetivo: Esta tese tem por objetivos: avaliar a agregação plaquetária e o comportamento da pressão arterial em três momentos (sem alho; alho dose única (3,5 g) e alho dose diária (3,5 g) duas vezes ao dia por 4 dias) em voluntários sadios; Analisar a resposta de agregação plaquetária in vitro adicionando extrato de alho diluído em PRP e por ultimo correlacionar os dados obtidos da analise da agregação com os parâmetros TxB2, GMPc entre in vivo e in vivo. Para Analise em in vivo foram selecionados dezoito (18) voluntários do sexo masculino, entre 18 a 45 anos, saudáveis, para estudo não randomizado, aberto e divididos em tres grupos (Grupo Sem alho; Grupo Com Alho Único e Grupo Alho Diário). Amostras de sangue dos voluntários foram coletadas de acordo com horários pré-estabelecidos. Após execução da agregação plaquetária, Pressão arterial através da MAPA e quantificação dos níveis de TXB2, foram realizadas análises estatisticas. Para analise in vitro foram selecionados 5 voluntários sadios, de ambos os sexos, isentos de qualquer medicação uma semana antes coleta. O sangue foi coletado e o PRP foi separado e adicionado extrato de alho em volume determinado. Após execução da agregação plaquetária e quantificação dos níveis de TXB2, foram tb realizadas análises estatisticas. Tendo estes dados tanto in vivo quanto in vivo procedeu-se a analise comparativa entre eles. Resultados : Na analise in vivo, tanto a agregação plaquetária quanto a inibição da formação de TxB2 não se observou diferença entre os outros grupos independente do agonista utilizado. Na analise in vitro, os resultados sugeriram que o extrato de alho, em quantidades pequenas, inibi a agregação plaquetária Os resultados se confirmaram com o TXB2, pois quantidades de extrato que foram capazes de inibir a agregação plaquetária induzida por todos agonistas, inclusive àquela induzida por AA, não causou diminuição significativa da síntese de TXA2 induzida por AA. Houve variação significativa da PA sistólica e FC com administração diária de alho fresco comparada ao sem alho e alho único. Conclusão: Concluímos que outros mecanismos podem estar envolvidos na inibição da agregação plaquetária que não da inibição da ciclooxigenase plaquetária quando utilizado o extrato de alho. Não há uma inibição da agregação plaquetária através da ação sobre a ciclooxigenase quando observado em voluntários que ingeriram alho fresco. A administração de alho in natura, pequenas quantidades (3,5g de dente de alho = 16 mg alicina/g de alho) pode contribuir para promover alterações no comportamento hemodinâmico como observado através da MAPA em voluntários sadios
Abstract: Objective: This thesis has as objectives: to evaluate the platelet aggregation and the behavior of blood pressure in three moments (control; garlic single dose (3,5 g) and garlic daily dose (3,5 g) twice a day for 4 days) in healthy volunteers; To analyze the in vitro platelet aggregation answer adding garlic extract diluted in PRP and the last to correlate the obtained data from the aggregation analysis with the TxB2, GMPc parameters between in vivo and in vivo. For the in vivo Analysis eighteen (18) healthy volunteers of the masculine gender between 18 and 45 years old were selected, for an open, non-randomized study and divided into three groups (Control; Group With Single Garlic and Group Daily Garlic). Samples of the volunteers' blood were collected according to the pre-established schedules. After execution of the platelet aggregation, blood Pressure through AMBP and quantification of TXB2 levels , statistical analyses were accomplished. For in vitro analysis 5 healthy volunteers of both genders were selected, free of any medication one week before collection. The blood was collected and the PRP was separated and added garlic extract in determined volume. After execution of the platelet aggregation and quantification of TXB2 levels, statistical analyses were also accomplished. Having these in vivo data as well in in vivo the comparative analysis between them was preceeded. Results: There was significant variation of the systolic BP and HR with daily administration of fresh garlic compared to control and single garlic. Regarding the platelet aggregation it was observed difference between the daily garlic group and the other two groups (P <0.005) when used agonist arachidonic acid. In the in vitro analysis, the results suggested that the garlic extract, in small amounts, can inhibit the platelet aggregation without affecting in a significant way the activity of ciclooxygenase. The results were confirmed with the TXB2, for amounts of extract that were capable to inhibit the platelet aggregation induced by all agonists, including that one induced by AA, didn't cause significant decrease of TXA2 synthesis induced by AA. Conclusion: We concluded that other mechanisms can be involved in the inhibition of the platelet aggregation other than the inhibition of the platelet ciclooxygenase when used the garlic extract. There is not an inhibition of the platelet aggregation through the action on the ciclooxygenase when observed in volunteers that ingested fresh garlic. The administration of garlic in natura, small quantities (3,5g garlic glove = 16 mg allicim/g garlic) can contribute to promote alterations in the hemodynamic behavior as observed through the AMBP in healthy volunteers
Doutorado
Clinica Medica
Doutor em Clínica Médica

Orientador: Newton Nunes
Banca: Valéria Nobre Leal de Souza Oliva
Banca: Roberta Carareto
Banca: Paulo Sérgio Patto dos Santos
Banca: José Antonio Marques
Resumo: Avaliaram-se os efeitos da infusão contínua de propofol ou tiopental sobre os parâmetros respiratórios, hemodinâmicos, hemogasométricos e do índice biespectral em cães portadores de hipertensão pulmonar (HP) induzida pela serotonina (5-HT). Utilizaram-se 20 cães adultos SRD, machos ou fêmeas, distribuídos em dois grupos de dez animais denominados grupo propofol (GP, n= 10) e grupo tiopental (GT, n = 10). O peso médio dos cães no GP foi 11,8 ± 1,8 kg e no GT 10,6 ± 2,7 kg. O propofol foi empregado na indução (8 ± 0,03 mg/kg) e manutenção da anestesia (0,8 mg/kg/min) no GP, e o tiopental foi utilizado para indução (22 ± 2,92 mg/kg) seguido por infusão contínua (0,5 mg/kg/min) no GT. Em seguida, a ventilação mecânica ciclada a tempo foi iniciada. A HP foi induzida pela administração de 5-HT em bolus (10 μg/kg) seguido por infusão contínua (1 mg/kg/h) na artéria pulmonar. As mensurações dos parâmetros tiveram início antes da aplicação (M0) e após 30 minutos da administração da 5-HT (M30), seguida de intervalos de 15 minutos (M45, M60, M75 e M90). As variáveis foram submetidas à Análise de Perfil (p<0,05). O coeficiente de Pearson foi calculado em ambos os grupos para determinar a correlação entre mistura arteriovenosa (Qs/Qt) e diferença de tensão entre o oxigênio alveolar e o arterial (AaDO2), entre Qs/Qt e o índice respiratório (IR), entre Qs/Qt e a relação artérioalveolar (a/A) e entre Qs/Qt e o índice de oxigenção (IO). Os resultados mostraram que a indução da HP alterou as variáveis hemogasométricas, respiratórias, a frequência cardíaca (FC), sendo registradas diferenças significativas entre os grupos ... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: The effects of continuous infusion of propofol or thiopental on respiratory, hemodynamic, blood-gas parameters and on bispectral index, in dogs induced to pulmonary hypertension (PH) by serononin (5-HT), were evaluated. Twenty adult mongrel dogs, male or female, were randomly assigned into two groups composed by ten animals: propofol group (PG, n = 10) and thiopental group (TG, n= 10). In PG, dogs weighing 11.8 ± 1.8 kg and in TG, 10.6 ± 2.7 kg. Propofol was used for induction (8 ± 0.03 mg/kg) and maintenance of anesthesia (0.8 mg/kg/minute) in PG. Thiopental was used for induction (22 ± 2.92 mg/kg) followed by continuous infusion (0.5 mg/kg/minute) in TG. Mechanical ventilation using time cycled was started. PH was induced by administration of a serotonin (5-HT) bolus (10 μg/kg) followed by continuous infusion (1 mg/kg/hour) in the pulmonary artery. The parameters were measured before administration of 5-HT (T0), after 30 minutes (T30) and, then, at 15-minute intervals (T45, T60, T75 and T90). Numeric data were submitted to Profile analysis (P<0.05). Pearson's coefficient was calculated in both groups to determine the correlation between venous admixture (Qs/Qt) and alveolar-arterial oxygen tension difference (AaDO2), between Qs/Qt and respiratory index (RI), between Qs/Qt and alveolo-arterial ratio (a/A) and between Qs/Qt and oxygenation index (IO) ... (Complete abstract click electronic access below)
Doutor

Laboratory tests are a primary resource for diagnosing patient diseases. However, physicians often make decisions based on a single laboratory result and have a limited perspective of the role of commonly-measured parameters in enhancing the diagnostic process. By providing a dynamic patient profile, the diagnosis could be more accurate and timely, allowing physicians to anticipate changes in the recovery trajectory and intervene more effectively. The assessment and monitoring of the circulatory system is essential for patients in intensive care units (ICU). One component of this system is the platelet count, which is used in assessing blood clotting. However, platelet counts represent a dynamic equilibrium of many simultaneous processes, including altered capillary permeability, inflammatory cascades (sepsis), and the coagulation process. To characterize the value of dynamic changes in platelet count, analytical methods are applied to datasets of critically-ill patients in (1) a homogeneous population of ICU cardiac surgery patients and (2) a heterogeneous group of ICU patients with different conditions and several hospital admissions. The objective of this study was to develop a methodology to anticipate adverse events using metrics that capture dynamic changes of platelet counts in a homogeneous population, then redefine the methodology for a more heterogeneous and complex dataset. The methodology was extended to analyze other important physiological parameters of the circulatory system (i.e., calcium, albumin, anion gap, and total carbon dioxide). Finally, the methodology was applied to simultaneously analyze some parameters enhancing the predictive power of various models. This methodology assesses dynamic changes of clinical parameters for a heterogeneous population of ICU patients, defining rates of change determined by multiple point regression and by the simpler fixed time parameter value ratios at specific time intervals. Both metrics provide prognostic information, differentiating survivors from non-survivors and have demonstrated being more predictive than complex metrics and risk assessment scores with greater dimensionality. The goal was to determine a minimal set of biomarkers that would better assist care providers in assessing the risk of complications, allowing them alterations in the management of patients. These metrics should be simple and their implementation would be feasible in any environment and under uncertain conditions of the specific diagnosis and the onset of an acute event that causes a patient's admission to the ICU. The results provide evidence of the different behaviors of physiologic parameters during the recovery processes for survivors and non-survivors. These differences were observed during the first 8 to 10 days after a patient's admission to the ICU. The application of the presented methodology could enhance physicians' ability to diagnose more accurately, anticipate changes in recovery trajectories, and prescribe effective treatment, leading to more personalized care and reduced mortality rates.

Minimally invasive hemodynamic monitoring in intensive care: methodological approach The aim of the study was to validate the reliability of some new systems of hemodynamic monitoring: the Nexfin system (BMEYE BV, Amsterdam, Netherlands ) totally non-invasive, and the Pressure-Recording Analytical Method (PRAM/MostCare, Vygon, Italy ), minimally invasive and without the need of calibration, either external or internal. MATERIALS AND METHODS NEXFIN. We enrolled 40 patients admitted to two intensive care units at Padua Hospital. For each patient we collected data about systolic blood pressure (SBP) and diastolic blood pressure (DBP) continuously for 30 minutes, both using standard intra-arterial method (IBP) and Nexfin system (“finger cuff” technology). We compared a total of 79263 pairs of blood pressure values. On 9 patients we compared the value of cardiac output (CO) with the value measured by trans-thoracic echocardiography Doppler (TTE ) . PRAM. We connected the PRAM system to a Siemens sc7000 monitor linked to a sophisticated simulator HPS/METI® HPS/METI® which can produce different CO values according to the clinical conditions set. We simulated 6 different clinical scenarios to obtain a total of 168 measurements of CO . In the second step, we tested the system on 38 hemodynamically stable patients by comparing the values of CO with those measured by TTE with Doppler technique. Finally, we compared the CO data on 21 hemodynamically unstable patients, supported by Norepinephrine in continuous infusion, by comparing the CO values with those measured by transpulmonary thermodilution system: PiCCO2 (Pulse Contour Cardiac Output, Pulsion Medical Systems, Munich, Germany ). We compared the data before (T1) and after (T2) the reduction of 0,05 mcg/kg/min of the drug. The results obtained were analyzed according to the Bland and Altman method. We calculated mean differences, limits of agreement and percentual errors. RESULTS NEXFIN. We collected 158525 pressure points, 79263 for each device: for SBP the mean a difference was -4,89 mmHg, limits of agreement were +18,11mmHg/-27,91 mmHg, %error 18%; for DBP the mean difference was +6.07 mmHg, limits of agreement +23,60/-11,45 mmHg, with %error of 26%. For values of CO we calculated a mean difference of -0,5 L/min, with limits of agreement +2.24/-3.38 L/min. PRAM/MostCare. The comparison of 168 values of CO with those set to HPS/METI® showed a mean difference of -0,32 L/min, limits of agreement respectively +0,88 and -1,53 L/min. The %error calculated was 23%; R2 = 78.1%. The comparison of the values of CO with those measured with TTE on 38 stable patients showed a mean difference of -0,03 L/min (SD 0,66) and the limits of agreement respectively between + 1,28 e -1,35 L/min. The comparison of the values of CO with those measured by transpulmonary thermodilution on 21 hemodynamically unstable patients showed a mean difference of 0,13 L/min at T1 and 0,1 L/min at T2, with limits of agreement = -1,41/1,69 L/min at T1 and -1,67/1,87 L/min at T2. The percentage error at T1 was 28,27%, at T2 was 32%. In the subgroup of patients with atrial fibrillation, the mean difference was 0,28 L/min at T1, with the limits of agreement of -0,79 and +1,37 L/min and with a %error of 22%; at T2 the mean difference was 0,55 L/min, the limits of agreement were between -1,82 and 2,93 L/min and the error rate was 49%. CONCLUSIONS About Nexfin we can conclude that the values of SBP, DBP and CO measured by this device can not be considered reliable in critically ill patients; there might be a more appropriate application in the operating room or in medical departiments. The method remains strongly linked to correctly reading the wave form, which appears to be strongly influenced by several pathophysiological and environmental variables . Regarding PRAM, in relation to the CO measurement compared with both the TTE and the method of the transpulmonary thermodilution, its application seems useful in the context of critically ill patients, providing fundamental information about hemodynamic setting to the intensivist without risk. To confirm our results the study needs to be expand to include more hemodynamically unstable patients as well as patients affected by atrial fibrillation. The PRAM system is operator-dependent: it needs to be used by experienced staff, who are able to asses the correct arterial wave form.
Monitoraggio emodinamico mini-invasivo in terapia intensiva: approccio metodologico Negli ultimi anni sono stati proposti diversi sistemi di monitoraggio emodinamico che promettono una buona affidabilità a fronte di una minima invasività. Scopo dello studio è stato quello di validarne alcuni, in particolare il sistema Nexfin (BMEYE BV, Amsterdam, Paesi Bassi) nuovo e totalmente non invasivo, e il Pressure-Recording Analytical Method (PRAM/Mostcare, Vygon, Italia), mini-invasivo e che non necessita di calibrazione né esterna, né interna. MATERIALI E METODI Abbiamo studiato i due sistemi testandoli su pazienti ricoverati in due terapie intensive polivalenti dell’Azienda Ospedaliera di Padova. Per il sistema Nexfin abbiamo arruolato 40 pazienti, per ognuno abbiamo rilevato per 30 minuti in continuo la pressione arteriosa sistolica (SBP) e diastolica (DBP), sia con il metodo standard della cannulazione intra-arteriosa (IBP) che con il sistema Nexfin (tecnologia finger cuff) e abbiamo confrontato un totale 79263 coppie di valori pressori. Su 9 pazienti abbiamo confrontato anche il valore di cardiac output (CO) con quello misurato mediante ecografia transtoracica con tecnica Doppler (TTE). Per quanto riguarda il sistema PRAM lo abbiamo collegato mediante cavo ad un monitor Siemens sc7000 connesso ad un sofisticatissimo simulatore HPS/METI®, in grado di riprodurre valori di CO diversi in base alle condizioni cliniche impostate. Abbiamo simulato 6 scenari clinici differenti per ottenere un totale di 168 misurazioni di CO che abbiamo confrontato con quelli noti risultanti dalle impostazioni del simulatore. Successivamente abbiamo testato il sistema su 38 pazienti emodinamicamente stabili confrontando i valori di CO con quelli misurati mediante TTE con tecnica Doppler. Infine abbiamo confrontato i dati di CO su 21 pazienti emodinamicamente instabili e sostenuti da Noradrenalina in infusione continua, confrontando i valori di CO con quelli misurati tramite termodiluizione transpolmonare con sistema PiCCO2 (Pulse Contour Cardiac Output, Pulsion Medical System, Munich, Germany). Abbiamo confrontato i dati prima (T1) e dopo (T2) la riduzione di 0,05 mcg/Kg/min del farmaco. I risultati ottenuti sono stati analizzati statisticamente secondo il metodo di Bland e Altman; sono state calcolate le differenze medie, i livelli di concordanza e le percentuali d’errore. RISULTATI NEXFIN. Su un totale 158525 punti pressione, 79263 per dispositivo, abbiamo ottenuto per la SBP una mean difference di -4,89 mmHg, dei limits of agreement di +18,11mmHg e -27,91 mmHg ed un errore percentuale del 18% e per la DBP una mean difference di +6,07 mmHg, dei limits of agreement di +23,60 mmHg e -11,45 mmHg, con una percentuale d’errore del 26%. Per i valori di CO abbiamo calcolato una mean difference -0,5 L/min, con dei limits of agreement rispettivamente di +2,24 e -3,38 L/min. PRAM/Mostcare. Il confronto di 168 valori di CO con quelli impostati su HPS/METI® ha mostrato una mean difference di -0,32 L/min e dei limits of agreement rispettivamente di +0,88 e -1,53 L/min. L’errore percentuale calcolato era del 23%. con un R2 = 78,1%. Il confronto dei valori di CO con quelli misurati con TTE su 38 pazienti stabili ha mostrato una mean difference di -0,03 L/min (SD 0,66) e dei limits of agreement rispettivamente compresi tra + 1,28 e -1,35 L/min. Il confronto dei valori di CO con quelli misurati con termodiluizione transpolmonare su 21 pazienti emodinamicamente instabili ha evidenziato una mean diffenrence di 0,13 L/min al T1 e di 0,1 L/min al T2, con dei limits of agreement rispettivamente compresi tra -1,41 e 1,69 L/min e tra -1,67 e 1,87 L/min. L’errore percentuale al T1 è risultato essere pari al 28,27%, al T2 era pari al 32%. Nel sottogruppo di pazienti affetti da fibrillazione atriale la mean difference era di 0,28 L/min a T1, con dei limits of agreement di -0,79 e +1,37 L/min e con un errore percentuale del 22%; al T2 la mean difference era di 0,55 L/min, i limits of agreement erano compresi tra -1.82 e 2,93 L/min e la percentuale d’errore era del 49%. CONCLUSIONI Per quanto riguarda il sistema Nexfin possiamo concludere che i valori di SBP, DBP e CO misurati da questo device completamente non invasivo non possono essere considerati affidabili nei pazienti critici; la tecnologia finger-cuff può trovare probabilmente una più appropriata applicazione in sala operatoria o in ambito più prettamente medico. La metodica rimane fortemente vincolata da una corretta lettura del dato pressorio che ci è parso fortemente suscettibile a una serie di variabili fisiopatologiche e ambientali. Per quanto riguarda il sistema PRAM, in relazione alla misura del CO confrontata sia con la TTE che con il metodo della termodiluizione transpolmonare, la sua applicazione ci sembra possa trovare spazio nel paziente critico, fornendo all’intensivista informazioni fondamentali sull’assetto emodinamico senza rischi aggiunti. Resta la necessità di ampliare le popolazioni di studio relative ai pazienti emodinamicamente più instabili e a quelli affetti da fibrillazione atriale per poter confermare i nostri risultati. Il sistema PRAM è operatore-dipendente: richiede di essere utilizzato da personale esperto, in grado di valutare la corretta lettura dell’onda di pressione.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
Avaliaram-se os efeitos da infusão contínua de propofol ou tiopental sobre os parâmetros respiratórios, hemodinâmicos, hemogasométricos e do índice biespectral em cães portadores de hipertensão pulmonar (HP) induzida pela serotonina (5-HT). Utilizaram-se 20 cães adultos SRD, machos ou fêmeas, distribuídos em dois grupos de dez animais denominados grupo propofol (GP, n= 10) e grupo tiopental (GT, n = 10). O peso médio dos cães no GP foi 11,8 ± 1,8 kg e no GT 10,6 ± 2,7 kg. O propofol foi empregado na indução (8 ± 0,03 mg/kg) e manutenção da anestesia (0,8 mg/kg/min) no GP, e o tiopental foi utilizado para indução (22 ± 2,92 mg/kg) seguido por infusão contínua (0,5 mg/kg/min) no GT. Em seguida, a ventilação mecânica ciclada a tempo foi iniciada. A HP foi induzida pela administração de 5-HT em bolus (10 μg/kg) seguido por infusão contínua (1 mg/kg/h) na artéria pulmonar. As mensurações dos parâmetros tiveram início antes da aplicação (M0) e após 30 minutos da administração da 5-HT (M30), seguida de intervalos de 15 minutos (M45, M60, M75 e M90). As variáveis foram submetidas à Análise de Perfil (p<0,05). O coeficiente de Pearson foi calculado em ambos os grupos para determinar a correlação entre mistura arteriovenosa (Qs/Qt) e diferença de tensão entre o oxigênio alveolar e o arterial (AaDO2), entre Qs/Qt e o índice respiratório (IR), entre Qs/Qt e a relação artérioalveolar (a/A) e entre Qs/Qt e o índice de oxigenção (IO). Os resultados mostraram que a indução da HP alterou as variáveis hemogasométricas, respiratórias, a frequência cardíaca (FC), sendo registradas diferenças significativas entre os grupos...
The effects of continuous infusion of propofol or thiopental on respiratory, hemodynamic, blood-gas parameters and on bispectral index, in dogs induced to pulmonary hypertension (PH) by serononin (5-HT), were evaluated. Twenty adult mongrel dogs, male or female, were randomly assigned into two groups composed by ten animals: propofol group (PG, n = 10) and thiopental group (TG, n= 10). In PG, dogs weighing 11.8 ± 1.8 kg and in TG, 10.6 ± 2.7 kg. Propofol was used for induction (8 ± 0.03 mg/kg) and maintenance of anesthesia (0.8 mg/kg/minute) in PG. Thiopental was used for induction (22 ± 2.92 mg/kg) followed by continuous infusion (0.5 mg/kg/minute) in TG. Mechanical ventilation using time cycled was started. PH was induced by administration of a serotonin (5-HT) bolus (10 μg/kg) followed by continuous infusion (1 mg/kg/hour) in the pulmonary artery. The parameters were measured before administration of 5-HT (T0), after 30 minutes (T30) and, then, at 15-minute intervals (T45, T60, T75 and T90). Numeric data were submitted to Profile analysis (P<0.05). Pearson’s coefficient was calculated in both groups to determine the correlation between venous admixture (Qs/Qt) and alveolar-arterial oxygen tension difference (AaDO2), between Qs/Qt and respiratory index (RI), between Qs/Qt and alveolo-arterial ratio (a/A) and between Qs/Qt and oxygenation index (IO) ... (Complete abstract click electronic access below)

Introdução: Os anestésicos inalatórios empregados atualmente na prática clinica (isoflurano, sevoflurano e desflurano) possuem propriedades farmacocinéticas que favorecem rápida recuperação da anestesia, porém seu uso pode causar instabilidade hemodinâmica dose-dependente, relacionado à depressão direta da contratilidade miocárdica ou à hipovolemia relativa, derivado de um sequestro de sangue devido à vasodilatação do leito vascular periférico. Este estudo visa avaliar o comportamento da VPP durante a anestesia inalatória. Para tanto se utilizou três diferentes agentes inalatórios (isoflurano, sevoflurano e desflurano) em diferentes concentrações inaladas. Métodos: Foram utilizados 25 suínos divididos aleatoriamente em três grupos. Os animais foram submetidos à anestesia com o anestésico do respectivo grupo. Imediatamente após a determinação da CAM individual do agente inalatório em cada animal, ocorreu a primeira coleta de dados. O animal foi, então, exposto a diferentes níveis de CAM (1,0 CAM; 1,25 CAM) seguido por uma exposição decrescente de CAM (1,0 CAM); provocou-se então uma hemorragia correspondente a 30% da volemia e exposição a dois níveis de CAM (1,0 e 1,25), com 20 minutos em cada exposição. Ao final de cada período os valores ecocardiográficos e do VPP foram mensurados. A análise estatística foi realizada através de provas paramétricas empregando-se o método de comparações múltiplas para análise de variância com medidas repetidas (ANOVA). O grau de significância foi de 5% (p < 0,05). Resultados: Há aumento na variação de pressão de pulso com incremento de 25% na CAM dos anestésicos inalatórios (de 8±1 para 11±3% no grupo DESF, de 7±2 para 9±2 no grupo SEVO e de 9±4 para 10±3% no grupo ISO) sem diferença estatística entre os anestésicos. Apesar deste aumento na CAM e significativa hipotensão e queda no débito cardíaco, o aumento na VPP não torna o paciente responsivo a infusão de fluidos (o VPP permaneceu abaixo de 13%). Há pequena queda na PAM quando se eleva a CAM dos anestésicos em 25%, porém só há queda estatisticamente significativa no grupo DESF (de 84±7 para 68±12 mmHg). Não foram observadas alterações importantes em relação à contratilidade miocárdica. Conclusão: Observou-se que a VPP não é influenciada como o uso dos diferentes anestésicos inalatórios e apesar dos efeitos cardiovasculares esperados destes agentes, mantem-se a capacidade de demonstrar alterações de pré-carga mesmo em concentrações correspondentes a 1,25 CAM
Background: Inhalant anesthetics, such as isoflurane, sevoflurane and desflurane are widely used in daily clinical practice due to its pharmacological properties allowing a rapid recovery from anesthesia. Nevertheless, its use can lead to dose-dependent hemodynamic instability related to direct depression in myocardial contractility or to a relative hypovolemia caused by vasodilation of peripheral capillary bed. This study aims to evaluate the behavior of PPV during inhalant anesthesia. For this, three different anesthetics were used (isoflurane, sevoflurane and desflurane) with different inhaled concentrations. Methods: 25 young pigs were randomly assigned into three groups. Animals were anesthetized with its correspondent agent according to its group. After individual determination of minimal alveolar concentration (MAC), first data collection occurred. Pigs were then exposed to different MAC (1MAC and 1,25 MAC) followed by a decrease in MAC (1 MAC). At this point a 30% of estimated volemia hemorrhage was caused and pigs were exposed to a period of 1 MAC and after that 1,25 MAC. Each period lasted 20 minutes. At the end of each period, hemodynamic parameters and echocardiography were collected. Data were submitted to analysis of variance for repeated measures (ANOVA). P<0,05 was considered statistically significant. Results: There was an increase in PPV when with 1,25 MAC of all anesthetics. (from 8±1 to 11±3% in group DESF, from 7±2 to 9±2 in group SEVO and from 9±4 to 10±3% in group ISO), but without statistical difference among groups. Although there was an increase in PPV, followed by hypotension and drop in cardiac index, patients werent fluid responsive with a 25% increase in MAC, since PPV was lower than 13%. The decrease in blood pressure followed by 1,25MAC was only significant in DESF group (from 84±7 to 68±12 mmHg). No important alterations related to myocardial contractility were observed. Conclusion: PPV is not influenced by the use of different inhalant anesthetics and although there are cardiovascular effects of these agents which are expected, and were able to demonstrate alterations in preload even in concentration of 1,25 MAC

Es sollte untersucht werden, ob Ganzkörper-Hyperthermie (GKH) plus Chemotherapie im Rahmen systemischer Krebs-Mehrschritt-Therapie (sKMT) eine wiederholt anwendbare und verträgliche Therapieoption für Patienten mit fortgeschrittenen, metastasierten Tumorerkrankungen darstellt. Im klinischen Zusammenhang sollten funktionelle Veränderungen verschiedener Organsysteme und toxische Reaktionen unter GKH/sKMT aufgezeigt werden sowie das anästhesiologische Management hinsichtlich der Anwendung verschiedener Monitoringverfahren beurteilt werden. Bei 26 Patienten erfolgten in Allgemeinanästhesie Messungen von Hämodynamik, Gasaustausch, O2-Transport und Metabolismus sowie klinische, laborchemische und immunologische Analysen während und nach 63 GKH/sKMT-Behandlungen. Die GKH mit einer Plateauphase von einer Stunde bei 41,8°C wurde durch Infrarotstrahlung induziert. Das anästhesiologische Monitoring der Patienten beinhaltete Pulmonalarterienkatheter, Doppelindikator-Dilutionsverfahren, invasive und nicht-invasive Blutdruckmessung sowie Dopplersonografie. Es konnte gezeigt werden, dass heute eine GKH/sKMT in Allgemeinanästhesie und mit sorgfältiger Auswahl der Patienten ein verträgliches und sicheres Verfahren darstellt. Alterationen der gemessenen Parameter zeigten am Ende der Behandlung meistens eine deutliche Tendenz in Richtung der Initialwerte. Toxische Reaktionen konnten in einem akzeptablen Ausmaß gehalten und lang anhaltende Organschäden vermieden werden. Ein adäquates Monitoring beinhaltet eine invasive arterielle und zentralvenöse Druckmessung. Das hämodynamische Management sollte sich am mittleren arteriellen Blutdruck orientieren. Somit erscheint derzeit eine weitere Evaluierung dieser Therapie im Rahmen von multimodalen onkologischen Behandlungskonzepten sinnvoll.
This investigation was performed to investigate the safety of whole body hyperthermia (WBH) within the context of systemic Cancer Multistep Therapy (sCMT) in patients with disseminated malignancies. Furthermore, alterations in various organ functions and toxicities during WBH/sCMT as well as an appropriate anesthesiological management should be evaluated. 63 WBH/sCMT treatments in 26 patients were carried out under general anesthesia and measurements of hemodynamics, pulmonary gas exchange and metabolism as well as clinical, laboratory and immunological investigations were performed. WBH with a plateau phase of one hour at 41.8°C was induced by infrared radiation. Anesthesiological monitoring included pulmonary artery catheter, transpulmonary double indicator dilution technique, invasive and non-invasive blood pressure measurement and Doppler ultrasonography. By careful selection of patients WBH/sCMT can be performed safely using general anesthesia. Most parameters showed a clear tendency towards the pretreatment levels at the end of therapy. Toxicities stayed in an acceptable range and persistent organ dysfunctions could be avoided. An appropriate anesthesiological monitoring includes invasive arterial and central venous pressure measurements. Hemodynamic management during WBH should be guided by the mean arterial pressure. This enables further evaluation of WBH in multimodal treatment concepts.

The study of the brain using diffuse optical methods has progressed rapidly in the recent years. The possibility of studying the cerebral microvasculature in addition to the portability and low cost of these devices, opens a new door in the study of the cerebral pathophysiologies. In this scenario, the study of the cerebral hemodynamics of ischemic patients might allow neurologists to improve the performance of the early medical treatments and therapies used up to date. In this thesis, I have conducted a pioneering study where cerebral autoregulation was studied in ischemic stroke patients during the early hours after the stroke. Similarly, some other diseases can provoke impaired cerebral autoregulation in the long term. One of them is the obstructive sleep apnoea (OSA) syndrome which can provoke a risk increase of developing cardiovascular diseases and ischemic stroke. In this regards, I have carried out the largest to date study conducted with Diffuse Correlation Spectroscopy in patients with OSA and I have compared their hemodynamical response to an orthostatic challenge test with a control group of healthy subjects. Finally, primary animal research is of great importance in the development of new therapies, medical strategies and in the validation of new drugs with the aim of reducing the high mortality and slow and costly recovery of ischemic patients. In consequence, many models of ischemia are reproduced in rodents where the cerebral hemodynamics are studied using expensive equipments such as MRI scanners or by techniques that involve invasive approaches like for instance removing the scalp or thinning the skull which in turn cause a worsening in the living conditions of the animal. In relation to this point, I have developed a fully non-invasive method to study the cerebral hemodynamics in rats that allows to proceed with longitudinal studies and which I hope will be useful in future biomedical research.
El estudio del cerebro mediante métodos de óptica difusa ha progresado rápidamente en los últimos años. La posibilidad de estudiar la microvasculatura cerebral junto con la portabilidad y bajo coste de estos equipos abre una ventana de posibilidades para el estudio de fisiopatologías cerebrales. En este escenario, el estudio de la hemodinámica cerebral en pacientes isquémicos podría permitir a los neurólogos mejorar el rendimiento de los tratamientos médicos tempranos y de las terapias utilizadas hasta la fecha. En esta tesis he realizado un estudio pionero al respecto, estudiando por primera vez la hemodinámica cerebral de pacientes isquémicos durante las primeras horas después del infarto cerebral. De igual manera, existen otro tipo de enfermedades que pueden desarrollar un empeoramiento a largo plazo de la autorregulación cerebral. Entre ellas destaca el síndrome de apnea obstructivo (SAO), debido al cual el empeoramiento de la hemodinámica cerebral provoca un aumento del riesgo directo de sufrir enfermedades cardiovasculares y un aumento del riesgo de infarto cerebral. Al respecto, he llevado a cabo el mayor estudio hasta la fecha con pacientes con SAO donde he estudiado su respuesta hemodinámica a un test ortostático comparado estos resultados con los obtenidos en grupo de control de pacientes sanos. Finalmente, la investigación primaria en animales es de vital importancia en el desarrollo de nuevas terapias y estrategias médicas así como en la validación de nuevos fármacos que reduzcan la alta mortalidad y la lenta y costosa recuperación de los pacientes isquémicos. En consecuencia, numerosos modelos de isquemia son reproducidos en roedores donde se estudia la hemodinámica cerebral mediante caros equipos como los resonadores magnéticos o mediante técnicas que implican someter al animal a cierta cirugía en la que se le sustrae el cuero cabelludo o se le lima el cráneo. En relación con esto último, he desarrollado un método completamente no invasivo para estudiar la hemodinámica cerebral en ratas y que permite llevar a cabo estudios longitudinales, el cual espero sea utilidad en futuras investigaciones biomédicas.

Many cerebral diseases are associated with abnormal cerebral hemodynamics and impaired cerebral autoregulation (CA). CA is a mechanism to maintain cerebral blood flow (CBF) stable when mean arterial pressure (MAP) fluctuates. Evaluating these abnormalities requires direct measurements of cerebral hemodynamics and MAP. Several near-infrared diffuse optical instruments have been developed in our laboratory for hemodynamic measurements including near-infrared spectroscopy (NIRS), diffuse correlation spectroscopy (DCS), hybrid NIRS/DCS, and dual-wavelength DCS flow-oximeter. We utilized these noninvasive technologies to quantify CBF and cerebral oxygenation in different populations under different physiological conditions/manipulations. A commercial finger plethysmograph was used to continuously monitor MAP. For investigating the impact of obstructive sleep apnea (OSA) on cerebral hemodynamics and CA, a portable DCS device was used to monitor relative changes of CBF (rCBF) during bilateral thigh cuff occlusion. Compared to healthy controls, smaller reductions in rCBF and MAP following cuff deflation were observed in patients with OSA, which might result from the impaired vasodilation. However, dynamic CAs quantified in time-domain (defined by rCBF drop/MAP drop) were not significantly different between the two groups. We also evaluated dynamic CA in frequency-domain, i.e., to quantify the phase shifts of low frequency oscillations (LFOs) at 0.1 Hz between cerebral hemodynamics and MAP under 3 different physiological conditions (i.e., supine resting, head-up tilt (HUT), paced breathing). To capture dynamic LFOs, a hybrid NIRS/DCS device was upgraded to achieve faster sampling rate and better signal-to-noise. We determined the best hemodynamic parameters (i.e., CBF, oxygenated and total hemoglobin concentrations) among the measured variables and optimal physiological condition (HUT) for detecting LFOs in healthy subjects. Finally, a novel dual-wavelength DCS flow-oximeter was developed to monitor cerebral hemodynamics during HUT-induced vasovagal presyncope (VVS) in healthy subjects. rCBF was found to have the best sensitivity for the assessment of VVS among the measured variables and was likely the final trigger of VVS. A threshold of ~50% rCBF decline was observed which can completely separate subjects with or without presyncope, suggesting its potential role for predicting VVS. With further development and applications, NIRS/DCS techniques are expected to have significant impacts on the evaluation of cerebral hemodynamics and autoregulation.

Orientador: Ana Terezinha Guillaumon
Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Ciências Médicas
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Resumo: Introdução: A espectroscopia próxima ao infra-vermelho (NIRS) é uma técnica não invasiva e de baixo custo que detecta as alterações hemodinâmicas teciduais. O NIRS pode monitorar de forma contínua as informações fisiológicas vasculares intracranianas. Por ser portátil, ele pode ser utilizado a beira do leito e no centro cirúrgico. Objetivo: Avaliar o comportamento das possíveis alterações hemodinâmicas cerebrais, durante a endarterectomia, em pacientes com estenoses maiores que 70%, utilizando NIRS. Casuística e métodos: Foram avaliados 10 voluntários portadores de doença carotídea aterosclerótica com indicação de endarterectomia. Após a seleção dos pacientes que responderam um questionário com dados epidemiológicos e informações referentes a presença de comorbidades, a doença foi confirmada por métodos diagnósticos. No procedimento cirúrgico utilizou-se o NIRS para monitorização. Foram avaliadas as variáveis saturação de oxigênio (Sat O2) hemoglobina total (HbT), hemoglobina reduzida (HbR) e hemoglobina oxigenada (HbO) nos três tempos cirúrgicos pré, trans e pós-clampeamento carotídeo. Resultados: Utilizou-se p<0,05 como nivel de significância. A avaliação dos resultados obtidos através das medidas registradas pelo NIRS permite afirmar que as etapas da cirurgia diferem quanto ás variável HbR e SatO2. Durante a etapa do clampeamento, a variável HbR mostra valores mais elevados que nas outras duas etapas da cirurgia. De outra parte, a variável SatO2 mostra redução durante o clampeamento. Conclusão: O NIRS é um método viável e aplicável de monitorização intracerebral, não-invasivo e em tempo real, durante a endarterectomia carotídea, capaz de medir de forma precisa as mudanças das condições hemodinâmicas capilares intra-cerebrais
Abstract: Introduction: Near-infrared spectroscopy (NIRS) is a low-cost, non-invasive technique that detects tissue hemodynamic alterations. It enables continuous monitoring of the intracerebral vascular physiologic information. Due to its portable nature, NIRS may be used beside a bed or in the operating room. Objective: To evaluate the use of NIRS for intra-surgical monitoring of the brain hemodynamic response, during an endarterectomy procedure of the atherosclerotic carotid artery. Casuistry and Methods: 10 patients with atherosclerotic carotid disease and recommended endarterectomy were evaluated. They were identified in a survey which provided epidemiologic data and the presence of comorbidities. Disease was confirmed by diagnostic methods. NRIS monitoring was used during the surgical procedure. Oxygen saturation (O2 Sat), total hemoglobin (THb), reduced hemoglobin (RHb), and oxyhemoglobin (OHb) were the variables analyzed at the three carotid clamp stages: pre-, trans- and post-. Results: A p<0.05 value was considered statistically significant. The results obtained from the NIRS data reveal that the surgical stages differ in relation to the RHb and O2Sat variables. RHb presents higher levels during clamping when compared with the other two surgical stages. On the other hand, O2Sat is decreased during clamping. Conclusion: NIRS is a feasible, realtime and non-invasive intracranial monitoring method, during carotid endarterectomy, which measures accurately and reliably the changes of the intracerebral capillary hemodynamic conditions
Mestrado
Cirurgia
Mestra em Ciências

Noninvasive measurement of hemodynamics at the microvascular level may have a great impact on oncology in clinics for diagnosis, therapy planning and monitoring, and, in preclinical studies. To this end, diffuse optics is a strong candidate for noninvasive, repeated, deep tissue monitoring. In this multi-disciplinary, translational work, I have constructed and deployed hybrid devices which are the combination of two qualitatively different methods, near infrared diffuse optical spectroscopy (NIRS) and diffuse correlation spectroscopy (DCS), for simultaneous measurement of microvascular total hemoglobin concentration, blood oxygen saturation and blood flow. In a preclinical study, I applied the hybrid device to monitor the response of renal cell carcinoma in mice to antiangiogenic therapy. The results suggest that we can predict the output of therapy from early hemodynamic changes, which provide us with valuable information for better understanding of the tumor resistance mechanism to antiangiogenic therapies. In two in vivo studies in human volunteers, I have developed protocols and probes to demonstrate the feasibility of noninvasive diffuse optical spectroscopy to investigate the pathophysiology of bone. First study was study on the physiology of the patella microvasculature, the other introduced the manubrium as a site that is rich in red bone mar- row and accessible to diffuse optics as a potential window to monitor the progression of hematological malignancies. Overall, during my Ph.D., I have developed instrumentation, algorithms and protocols and, then, applied this technique for preclinical and clinical investigations. My research is a link between preclinical and clinical studies and it opens new areas of applications in oncology.
La medición no invasiva de la hemodinámica a nivel microvascular puede alcanzar un gran impacto en oncología: en las clínicas para el diagnóstico, la planeación y monitorización de las terapias, y en estudios preclínicos. La óptica difusa es una fuerte candidata para la monitorización no invasiva y repetida del tejido profundo. En este trabajo multidisciplinario y traslacional, construí e implementé dispositivos híbridos que son la combinación de dos métodos cualitativamente diferentes: espectroscopía infrarroja de óptica difusa -near infrared diffuse optical spectroscopy (NIRS)- y espectroscopía de correlación de luz difusa -diffuse correlation spectroscopy (DCS)-. Estos híbridos permiten la medición simultánea de la concentración de hemoglobina total en sangre, la saturación de oxígeno y el flujo sanguíneo. En un estudio preclínico, apliqué el dispositivo híbrido para monitorizar la respuesta de carcinomas de células renales, implantados en ratones, a terapias antiangiogénicas. Los resultados sugieren que podemos predecir la evolución de la terapia con base en cambios hemodinámicos tempranos, lo cual proporciona información valiosa para un mejor entendimiento del mecanismo de resistencia de los tumores a las terapias antiangiogénicas. En dos estudios in vivo realizados en pacientes voluntarios, desarrollé protocolos y sondas para demostrar la viabilidad de la espectroscopía de óptica difusa no invasiva en el estudio de la patofisiología ósea. El primer estudio se concentró en la fisiología microvascular de la rótula y en el otro se muestra que el manubrio, hueso rico en médula ósea roja, es un sitio accesible para la óptica difusa, y se presenta como una ventana para monitorizar la progresión de enfermedades hematológicas malignas. En resumen, durante mi trabajo doctoral, desarrollé instrumentación, algoritmos y protocolos que posteriormente apliqué en estudios preclínicos y clínicos. Mi trabajo de investigación constituye así un enlace entre estos estudios y abre nuevas áreas de aplicación en oncología.

El shock es un estado de disoxia tisular, donde el desequilibrio entre el aporte y el consumo de oxígeno genera disfunción tisular, fracaso multiorgánico y finalmente la muerte. Por todo ello supone una urgencia médica. Actualmente las recomendaciones a la hora de resucitar a un paciente en shock abogan por la optimización de la presión arterial media (PAM) y la búsqueda de la normalización de los valores de la saturación venosa central de oxígenos (SvcO2) y lactato. No obstante, estos parámetros macrohemodinámicos, parecen ser insuficientes. En los últimos años, se ha demostrado el valor pronóstico de la presión venosa central a arterial de dióxido de carbono (PcvaCO2) en distintas condiciones, lo que ha generado que sea propuesto como marcador adicional de la adecuación en la perfusión tisular. Existen numerosos trabajos que muestran la asociación entre PcvaCO2 y gasto cardíaco, y su capacidad discriminativa a pesar de niveles normales de SvcO2, por lo que desde hace años ha sido introducido como un objetivo más en el proceso de la resucitación hemodinámica. No obstante, el PcvaCO2 no se ha explorado de forma prospectiva, y podría ser una variable más compleja de lo pensado inicialmente. Además, el PcvaCO2, no parece ser tan bueno a la hora de detectar estados de anaerobiosis, y algunos autores han propuesto la utilización del PcvaCO2 corregido por el contenido arterio-venoso de O2 (CavO2), cálculo aproximativo del coeficiente respiratorio. Este supone la corrección de la producción global de CO2 (VCO2) por el consumo global de oxígeno (VO2). De acuerdo con la ecuación de Fick, el coeficiente respiratorio es equivalente al contenido venoso central a arterial de dióxido de carbono (CcvaCO2) dividido por el CavO2. Atendiendo que el valor fisiológico del contenido de dióxido de carbono incluye la presión parcial, se atribuye una relación lineal de ambas variables, siendo aceptada la utilizando el PcvaCO2 como un subrogado del CcvaCO2. No obstante la intercambiabilidad de dichas variables es un tema de debate. En el presente trabajo de tesis doctoral se ha pretendido dar respuesta a diferentes aspectos clínicos en relación a las variables derivadas del dióxido de carbono (CO2) como son el PcvaCO2 y el PcvaCO2/CavO2. Fundamentalmente, se ha analizado su asociación con la presencia de metabolismo anaerobio, la interacción de diversos parámetros en la relación entre contenido y presión de CO2, así como su valor pronostico en las fases precoces del paciente en shock séptico.
Shock is a state of tissue disoxia, where the imbalance between transport and oxygen consumption generates tissue dysfunction, multiorgan failure and finally death. This is why it implies a medical emergency. Currently the recommendations when resuscitating a patient in shock, advocate to the optimization of mean arterial pressure (PAM) and the search for the normalization of the values ​​of central venous oxygen saturation (SvcO2) and lactate. However, those macrohemodynamic parameters seem to be insufficient. In recent years, the prognostic value of the central venous-to-arterial carbon dioxide difference (PcvaCO2) gap has been demonstrated in different conditions, which has led to its being proposed as an additional marker of adequacy in tissue perfusion. There are numerous studies that show the association between PcvaCO2 and cardiac output and its discriminative capacity despite normal levels of SvcO2, thus, few years ago it has been introduced as another objective in the process of hemodynamic resuscitation. However, PcvaCO2 has not been explored prospectively, and could be a more complex variable than originally thought. In addition, PcvaCO2 does not seem to be as good at detecting anaerobic states, and some authors have proposed the use of PcvaCO2 corrected for the arterial-venous O2 content (CavO2). This parameter supposes an approximate calculation of the respiratory coefficient. This supposes the correction of the global production of CO2 (VCO2) by the global consumption of oxygen (VO2). According to the Fick equation, the respiratory coefficient equivalent to central venous-to-arterial carbon dioxide content (CcvaCO2) corrected by CavO2. Considering that the physiological value of the carbon dioxide content (CCO2) includes partial pressure (PCO2), a linear relationship of both variables is attributed, being accepted using PcvaCO2 as a surrogate of CcvaCO2. However, the equivalence of these variables is a matter of debate. In the present work of doctoral thesis has sought to respond to different clinical aspects in relation to the variables derived from carbon dioxide (CO2) such as PcvaCO2 and PcvaCO2/CavO2. Basically, its association with the presence of anaerobic metabolism, the interaction of various parameters in the relationship between content and CO2 pressure, as well as its prognostic value in the early phases of the patient in septic shock has been analyzed.

According to the World Health Organization (WHO), cardiovascular (CV) diseases are the number one cause of death globally, and are projected to remain the single leading cause of death by 2030. Central pulse pressure and several arterial stiffness indices, especially aortic pulse wave velocity (PWV), are among the strongest predictors of CV events, including stroke, myocardial infarction (heart attack) and angina (chest pain). Therefore, non-invasive methods for the assessment of the central pressure and central arterial stiffness are very important for the diagnosis of CV diseases at their early stage of development. In this thesis, non-invasive methods are developed to (i) measure the aortic PWV, and (ii) measure the aortic pressure waveform (APW). In the intensive care unit, cardiac output (CO) is an important measure of the adequacy of circulation among post-operative patients of cardiovascular diseases. Current methods of monitoring use the heart rate, peripheral blood pressure, and urine output as surrogates of CO, but these indices are inadequate. CO can be monitored directly using thermodilution but the procedure is highly invasive. In this thesis, a minimally-invasive method is developed to monitor the CO using the radial artery pressure waveform. The underlying algorithms of the methods developed in this thesis are interrelated. In this thesis, the arterial system is modeled as a single uniform lossless transmission line terminated by a complex load. Each measuring and monitoring task is a problem of identification, simulation or data acquisition. The measurement of the aortic PWV is formulated as an identification problem. The method developed in this thesis was shown to be able to differentiate a group of children with Marfan syndrome from the healthy children. The monitoring of CO is formulated as a problem of identification and simulation. The method developed in this thesis was applied to five post-surgical infants. It showed clinically acceptable agreement with the more established echocardiographic technique. The measurement of APW is a problem of data acquisition. A method was developed to estimate APW from the aortic distension waveform obtained using B-mode ultrasound. This method showed good agreement with carotid artery applanation tonometry when applied to nine healthy children.

Introdução: Prever a capacidade de resposta a fluidos continua sendo um desafio para os médicos que lidam com pacientes instáveis hemodinamicamente. A utilização de parâmetros estáticos, como pressão venosa central (PVC) tem sido usada por décadas, mas não é confiável, evidências robustas sugerem que seu uso deve ser abandonado. Ao longo dos últimos 15 anos, foram desenvolvidos vários testes dinâmicos, baseados no princípio de alteração da pré-carga cardíaca, usando as interações coração-pulmão, e, consequentemente do débito cardíaco. A elevação passiva das pernas (EPP), a infusão de pequenos volumes de fluidos, a variação da pressão de pulso (ΔPP), as variações nos diâmetros de grandes veias tem sido muito utilizados para avaliação de fluidoresponsividade (FR), neste contexto. Objetivo: Analisar e comparar medidas estáticas e dinâmicas antes, após EPP e após infusão de SF, verificando qual delas apresentam melhor FR. Métodos: Trinta e um pacientes instáveis hemodinamicamente e sob ventilação mecânica (VM) foram incluídos no estudo. Foram avaliados VTIFAO, VTIFMi, IDVCI, ΔPP, PVC, PAM antes de qualquer intervenção, após EPP e após infusão de 500ml SF. As variações dos parâmetros foram calculados para todos os pacientes. Resultados: Após EPP e infusão de SF o VTIFAO aumentou em 10% ou mais em 14 (45%) e 18 (58%) pacientes respectivamente, definidos como FR. A EPP previu a capacidade de resposta a fluidos com uma sensibilidade de 77,7%, especificidade de 100%, valor preditivo positivo de 100% e probabilidade de falso positivo de 0%. O parâmetro utilizado como padrão para FR foi o VTIFAO após SF. A PVC, o IDVCI, o ΔPP, PAM e avaliação médica não se mostraram capazes de avaliar adequadamente FR. Conclusão: Em pacientes instáveis hemodinamicamente e sob VM, a EPP foi capaz de avaliar FR com adequada sensibilidade e especificidade, podendo ser usada com segurança, antes da administração de fluidos.
Introduction: Predictig fluid responsiveness remains a constant challenge for physicians dealing with hemodynamically unstable patients. The use of static parameters, such as central venous pressure (CVP), although used for decades is not a trustworthy source, and the suggestion derived from more robust evidence suggests that the use of such should be abandoned. Over the last 15 years, various dynamic tests have been developed based on the principle of altering the cardiac preload, by using the heart-lung interactions and consequently cardiac output. Hence, Passive Leg Raising (PLR), the intake of small amounts of fluid, the variation of pulse pressure, variations in the diameter of large veins have all been widely used for evaluating fluid responsiveness (FR), within this context. Objective: The underlying objective behind this study was to test, if the non-invasive evaluation with transthoracic echocardiography, the Subaortic velocity time integral (VTI), the Distensibility Index of the Inferior Vena Cava (dIVC), the mitral velocity time integral (MTI), the (CVP) and the change in pulse pressure (ΔPP) after (PLR) and fluid infusion (500ml of saline solution) are able to predict the responsiveness of fluid therapy. Methods: Thirty one hemodynamically unstable patients, under mechanical ventilation (MV) were included in the study. Evaluations were made of VTI, MTI, DIVC), ΔPP and CVP before any intervention, after PLR and after infusion of 500ml saline solution. The variations of the parameters were calculated for all patients. Results: After PLR and infusion of saline solution, the VTI increased by 10% or more in 14 (45%) and 18 (58%) patients, respectively, defined as fluid responders. The PLR predicted a response capacity to fluids with a sensibility of 77,7%, specificity of 100%, a positive predictive value of 100% and a false positive probability of 0%. The CVP, dIVC, ΔPP, PAM and the medical evaluation were not capable of providing an adequate FR evaluation. Conclusion: In hemodynamically unstable patients under MV, PLR were capable of precisely predicting the capacity of FR.
Dissertação (Mestrado)

The dependence of cardiac output measurement precision on ambient temperature and cardiac output stability was assessed by concurrent continuous and bolus thermodilution methods in postoperative cardiac surgery patients. The degree of agreement between the two methods was depended on room temperature (0.1 L/min for each degree below 25 degrees C). The agreement was also closer in trials where cardiac output was stable (< 10% variation). The continuous thermodilution method shows sufficient agreement with the bolus method for use in critical care; however, improved precision of cardiac output thermodilution measurements can be achieved by use of correction factors for cardiac instability and for ambient temperature.

Thesis (Ph. D.)--Michigan State University. Dept. of Electrical and Computer Engineering, 2006.
Title from PDF t.p. (viewed on Nov. 20, 2008) Includes bibliographical references (p. 126-133). Also issued in print.

臂叢阻滯麻醉可以阻斷同側正中神經，尺神經，橈神經和肌皮神經，故其經常被用於上肢手術中麻醉和/或鎮痛。臂叢阻滯麻醉也可以阻滯同側交感神經，導致同側上肢血管擴張（動脈和靜脈）和血流增加。脈沖多普勒超聲技術可以檢測到這些局部的血流動力學變化。文獻回顧表明迄今為止發表的大部分報道片面地評估了臂叢阻滯麻醉後上肢的局部血流動力學變化缺乏全面而系統的研究，並且報道中關於脈沖多普勒超聲技術用於上肢局部血流動力學測量的可靠性和可重復性的數據也很有限。此外，上肢的局部血流動力學變化是否與測量的位置或者使用的臂叢阻滯麻醉技術有關尚且未知。
我假設脈沖多普勒超聲是壹種可靠的測量上肢血流動力學變化的方法，它可以系統地定量測定臂叢阻滯麻醉後上肢的局部血流動力學變化，確定這些變化在上肢不同部位的差異，以及確定不同臂叢阻滯麻醉技術後局部血流動力學變化的差異。以下的部分列舉了本博士課題中開展的壹系列研究來證實我的假設。
第壹，我們在12個健康年輕誌願者中（年齡21-34歲）用脈沖多普勒超聲在上肢肱動脈和指掌側總動脈進行血流動力學測量，評估其在觀察者內和觀察者間的差異性。兩個觀察者獨立進行了測量。測量的指標包括收縮期峰值血流速度（厘米/秒），舒張末期血流速度（厘米/秒），收縮期峰值血流速度和舒張末期血流速度比值，平均速度（厘米/秒），時均速度（厘米/秒），阻力指數，搏動指數，動脈直徑（厘米），和血流量（毫升/分鐘）。結果顯示脈沖多普勒超聲是壹種可靠的方法，可用來重復測量上肢的局部血流動力學參數（組內相關系數>0.9）.
第二，我們在8個病人中（年齡24-70歲）系統地評估了超聲波引導下的腋路臂叢神經阻滯後同側肱動脈的局部血流動力學變化。結果表明臂叢神經阻滯後最早的變化是脈沖多普勒頻譜波形的變化，其波形由三相變為單相，舒張期血流曲線擡升。隨著時間推移，收縮期峰值血流速度，舒張末期血流速度，平均速度，時均速度，動脈直徑，和血流量均顯著增加，收縮期峰值血流速度和舒張末期血流速度比值，阻力指數，搏動指數顯著降低。大部分變化發生在神經阻滯後5分鐘。在所有的局部血流動力學指標中，舒張末期血流速度表現出最顯著的變化（3.7倍），其增加超過收縮期峰值血流速度（1.5倍）和平均速度（2.8倍）。
第三，利用15個病人（年齡23-70歲），我們評估了超聲波引導下的鎖骨上臂叢神經阻滯後上肢近端動脈（肱動脈）和遠端動脈（指掌側總動脈）血流動力學變化的差異。臂叢神經阻滯之後，在能量多普勒圖像上，指掌側總動脈表現出更明顯的血管擴張。在脈沖多普勒頻譜波形中，兩個動脈均出現舒張早期的反流消失以及舒張期曲線擡升。另外，收縮期峰值血流速度，舒張末期血流速度，平均速度，時均速度，動脈直徑，和血流量增加，收縮期峰值血流速度和舒張末期血流速度比值，阻力指數，搏動指數顯著降低。這些指標的相對變化在指掌側總動脈比肱動脈更顯著。此研究中，4個病人出現對側手部溫度的增加，以此推測局部麻醉藥的雙側擴散。
第四，我們開展了壹項前瞻性隨機對照研究來比較腋路和鎖骨上臂叢神經阻滯引起的局部血流動力學變化的不同。兩組病人人口統計學資料類似。兩種臂叢神經阻滯技術均引起肱動脈和指掌側總動脈收縮期峰值血流速度，舒張末期血流速度，平均速度，時均速度，動脈直徑，和血流量的顯著增加，收縮期峰值血流速度和舒張末期血流速度比值，阻力指數，搏動指數顯著降低。跟腋窩方法相比，鎖骨上技術能夠引起肱動脈時均速度和血流量更顯著的增加。然而，在感覺神經阻滯起效方面，腋窩方法比鎖骨上方法更快。
總之，脈沖多普勒超聲可重復地測量肱動脈和指掌側總動脈的血流動力學參數及其變化。臂叢阻滯麻醉引起肱動脈和指掌側總動脈脈沖多普勒頻譜形態的變化，血流速度的增加和血流量的增加。這些局部血流動力學變化在指掌側總動脈中比肱動脈更顯著。鎖骨上臂叢神經阻滯比腋窩方法引起更顯著的局部血流動力學變化。臨床醫生可以利用上肢遠端動脈的局部血流動力學變化來評價臂叢阻滯麻醉的交感神經阻滯效應。麻醉醫師還可以根據這些發現為術後需要較好血流灌註的上肢血管手術選取臂叢神經阻滯方法。
Brachial plexus block (BPB), which produces sensory and motor blockade of the ipsilateral median, ulnar, radial and musculocutaneous nerves, is frequently used for anesthesia and/or analgesia during surgical procedures of the upper extremity. BPB also produces ipsilateral sympathetic nerve blockade that is characterized by vasodilatation (venous and arterial), and an increase in blood flow to the ipsilateral upper extremity. Pulsed wave Doppler (PWD) ultrasound (US) has been used to evaluate these regional hemodynamic changes. A review of the literature shows that most published reports to date have only partially evaluated the regional hemodynamic changes in the upper extremity after a BPB. There are also limited data demonstrating that PWD US is a reliable or reproducible method of quantifying the regional hemodynamic changes in the upper extremity. Moreover, it is also not known whether the regional hemodynamic changes vary with the site of measurement or the technique of BPB used.
I hypothesized that PWD US is a reliable method for measuring regional hemodynamic parameters in the upper extremity. It can be used to comprehensively quantify the regional hemodynamic changes after a BPB and to determine the extent of these changes at different sites in the upper extremity and after different techniques for BPB. The following section outlines a series of studies that I undertook during this PhD project to corroborate my hypothesis.
Firstly, we sought to assess the intra-observer and inter-observer variability of measuring regional hemodynamic parameters, in the brachial and common palmar digital arteries of the upper extremity, using PWD US in 12 healthy young volunteers aged 21-34 yrs. The measurements were performed independently by two observers. Measured hemodynamic parameters included peak systolic velocity (PSV, cm/s), end diastolic velocity (EDV, cm/s), ratio of PSV and EDV (S/D), mean velocity (Vmean, cm/s), time-averaged mean velocity (TAVM, cm/s), resistance index (RI), pulsatility index (PI), the arterial diameter (d, cm), and blood flow (mL/min). The results showed that PWD US is a reliable and reproducible method of measuring regional hemodynamic parameters in the upper extremity (ICC>0.9).
Secondly, we comprehensively evaluated the regional hemodynamic changes in the ipsilateral brachial artery after an ultrasound guided (USG) axillary BPB in eight adult patients aged 24-70 yrs. Our results suggested that the earliest change after the BPB was a change in the morphology of the PWD spectral waveform from a triphasic to a monophasic waveform and an elevation in the diastolic blood flow velocity. Over time, there was also a significant increase in PSV, EDV, Vmean, TAVM, d, and blood flow, and a decrease in S/D ratio, RI, and PI. Most of these changes were seen as early as 5 minutes after the block. The increase in EDV (3.7-fold) was the most notable change, and it was significantly greater than the increase in PSV (1.5-fold) and Vmean (2.8-fold).
Thirdly, the regional hemodynamic changes in the proximal (brachial artery) and distal (common palmar digital artery) artery of the upper extremity after an USG supraclavicular BPB was investigated in 15 adult patients aged 23-70 yrs. After the block, the common palmar digital artery showed more obvious vasodilatation on the power Doppler US scan. In the PWD spectral waveform, and in both arteries studied, the protodiastolic blood flow disappeared and there was an elevation of the diastolic curve. Also there was a significant increase in PSV, EDV, Vmean, TAVM, d, and blood flow, and a significant reduction in S/D ratio, PI and RI in both arteries. Relative changes of these parameters were greater in the common palmar digital artery than in the brachial artery. In this study, bilateral spread of local anesthetic was observed in 4 patients, as evidenced by an increase of skin temperature on the contralateral hand.
Fourthly, a prospective and randomized study was conducted to compare the regional hemodynamic changes in the upper extremity after an axillary and supraclavicular BPB. The two study groups were similar with respect to demographic data. Both axillary and supraclavicular BPB caused a significant increase in PSV, EDV, Vmean, TAVM, d, and blood flow, and a significant reduction in S/D ratio, PI and RI in both the brachial and common palmar digital arteries. Compared with the axillary approach, the supraclavicular approach produced significantly greater increases in TAVM and blood flow in the brachial artery. However, the onset of sensory blockade was faster after the axillary BPB than with the supraclavicular BPB.
In conclusion, PWD US is a reliable and reproducible method for quantifying the regional hemodynamic parameters in both the brachial and common palmar digital arteries. BPB produces a change in the morphology of the PWD spectral waveform, arterial vasodilatation, an increase in blood flow velocity, and an increase in blood flow in both the ipsilateral brachial and common palmar digital arteries. These changes in regional hemodynamic parameters were more profound in the common palmar digital artery than in the brachial artery. Also these changes were more significant after a supraclavicular BPB than after an axillary BPB. These findings will allow clinicians to evaluate the sympathetic effect of a BPB using regional hemodynamic changes in the distal arteries of the upper extremity. These findings will also allow anesthesiologists to make an evidence-based choice on the techniques of BPB for vascular surgery of the upper extremity when good tissue perfusion is desirable postoperatively.
Detailed summary in vernacular field only.
Detailed summary in vernacular field only.
Detailed summary in vernacular field only.
Detailed summary in vernacular field only.
Detailed summary in vernacular field only.
Detailed summary in vernacular field only.
Detailed summary in vernacular field only.
Li, Jiawei.
Thesis (Ph.D.)--Chinese University of Hong Kong, 2012.
Includes bibliographical references (leaves 182-192).
Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web.
Abstract also in Chinese.
TABLE OF CONTENTS
ABSTRACT
中文摘要
STATEMENT OF WORK
ACKNOWLEDGMENTS
PUBLICATIONS AND PRESENTATIONS
LIST OF ABBREVIATIONS
LIST OF TABLES
LIST OF FIGURES
Chapter CHAPTER 1 --- Introduction
Chapter 1.1 --- Introduction
Chapter 1.2 --- Aims of the project
Chapter 1.3 --- Outline of the thesis
Chapter CHAPTER 2 --- Literature Review
Chapter 2.1 --- Introduction
Chapter 2.2 --- Why regional hemodynamic changes occur after a BPB
Chapter 2.2.1 --- Anatomy of the sympathetic nervous system in the upper extremity
Chapter 2.2.2 --- The anatomic relationship between the sympathetic nerves and the brachial plexus
Chapter 2.2.3 --- Sympathetic efferents to blood vessels in the upper extremity
Chapter 2.3 --- Methods used to measure regional hemodynamic changes
Chapter 2.3.1 --- Skin and muscle blood flow
Chapter 2.3.2 --- Regional hemodynamic measurements using PWD US
Chapter 2.3.2.1 --- Basics of Doppler ultrasound
Chapter 2.3.2.2 --- Principles of blood flow
Chapter 2.3.2.3 --- Spectral analysis of blood flow using PWD US
Chapter 2.4 --- Published data on regional hemodynamic changes after BPB
Chapter 2.4.1 --- Skin temperature
Chapter 2.4.2 --- Cutaneous and muscular blood flow
Chapter 2.4.3 --- Regional hemodynamic measurements on major arterial branches of the upper extremity
Chapter 2.5 --- Introduction of BPB
Chapter 2.5.1 --- Anatomy of the brachial plexus
Chapter 2.5.2 --- Techniques for performing BPB
Chapter 2.5.3 --- USG BPB
Chapter 2.5.3.1 --- History
Chapter 2.5.3.2 --- Advantages of ultrasound guidance for peripheral nerve blockade
Chapter CHAPTER 3 --- Methodology
Chapter 3.1 --- Introduction
Chapter 3.2 --- Patient preparations
Chapter 3.3 --- Regional hemodynamic measurement
Chapter 3.3.1 --- Ultrasound equipment
Chapter 3.3.2 --- Patient position
Chapter 3.3.3 --- Regional hemodynamic measurements using PWD US
Chapter 3.3.3.1 --- Optimizing settings for B-Mode US
Chapter 3.3.3.2 --- Optimizing settings for PWD US
Chapter 3.3.3.3 --- Measurement of regional hemodynamic parameters
Chapter 3.3.4 --- Measurement of diameter (d) and blood flow (Q)
Chapter 3.4 --- USG BPB
Chapter 3.4.1 --- USG axillary BPB
Chapter 3.4.1.1 --- Scout scan
Chapter 3.4.1.2 --- Aseptic precautions
Chapter 3.4.1.3 --- USG axillary BPB
Chapter 3.4.2 --- USG supraclavicular BPB
Chapter 3.4.2.1 --- Scout scan
Chapter 3.4.2.2 --- Aseptic precautions
Chapter 3.4.2.3 --- USG supraclavicular BPB
Chapter 3.5 --- Outcome data after the BPB
Chapter CHAPTER 4 --- Measurement of Regional Hemodynamic Parameters in the Upper Extremity Using Pulsed Wave Doppler Ultrasound: A Reliability Study
Chapter 4.1 --- Introduction
Chapter 4.2 --- Methods
Chapter 4.2.1 --- Subjects
Chapter 4.2.2 --- Study design
Chapter 4.2.3 --- Data acquisition
Chapter 4.2.4 --- Statistical analysis
Chapter 4.3 --- Results
Chapter 4.4 --- Discussion
Chapter 4.4.1 --- Summary of main findings
Chapter 4.4.2 --- Compared with previous studies
Chapter 4.4.3 --- Sources of measurement variability
Chapter 4.4.4 --- Explanation for the variation in the changes in various regional hemodynamic parameters
Chapter 4.5 --- Conclusion
Chapter CHAPTER 5 --- Regional Hemodynamic Changes after an Axillary BPB: A Pulsed Wave Doppler Ultrasound Study
Chapter 5.1 --- Introduction
Chapter 5.2 --- Methods
Chapter 5.2.1 --- Patient enrollment
Chapter 5.2.2 --- Patient preparation
Chapter 5.2.3 --- Measurement of baseline regional hemodynamic parameters
Chapter 5.2.4 --- USG axillary BPB
Chapter 5.2.5 --- Outcome data after the BPB
Chapter 5.2.6 --- Sensory and motor assessments after the BPB
Chapter 5.2.7 --- Statistical Analysis
Chapter 5.3 --- Results
Chapter 5.4 --- Discussion
Chapter 5.4.1 --- Summary of main findings
Chapter 5.4.2 --- Limitations
Chapter 5.4.3 --- Changes in PWD spectral waveform
Chapter 5.4.4 --- Changes in regional hemodynamic parameters
Chapter 5.4.5 --- Increase in skin temperature
Chapter 5.4.6 --- Effects of local anesthetic
Chapter 5.5 --- Conclusion
Chapter CHAPTER 6 --- Does a Supraclavicular Brachial Plexus Block Induce Comparable Hemodynamic Changes in the Proximal and Distal Arteries of the Upper Extremity?
Chapter 6.1 --- Introduction
Chapter 6.2 --- Methods
Chapter 6.2.1 --- Patient recruitment
Chapter 6.2.2 --- Patient preparation
Chapter 6.2.3 --- Measurement of baseline regional hemodynamic parameters, arterial diameter and blood flow
Chapter 6.2.4 --- USG supraclavicular BPB
Chapter 6.2.5 --- Outcome measurements after the BPB
Chapter 6.2.6 --- Statistical analysis
Chapter 6.3 --- Results
Chapter 6.4 --- Discussion
Chapter 6.4.1 --- Summary of the main findings
Chapter 6.4.2 --- Limitations
Chapter 6.4.3 --- Changes in the PWD spectral waveform
Chapter 6.4.4 --- Explanation of the differences in regional hemodynamic changes in the distal and proximal arteries after BPB
Chapter 6.4.5 --- Increase in skin temperature and its relation to blood flow
Chapter 6.4.6 --- Bilateral sympathetic effect after supraclavicular BPB
Chapter 6.4.7 --- Other findings of this study
Chapter 6.5 --- Conclusion
Chapter CHAPTER 7 --- Does a Supraclavicular Brachial Plexus Block Induce Greater Changes in Regional Hemodynamics than an Axillary Brachial Plexus Block?
Chapter 7.1 --- Introduction
Chapter 7.2 --- Methods
Chapter 7.2.1 --- Sample size estimation
Chapter 7.2.2 --- Exclusion criteria
Chapter 7.2.3 --- Randomized allocation
Chapter 7.2.4 --- Preparations before the ultrasound scan
Chapter 7.2.5 --- Measurement of baseline regional hemodynamic parameters, diameter and blood
Chapter 7.2.6 --- USG axillary and supraclavicular BPB
Chapter 7.2.7 --- Outcome measurements after the BPB
Chapter 7.2.8 --- Statistical analysis
Chapter 7.3 --- Results
Chapter 7.4 --- Discussion
Chapter 7.4.1 --- Summary of the main findings
Chapter 7.4.2 --- Limitations
Chapter 7.4.3 --- Change in the PWD spectral waveform
Chapter 7.4.4 --- Differences in regional hemodynamic changes between the 2 study groups
Chapter 7.4.5 --- Differences in sensory and motor blockade between the 2 study groups
Chapter 7.4.6 --- Changes in skin temperature
Chapter 7.5 --- Conclusion
Chapter CHAPTER 8 --- Summary and Conclusions
APPENDIX
REFERENCES

Trabalho Final do Curso de Mestrado Integrado em Medicina, Faculdade de Medicina, Universidade de Lisboa, 2021
A monitorização hemodinâmica é um dos pilares da Medicina Intensiva que fornece informação útil sobre o estado do sistema cardiovascular do doente. A medição do débito cardíaco de um doente em choque permite a avaliação de outras variáveis importantes como a entrega de oxigénio e a perfusão tecidular. A abordagem inicial do doente em choque séptico consiste, entre outras atitudes, na ressuscitação hemodinâmica com bólus de fluídos. No entanto, nas fases seguintes do tratamento é necessário avaliar a necessidade de expansão de volume. O objetivo principal desta revisão narrativa é descrever os métodos de monitorização hemodinâmica utilizados atualmente e destacar as principais indicações e limitações de cada aparelho. A base de dados utilizada durante a pesquisa bibliográfica foi o Pubmed, tendo sido selecionados 73 artigos. Nesta revisão são mencionados vários métodos, incluindo o cateter arterial pulmonar, técnica de termodiluição transpulmonar, ecocardiograma, análise de contorno do pulso arterial, bioimpedância e bioreactância. A capacidade destes aparelhos determinarem a condição fluidorespondedora em doentes com choque séptico é discutida durante todo o trabalho. Os parâmetros dinâmicos, incluindo a variação da pressão de pulso e a variação do volume sistólico obtidos através da análise de contorno de pulso, são considerados bons preditores da condição fluidorespondedora. Pelo contrário, variáveis estáticas como a pressão venosa central podem ser utilizadas como indicadores da pré-carga, mas não preveem se o débito cardíaco vai aumentar em resposta a um bólus de fluídos. Os médicos devem conhecer os mecanismos básicos por detrás destes aparelhos, de modo a utilizá-los de forma correta, prevenindo assim possíveis consequências decorrentes da administração excessiva de fluidos. A criação de protocolos sobre métodos de monitorização pode contribuir para uniformizar a abordagem inicial.
Hemodynamic monitoring is one of the cornerstones of Intensive Care that provides useful information regarding the patient’s cardiovascular state. Assessment of cardiac output in patients with septic shock allows the evaluation of other important variables like oxygen delivery and tissue perfusion. The initial approach in septic shock involves an initial hemodynamic resuscitation with fluid bolus, among other approaches. However, it’s necessary to evaluate the need for fluid expansion during the following phases of treatment. The main purpose of this narrative review is to describe the currently available hemodynamic monitoring devices and to point out the main indications and limitations of each device. The database used during the literary research was Pubmed, with 73 articles being included in this review. In this review are mentioned several methods, including the pulmonary artery catheter, transpulmonary thermodilution technique, arterial pulse contour analysis, echocardiogram, bioimpedance and bioreactance. The capacity of these devices in predetermining fluid responsiveness in patients with septic shock is discussed during the course of this review. Dynamic parameters, including pulse pressure variation and stroke volume variation obtained by pulse contour analysis, are considered good predictors of fluid responsiveness. On the contrary, static variables such as central venous pressure may be used as preload indicators, but cannot predict if cardiac output will increase in response to a fluid bolus. Clinicians should understand the basic mechanism in which these devices operate in order to correctly use them and prevent possible consequences of fluid overload. The creation of hemodynamic devices protocols could help standardize the initial monitoring approach in septic patients.

碩士
高雄醫學大學
公共衛生學研究所碩士在職專班
92
OBJECTIVES: The purpose of this study is to analyze the usage of three invasive hemodynamic monitoring devices in patients receiving coronary artery bypass graft (CABG), to understand the decision-making and clinical outcome in choosing among Central Venous Pressure catheter（CVP）, Pulmonary Artery Catheter（PAC）, and Fiberoptic Pulmonary Artery Catheter. METHODS: Records of 116 CAD patients who received CABG in a regional teaching hospital from Jan. 2000 to Dec 2003, and records of 662 CABG cases from sampling of National Health Insurance Research Database were retrieved. Variables such as the demographic data, disease severity, co-morbidity, hemodynamic monitoring devices, medical cost and length of stay in each admission, length of stay in Intensive Care Unit (ICU), mortality rate during admission, and readmission rate within 14 days were analyzed. RESULTS: In the regional hospital no significant correlation of patients attributes to the choice of monitoring device was noted, the odds ratio of death in admission were higher among patients on CVP (4.66) or with preoperative acute myocardial infarction events (9.38 ). There was a down hill trend of usage of PAC with surge in usage of both CVP and fiberoptic PAC. The private hospital perform good clinical outcome in CVP group with lower mortality and low total hospital fee in case payment CABG. CONCLUSION: The usage of three invasive hemodynamic monitoring devices in CABG surgery is safe. It is up to the professional training background and personal preference of the anesthesiologists and cardiac surgeons. This study indicates that the regional hospital and public hospital should restrain from usage of CVP for hemodynamic monitoring in CABG till there is new evidence available to make change.

Worldwide, at least 200 million people are affected by peripheral vascular diseases (PVDs), including peripheral arterial disease (PAD), chronic venous insufficiency (CVI) and deep vein thrombosis (DVT). These diseases have considerable socioeconomic impacts due to their high prevalence, cost of investigation, treatment and their effects on quality of life. PVDs are often undiagnosed with up to 60% of patients with PVD remaining asymptomatic. Early diagnosis is essential for effective treatment and reducing socioeconomic costs, particularly in patients with diabetes where early endovascular treatment can prevent lower extremity amputation. However, available diagnostic methods simply do not meet the needs of clinicians. For example, duplex ultrasound or plethysmography are time-consuming methods, costly and require access to highly trained clinicians. Due to the cost and time requirements of such methods, they are often reserved for symptomatic patients. On the other hand, the Ankle Brachial Index (ABI) test is cheap but has poor sensitivity for those patients with diabetes and the elderly, both growing high-risk populations. There is an urgent need for new diagnostic tools to enable earlier intervention. Researchers at the MARCS Institute have developed a novel hemodynamic monitor platform named HeMo, specifically for the assessment of peripheral blood flow in the leg. This development aimed to provide a fast and low-cost diagnosis of both peripheral arterial disease and chronic venous insufficiency. This work first provides a comprehensive literature review of the existing non-invasive diagnostic devices developed since 1677 to highlight the need of development of a new blood monitoring tool. Second, it presents the simplified circuit of the HeMo device and provides series of pilot experiments with HeMo demonstrating its potential for diagnosis of both peripheral arterial disease and chronic venous insufficiency. Third, it presents a quantitative characterisation of the electrical behaviour of the electro-resistive band sensors with the development of an expansion/contraction simulator rig and using spectral analysis. The characterisation of the electro-resistive band was essential to understand the nonlinear electrical behaviour of such sensors and would be of interest for other users and uses of the electro-resistive band sensors. However, in another perspective this sinusoidal linear stretching movement and the presented method shows an example for the application of the presented rig, highlighting that the same technique could be used for characterisation of similar stretchable sensors. Fourth, it shows data from a healthy population, assessing the performance of HeMo compared to light reflection rheography (LRR sensor-VasoScreen 5000) for the assessment of venous function. Fifth, it presents human study data where the performance of HeMo is compared to photoplethysmography (PPG sensor-VasoScreen 5000) for the evaluation of the arterial function. Overall, the presented work here, steps toward development of the final version of a novel hemodynamic monitoring device, and its validation.

Lowering of central venous pressure in hepatic surgery is nowadays widely recommended and used procedure. Low central venous pressure anesthesia is associated with decreased blood loss and improved clinical outcome. There are several approaches how to reach low central venous pressure. Till now none of them is recommended as superior in terms of patient safety and clinical outcome. Concurrently there is still debate if to use the low central venous pressure anesthesia principle or if it could be replaced with a principle of anesthesia with high stroke volume variation (or another dynamic preload parameter) with the use of a more sophisticated hemodynamic monitoring method. Results of our study didn't show any significant difference between two approaches used for reduction of central venous pressure, but suggest that the principle of low central venous pressure anesthesia could be possibly replaced by the principle of high stroke volume variation anesthesia which presumes the use of advanced hemodynamic monitoring. KEYWORDS Hepatic resection, central venous pressure, Pringle maneuver, hemodynamics, hemodynamic monitoring, fluid therapy, anesthesia

Early deterioration and long-term recurrence were common after stroke or transient ischemic attach (TIA), however, it is unclear whether they were correlated with active embolization and the consequent new cerebral infarct in acute phase. By employing TCD and diffusion weighted imaging (DWI), we studied the significance of the progression of MES and infarcts during acute phase on the clinical outcomes. We found that the disappearance of MES was correlated with better improvement on day 7 of recruitment; for the long-term outcome, occurrence of exacerbating infarct tended to predict recurrent stroke. Treatment aiming to reduce MES and prevent infarct exacerbation in acute phase may improve the prognosis after stroke.
Finally, one study was performed to assess the changes of hemodynamic parameters after stenting of severe stenosis in the MCA. We aimed to investigate whether TCD can reflect the lumen changes after revascularization and detect hyperperfusion. The findings showed that the velocity of stented MCA in most patients normalized within 24 hours after procedure, but the role of TCD in detecting restenosis in long run needed to be verified; no one suffered from hyperperfusion during the period of our study. The long-term outcomes of patients with normalized velocity versus those with persistently high velocity needed to be further studied. Apart from the velocity changes, changes of the collateral flow after intervention may also be an important part of hemodynamic changes. (Abstract shortened by UMI.)
It was suggested that anti-platelet therapy can reduce the MES, but little was known about the efficacy of low molecular weight heparin (LMWH) although in theory LMWH can reduce the red fibrin-dependent thromboemboli. As a sub-analysis of Fraxiparine in Ischemic Stroke (FISS)-tris study, our study did not show advantages of LMWH in eliminating MES compared with aspirin.
Previous studies showed the accuracy of TCD in diagnosis of middle cerebral artery (MCA) stenosis was variable and the positive predictive value (PPV) was less than 50% in a recent report. One of the important reasons was that most criteria were based on the velocity-only method, ignoring other non-velocity information. Thus, we tried to establish new diagnostic criteria by means of designing an assessment form which integrated more characteristics apart from the velocity acceleration. A composite score for each MCA was calculated according to following parameters in the form: Velocity Scale (score 0-6 for peak systolic velocities<140 to ≥300cm/s), Hemodynamic Scale (score 0-5 for focal or diffuse velocity increase; score 0-6 for differences between bilateral MCA; score 17 for damping velocity), Spectrum Scale (score 0-2 for normal spectrum, turbulence and musical murmurs). Our results showed that compared with the previously reported criteria, the score calculated from the assessment form yielded much more balanced accuracy against magnetic resonance angiography (MRA) and digital subtraction angiography (DSA). However, the composition of the assessment form was only based on personal experience and need to be further modified. Multicenter studies with large sample size are also needed to confirm the advantages of this new method.
Second, we performed three studies to investigate the relationship between the progression of MES and the short or long-term outcome and the relationship between MES and different treatments.
Hao, Qing.
Adviser: Ka Sing Wong.
Source: Dissertation Abstracts International, Volume: 70-06, Section: B, page: 3419.
Thesis (Ph.D.)--Chinese University of Hong Kong, 2008.
Includes bibliographical references (leaves 155-181).
Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web.
Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web.
Abstracts in English and Chinese.
School code: 1307.

Since the advent of functional magnetic resonance imaging (fMRI) and the rise in popularity of its use for resting state functional connectivity mapping (rs-FCM) to non-invasively detect correlated networks of brain activity in human and animal models, many resting state FCM studies have reported differences in these networks under pathologies such as Alzheimer’s or schizophrenia, highlighting the potential for the method’s diagnostic relevance. A common underlying assumption of this analysis, however, is that the blood oxygen level dependent (BOLD) signal of fMRI is a direct measurement of local neural activity. The BOLD signal is in fact a measurement of the local changes in concentration of deoxy-hemoglobin (HbR). Thus, it is imperative that neurovascular coupling—the relationship between neuronal activity and subsequent hemodynamic activity—be better characterized to enable accurate interpretation of resting state fMRI in the context of clinical usage. This dissertation first describes the development and utility of WFOM paradigm for the robust and easily adaptable imaging of simultaneous neuronal and hemodynamic activity in awake mouse models of health or disease in strains with genetically encoded fluorescent calcium reporters. Subsequent exploration of resting state WFOM data collected in Thy1-GCaMP3 and Thy1-GCaMP6f mouse strains is then presented, namely the characterization of spatiotemporal patterns of neuronal and hemodynamic activity and different modulatory depths of neuronal activity via a toolbox of unsupervised blind source separation (e.g. k-means clustering) and supervised (e.g. non-negative least squares, Pearson correlation) analysis tools. The presence of these different modulatory depths of neuronal activity were then confirmed in another Thy1-jRGECO1a mouse strain using the same imaging scheme. Finally, the dissertation documents the application of the WFOM paradigm and select analysis tools to a novel mouse model of diffusely infiltrating glioma, through which neuronal and hemodynamic activity changes during diffusely infiltrating glioma development which impact temporal coherence of the tumor region activity relative to non-tumor regions activity were recorded and analyzed. The paradigm also allowed for recording of numerous spontaneous occurrences of interictal neuronal activity during which neurovascular coupling is modified in the tumor, as well as occurrences of non-convulsive generalized seizure activity (during which neurovascular is non-linear and cortex eventually suffers hypoxia). The detection of spatiotemporal patterns and different modulatory depths of activity in the awake mouse cortex, as well as observation of changes in functional activity in the context of diffusely infiltrating glioma, provide us with new insights into the possible mechanisms underlying variations in resting state connectivity networks found in resting state fMRI studies comparing health and disease states.

博士
國立臺灣師範大學
體育學系
105
Obesity is likely to lead to cardiovascular disease and poor physical fitness (PF), and increase physical activity (PA) and reduce energy intake are the principles of weight control. However, few previous study designing negative energy balance monitoring system to control body weight and observe the cardiovascular performance. OBJECTIVE: This study was to investigate the effects of 12-week different proportion of negative energy balance monitoring interventions on PF and cardiac hemodynamic in young obese women. METHODS: The 53 healthy young obese women (mean age 21.72 ± 1.78; BMI 29.61 ± 3.42) were recruited and randomly assigned to the Calories Restriction Monitor (CRM, 100% diet negative balance), the PA Monitor (PAM, 100% PA negative balance), the Calorie Restriction and PA Monitor (50% CRM + 50% PAM negative balance, CPM) and control group (CG). The CRM, PAM, CPM experimental groups were undergone 12-week intervention with 0.5 kg weight loss per week. The PF and cardiac hemodynamic variables of all the subjects were assessed at week 0 (stage 1), 7 (stage 2) and 13 (stage 3). All the collected data collected were analyzed with Two-Way Mixed ANCOVA, Repeat t test and One-Way ANOVA. RESULTS: 1. Stage and group differences: In stage 3, Weight(W), Body Mass Index(BMI), Fat%, Waist Circumference(WC), Hip Circumference (HC), Endurance Index (EI) of CPM group was significantly better than that of CG. 2. Before and after difference: (1) Body composition: The W, BMI, Fat Free Mass(FFM) and Waist Circumference(WC), HC of CRM, PAM, CPM groups; the Fat% of PAM and CPM groups; and the Waist-Hip Ratio(WHR) of CG and CPM groups all improved significantly after intervention. (2) Physical Ability: The 6-minute walking distance (WD_6min) of CRM, PAM, CPM groups; Long Jump (LJ), EI of CRM and CPM groups; the Curl Ups for 60 seconds (CU60s) of PAM and CPM groups all had improved significantly after intervention. (3) The Cardiac Hemodynamics: The Stroke Volume (SV), Stroke Volume Index (SVI), End Systolic Volume, Left ventricle Ejection Fraction% of PAM group in 1-3 stage; and the SV, SVI of PAM group in 2-3 stage were all improved significantly. 3. Difference volume change (_D)before and after intervention: (1) Body Composition: The W_D, BMI_D, FAT% _D, WC_D, HC_D of CRM, PAM, CPM groups; the Waist-hip Ratio_D (WHR_D) of CPM were all significantly higher than that of CG group. (2) Physical Ability: The CU60s_D of PAM group; the EI_D of CRM, CPM groups; the WD_6min_D of CRM, PAM, CPM groups were all significantly better than that CG group. CONCLUSION: Most of the PF and body composition of 3 experimental groups with different proportion of same negative energy balance were improved after 12-week intervention. However, Only the PAM group had showed the positive effects on cardiac hemodynamic functions, more physical activity may require for better the cardiac dynamic function during weight loss program.

Peng Zhiyong.
"December 2004."
Thesis (Ph.D.)--Chinese University of Hong Kong, 2004.
Includes bibliographical references (p. 146-175)
Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web.
Mode of access: World Wide Web.
Abstracts in English and Chinese.

Beneš J.: HEMODYNAMIKA V ČASNÉ FÁZI KRITICKÝCH STAVŮ A PERIOPERAČNÍ MEDICÍNĚ - Využití méně invazivních monitorovacích prostředků k cílené hemodynamické péči ABSTRACT Hemodynamic instability occurs very often in critically ill patients and during the perioperative period. Insufficiency in the preload, contractility and afterload contribute in major part to this phenomenon. Hemodynamic monitoring allows clinicians to recognize and to intervene early the underlying cause. Due to new technologies development in recent years it is possible to provide continuous monitoring of hemodynamic parameters with diminished invasivity. Hemodynamic optimization and goal directed therapy show treatment benefit in some groups of critically ill patients and mainly during the perioperative period. Aim of hemodynamic optimizations is to attain the best obtainable hemodynamic conditions with use of fluid loading and inotropic support. In many studies in recent years goal-directed therapy was associated with morbidity and mortality reduction. According to the results of our clinical research hemodynamic optimization using stroke volume variation and minimally invasive device based on the pressure wave analysis is feasible and show the same results as other works with more invasive devices. Key words Hemodynamic monitoring,...

This diploma thesis focuses on the monitoring of hemodynamics in intensive care units; the main objective was to create an educational material for newly employed nurses. This educational material should facilitate the adaptation process of nurses at Anaesthesiology-Resuscitation Units (AR) or Intensive Care Units (ICU).The diploma thesis is divided in two parts: theoretical and empirical. The topics covered by the theoretical part include the concept of intensive care, the technical equipment, the scope of work of intensive care nurses, anatomy and physiology of the cardiovascular system, cardiovascular system monitoring, hemodynamic monitoring, adaptation of new nurses at the workplace, and the possibilities of educational methods aimed at newly employed nurses. The empirical part was conducted as qualitative inquiry in the form of interview. The interviews were semi-standardised and they were held at the AR unit in the České Budějovice Hospital. The subjects were the nurses from the RES 1 and RES 2 stations. The first part of the research inquiry consisted in interviews with the nurses at the Anaesthesiology-Resuscitation unit. The interviews were not taped, due to the respondents' request. All the answers were carefully recorded and immediately transcribed and processed to prevent any inaccuracy of information. The results were organised in charts according to the categorisations, in a well-arranged manner. The second phase consisted in creating the educational material for the newly employed nurses and the third phase concluded the project by distributing the educational materials at the hospital unit where the interviews were conducted. The nurses could therefore assess whether the educational material meets their requirements and will be useful in practice. The respondents were interviewed again and the results were subsequently also organised in charts.The results of the research inquiry show that the nurses at the Anaesthesiology-Resuscitation Unit in the České Budějovice Hospital perceive the correct hemodynamic monitoring as important, that they know what hemodynamic monitoring is and are aware of the monitoring possibilities. The nurses of this unit perform both invasive and non-invasive monitoring of hemodynamic parameters. The basic task is measuring the central venous pressure and arterial pressure. Other parameters are monitored by the doctors with the application of the Swan-Ganz catheter. The most frequently used monitors are PICCO, Lidco, Vigileo and Vigilance. All interviewed respondents agreed that their only help during the adaptation process was the manufacturers' materials and the advice from the nurse-trainers. A small part of the respondents was trained directly by the company distributing the monitors. The final phase of the research inquiry revealed that the nurses like the new educational material but they are afraid that it will end up collecting dust as the other materials supplied by students. The interviews established that it is easier to directly communicate the necessary information to the new nurses along with practical demonstration than to recommend an educational material for studying of at least the theoretical part.

The roles of the vascular architecture and blood flow in response to neurovascular diseases are important in predicting physiological outcomes. Observing these parameters chronically with optical imaging techniques provides insight into the neurovascular recovery process. We develop and deploy optical imaging systems for monitoring the progression of vascular structure, perfusion, and functional blood response after ischemic stroke in a chronic rodent model to observe vascular dynamics of the cortex under normal and diseased pathologies. Specifically, we monitor the progression of the vascular structure and cerebral blood flow (CBF) over a chronic period in the rodent cortex after photo-thrombotic occlusion. Multi-Exposure Speckle Imaging (MESI) provides surface measurements of microvascular flow dynamics while Two-Photon Fluorescence Microscopy offers direct visualization of the microvascular structure. We observe the occurrence of vascular reorientation in the sub-surface microvascular structure over a 35 day post-occlusion period. We also correlate MESI flow estimates in the parenchyma with sub-surface microvascular volume fractions from two-photon microscopy to assess how vascular density influences the surface-integrated MESI measurements. Next, we develop and validate a MESI technique for measuring absolute changes of the functional blood flow response to forepaw stimulation in rodents, termed FA MESI. The optimal camera exposures for capturing the CBF response to forepaw stimulation are extracted from a training set of animal data and the feasibility of the technique is demonstrated in a testing animal set by comparing functional response results between new and existing techniques. We then deploy this system in a chronic study monitoring the progression of hemodynamic parameters after ischemic stroke within the functionally responding area of the cortex. The progression of the regional CBF perfusion and absolute changes in the magnitude of the functional blood flow response are monitored chronically after photo-thrombotic occlusion. We compare the differences between absolute and relative measurements of the functional blood flow responses, and validate FA MESI by comparing baseline measurements to 15-exposure MESI over the sampled flow distributions. We demonstrate the differences measured between the functional outcomes and the regional CBF perfusion over a three week post-occlusion time period.
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Neoadjuvant chemotherapy (NAC) is increasingly being utilized to reduce tumor burden prior to surgery for breast cancer patients with stage II or higher disease. A pathologic complete response (pCR) to NAC has been correlated with longer 5-year survival and is generally considered as an absence of invasive cancer in the breast and axillary nodes at the time of surgery. Unfortunately, only about 10% of patients achieve pCR during NAC, and it may take months after the first infusion to determine response with methods that rely on anatomic information, such as palpation, mammography, ultrasound, and MRI. Functional imaging technologies such as Positron Emission Tomography, Magnetic Resonance Spectroscopy, and more recently, Diffuse Optical Spectroscopy, have shown promise for earlier predictions of therapy response. However, most of these techniques suffer from high expense, lack of portability, and safety issues related to the use of ionizing radiation or exogenous contrast agents. Furthermore, the repeated patient visits required by these techniques may hamper their clinical adoption for this purpose. This project aims to develop a new wearable diffuse optical device that can be used to investigate if very early timepoints during a patient’s first chemotherapy infusion are predictive of overall response (pCR versus non-pCR) to NAC. These timepoints correspond to an already scheduled patient visit and have so far been unexplored for their prognostic value. The development of this continuous-wave diffuse optical imaging device was conducted in three stages. First, a prototype rigid probe was designed and developed to test key optical and electrical components. Second, a high optode-density flexible probe was design and fabricated which can conform to the curved surface of the human breast. Finally, a control box with miniaturized electronics and high-speed electronics was designed and fabricated to complete a clinic-ready system. This system was then tested in both the laboratory setting and as part of a normal-volunteer clinical study in healthy subjects during a breath hold hemodynamic challenge.
2019-10-22T00:00:00Z

The diploma thesis deals with non-invasive and invasive monitoring of the cardiovascular system, focusing on non-medical health workers. The aim of the work was to analyze the knowledge of non-medical health workers in selected areas of cardiovascular monitoring. The data was obtained in the form of a non- standardized questionnaire created by myself. For the research were selected non-medical health workers working in Prague hospitals in coronary units and postoperative cardiac surgery units. The total number of respondents who participated in the research was 108. The results of the survey revealed that non-medical staff are relatively well versed in the issue of cardiovascular monitoring. A rather surprising finding was that most respondents did not use foreign literature to study cardiovascular monitoring. As part of the comparison of the respondents, the better knowledge of cardiovascular monitoring was presented in non-medical staff of the Department of Postoperative Cardiac Surgery. Compared in relation to the highest educational attainment, university graduates have demonstrated a higher level of knowledge than others. Based on achieved data, it was created a study text for newcomers, which contains basic information for better orientation in the given issue. keywords: cardiovascular...

Indiana University-Purdue University Indianapolis (IUPUI)
The passive properties of the venous wall are important in the development of venous pathology. Increase in venous pressure due to retrograde flow (reflux) and obstruction of venous flow by intrinsic and extrinsic means are the two possible mechanisms for venous hypertension. Reflux is the prevailing theory in the etiology of venous insufficiency. The objective of this thesis is to quantify the passive biomechanical response and structural remodeling of veins subjected to chronic venous reflux and hypertension. To investigate the effects of venous reflux on venous mechanics, the tricuspid valve was injured chronically in canines by disrupting the chordae tendineae. The conventional inflation-extension protocol in conjunction with intravascular ultrasound (IVUS) was utilized to investigate the passive biomechanical response of both control common iliac veins (from 9 dogs) and common iliac veins subjected to chronic venous reflux and hypertension (from 9 dogs). The change in thickness and constituent composition as a result of chronic venous reflux and hypertension was quantified using multiphoton microscopy (MPM) and histological evaluation. Biomechanical results indicate that the veins stiffened and became less compliant when exposed to eight weeks of chronic venous reflux and hypertension. The mechanical stiffening was found to be a result of a significant increase in wall thickness (p < 0.05) and a significant increase in the collagen to elastin ratio (p < 0.05). After eight weeks of chronic reflux, the circumferential Cauchy stress significantly reduced (p < 0.05) due to wall thickening, but was not restored to control levels. This provided a useful model for development and further analysis of chronic venous insufficiency and assessment of possible intervention strategies.