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1
Rodmell, Paul Irvin. "A novel oximeter." Thesis, University of Nottingham, 2006. http://eprints.nottingham.ac.uk/31151/.
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The measurement of oxygen saturation SO2 is one of the vital signs relied on by the medical profession. Pulse oximeters are widely used in many branches of medicine; and are the most widely used method of assessing oxygen saturation. However they can only be applied to an extremity (usually a finger or toe), need calibration, and are known to be inaccurate under certain conditions. The object of this research was to develop an oximeter, that does not require a pulsatile signal, (and so can be used anywhere on the body); can be used in either transmission of reflective mode; does not require calibration; and does not suffer from the known problems of pulse oximeters. The instrument must work with reflected light, and so the first step was to develop a Monte Carlo simulation of the Attenuation spectra, for visible light, from a scattering media (tissue). A mathematical model of the attenuation surface had then to be found, and its effect on the absorbtion spectra of oxyhemoglobin HbO2 and de-oxyhemoglobin Hb understood. Then the oxygen saturation the ratio of HbO2 to total haemoglobin could be recovered. Methods of computing oxygen saturation from the raw reflectance spectra were devised and then tested with single reflection spectra, the results indicate that a low cost instrument could be developed. The technique was applied to images from a hyper-spectral camera, this instrument takes a full spectrum at each pixel of an image, and enabled an oxygen saturation map for large areas of the body to be produced. The technique is being used with AstraZenca Ltd as a bio marker skin for irritation studies.
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Clark, Daniel John. "A spectroscopically based blood oximeter." Thesis, Northumbria University, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.335573.
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Sankman, Joseph, Brian Bailey, Brian Ebel, Scott Galvin, Jack Grantham, Scott Little, Erica Morey, and Christopher Stemple. "Development of a Remote Pulse Oximeter." Thesis, The University of Arizona, 2010. http://hdl.handle.net/10150/146648.
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Pulse oximetry is widely maintained as the standard method for measuring a person?s blood oxygen saturation. Monitoring such a vital sign allows for detecting the onset and progression of various diseases and conditions that could result in tissue and organ damage or death due to lack of required oxygen delivery. The goal of this project was to design a pulse oximeter geared toward consumer use that could wirelessly transmit data to a portable device, such as a smartphone, for convenient, remote monitoring of oxygen saturation. This report describes the design process for developing a working prototype of the pulse oximeter. Texas Instruments sponsored this project for the Interdisciplinary Engineering Design Program at the University of Arizona. Their goal in funding this project was to develop an intimate knowledge base of the considerations, components, and overall design of a pulse oximeter in order to better assist their customers. The creation of the pulse oximeter reference design was inspired by thorough research on the scientific principles underlying pulse oximetry as well as existing pulse oximeter technologies. From the information collected, the team developed three potential designs for the device. Analysis of each design was conducted to distinguish the one design that would be further developed and fabricated into the working reference design required by the project sponsor. Results obtained by testing the final prototype, discussion of future directions for the reference design, and conclusions drawn from the completion of the project are also presented in this report.
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Morey, Erica Katherine, Brian Bailey, Brian Ebel, Scott Galvin, Jack Grantham, Scott Little, Joseph Sankman, and Christopher Stemple. "Development of a Remote Pulse Oximeter." Thesis, The University of Arizona, 2010. http://hdl.handle.net/10150/156896.
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Pulse oximetry is widely maintained as the standard method for measuring a person's blodd oxygen saturation. Monitoring such a vital sign allows for detecting the onset and progression of various diseases and conditions that could result in tissue and organ damage or death due to lack of required oxygen delivery. The goal of this project was to design a pulse oximeter geared toward consumer use that could wirelessly transmit data to a portable device, such as a smartphone, for convenient, remote monitoring of oxygen saturation. This report describes the design process for developing a working prototype of the pulse oximeter. Texas Instruments sponsored this project for the Interdisciplinary Engineering Design Program at the University of Arizona. Their goal in funding this project was to develop an intimate knowledge base of the considerations, components, and overall design of a pulse oximeter in order to better assist their customers. The creation of the pulse oximeter reference design was inspired by thorough research on the scientific principles underlying pulse oximetry as well as existing pulse oximeter technologies. From the information collected, the team developed three potential designs for the device. Analysis of each design was conducted to distinguish the one design that would be further developed and fabricated into the working reference design required by the project sponsor. Results obtained by testing the final prototype, discussion of future directions for the reference design, and conclusions drawn from the completion of the project are also presented in this report.
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Kayani, Badar Jahangir. "DEVELOPMENT OF CONTINUOUS MONITORING PULSE OXIMETER DEVICE." Case Western Reserve University School of Graduate Studies / OhioLINK, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=case1619622233546762.
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Pujary, Chirag Jayakar. "Investigation of Photodetector Optimization in Reducing Power Consumption by a Noninvasive Pulse Oximeter Sensor." Digital WPI, 2004. https://digitalcommons.wpi.edu/etd-theses/108.
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Noninvasive pulse oximetry represents an area of potential interest to the army, because it could provide cost-effective, safe, fast and real-time physiological assessment in a combat injured soldier. Consequently, there is a need to develop a reliable, battery-powered, wearable pulse oximeter to acquire and process photoplethysmographic (PPG) signals using an optimized sensor configuration. A key requirement in the optimal design of a wearable wireless pulse oximeter is low power management without compromising signal quality. This research investigated the advantage gained by increasing the area of the photodetector and decreasing the light emitting diode (LED) driving currents to reduce the overall power requirement of a reflectance mode pulse oximeter sensor. In vitro and preliminary in vivo experiments were conducted to evaluate a multiple photodetector reflectance sensor setup to simulate a varying detection area. It was concluded that a reflection pulse oximeter sensor employing a large area photodetector is preferred over a similar transmission type sensor for extending the battery life of a wireless pulse oximeter intended for future telemedicine applications.
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Smith, Reuben Nathanael. "Perioperative comparison of the agreement between a portable fingertip pulse oximeter vs. a conventional bedside pulse oximeter in adult patients (COMFORT trial)." Master's thesis, University of Cape Town, 2018. http://hdl.handle.net/11427/29680.
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Background: Low-cost, portable fingertip pulse oximeters are widely available to health professionals and the public. They are often not tested to ISO standards, or only undergo accuracy studies in healthy volunteers under ideal laboratory conditions. This study aims to pragmatically evaluate the agreement between one such device and a conventional bedside pulse oximeter in a clinical setting, in patients with varied comorbidities and skin pigmentations. Methods: A single-centre equipment comparison study was conducted. Simultaneous measurements were obtained in 220 patients with both a Contec CMS50D Fingertip Pulse Oximeter and a Nihon Kohden Life Scope MU-631 RK conventional bedside monitor. Peripheral oxygen saturations (SpO₂) and pulse rates were documented, and patient skin tone was recorded using the Fitzpatrick scale. Data was assessed using a Bland-Altman analysis with bias, precision and limits of agreement (LOA) calculated with 95% confidence intervals. A priori acceptability for LOA was determined to be 3%, in keeping with international standards. Results: Mean difference (therefore bias) between the conventional and fingertip oximeters for all data was -0,55% (95% CI -0,73 to -0,36%). Upper and lower limits of agreement (95% CI) were 2,16 (1,84 to 2,47) and -3,25 (-3,56 to -2,94) %. Regression analysis demonstrated worsening agreement with decreasing SpO₂. When samples were separated into “normal” (SpO₂ ≥ 93%) and “hypoxaemic” (SpO₂ < 93%) groups, the normal range displayed acceptable agreement between the two oximeters (bias -0,20 with LOA 2,20 to -2,27%), while the hypoxaemic group fell outside the study’s a priori limits. Heart rate measurements had mean difference (LOA) of -0,43 (-5,61 to 4,76) beats per minute. The study was not powered to detect difference among the skin tones, but demonstrated no trend for this parameter to alter the SpO₂ measurements. Conclusions: During normoxia, portable fingertip pulse oximeters are reliable indicators of SpO₂ and pulse rates in patients with various comorbidities in a pragmatic clinical context. However, they display worsening agreement with conventional pulse oximeters during hypoxaemia. Skin tones do not appear to adversely affect measurements.
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Li, Kejia. "Wireless reflectance pulse oximeter design and photoplethysmographic signal processing." Thesis, Manhattan, Kan. : Kansas State University, 2010. http://hdl.handle.net/2097/4143.
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Shokouhian, Mohsen. "Power-efficient and high-performance interference resilient pulse oximeter." Thesis, University of Westminster, 2014. https://westminsterresearch.westminster.ac.uk/item/8yv9v/power-efficient-and-high-performance-interference-resilient-pulse-oximeter.
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This thesis presents a novel sigma delta-based pulse oximeter with higher resilience against ambient light interference in comparison to the conventional pulse oximeters available in the market. The pulse oximeter reported in this thesis uses a novel cross-coupled sigma delta modulator to drive the pulse oximeter LEDs with two chaotic, non-overlapping pulse density modulated sequences. The deployment of this modulator not only provides more immunity against ambient light but it also offers more control over the pulse oximeter LEDs power consumption resulting in less power consumption under low ambient light conditions. Additionally, this thesis suggests a novel trans-impedance amplifier (TIA) topology for better detection of the physiological signal under low perfusion state and weak heart pulses. The TIA increases the physiological signal power by partially removing its DC component and providing enough headroom for the amplification of the AC physiological signal. This AC physiological signal is used to calculate the level of blood oxygenation and its accurate detection has a direct impact on the accuracy of the overall pulse oximeter measurement. The thesis also offers a detailed description about the computer model of the pulse oximeter developed in Simulink. This model is the first computer model of pulse oximeter and it is a useful tool for design and development of a pulse oximeter. Comparing the hardware measurement results and the Simulink simulation results presented in Chapter 2 and 5 reflects the capability of the model in predicting the behavior of pulse oximeter under different measurement conditions. The thesis also includes a detailed explanation about our flexible PC-based pulse oximeter hardware prototype which was used as a reference to evaluate the performance of our novel sigma delta-based pulse oximeter. This PC-based conventional pulse oximeter prototype performs the entire signal processing tasks within the Matlab environment and therefore it can be individually used as a platform to design and evaluate the new signal processing algorithms designed for pulse oximeter application. Finally the thesis reports on the standalone FPGA based fixed point implementation of the novel pulse oximeter processing chain on a Xilinx Spartan 3 FPGA Fabric, with real-time measurement results compared and contrasted against the results obtained from the Matlab based processing engine.
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Avakh, Kisomi Alireza. "A novel wireless ring-shaped multi-site pulse oximeter." Master's thesis, Université Laval, 2017. http://hdl.handle.net/20.500.11794/27891.
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Ces dernières années, la supervision continue des signes vitaux des patients a été un sujet d'intérêt de plusieurs travaux de recherche surtout pour ceux qui souffrent de maladies chroniques ou qui travaillent dans des environnements hasardeux. Dans la pratique médicale moderne, le niveau d'oxygène dans le sang est un des signes vitaux primaires tels que la pression artérielle, la fréquence cardiaque, la température corporelle et le rythme respiratoire. L'oxymétrie de pouls est une technique populaire non-intrusive qui permet de diagnostiquer des problèmes liés aux systèmes respiratoire et circulatoire. Pour cette raison, elle est largement utilisée dans les soins intensifs, les salles d'opération, les soins d'urgence, la naissance et l'accouchement, les soins néonatals et pédiatriques, les études du sommeil et les soins vétérinaires. Or, pour l’oxymètre de pouls, une acquisition précise des signaux est importante pour assurer la fiabilité des mesures de la saturation d'oxygène artériel (SaO2). Dans ce cas, le positionnement des capteurs joue un rôle important car la complexité de la structure du tissu du doigt peut rendre l'effet de l'emplacement de la source lumineuse imprévisible sur la mesure du SpO2. Si tel est le cas, un faible nombre de capteurs autour du doigt pourrait perturber la trajectoire des rayons de lumière et corrompre les mesures. Les oxymètres de pouls conventionnels utilisent une pince à doigts contenant les capteurs qui utilise un seul ensemble de LED et photodétecteur (PD). En plus de l'inconvénient des pinces à doigts, le placement du capteur n'est pas corrigé et sera affecté par des artefacts de mouvement. Dans ce mémoire, nous présenterons un oxymètre qui utilise six ensembles de diodes électroluminescentes et de photo-détecteurs, répartis uniformément en anneau autour du doigt, ce qui permet d'identifier le meilleur chemin de signal, immunisant ainsi l'acquisition du signal à l'effet de position de l'anneau. En outre, pour éliminer les fils de la station de base, ce système utilise un émetteur-récepteur radio ce qui supprime les inconvénients de l'attachement. Dans cette étude de conception de preuve de concept, un prototype de cet oxymètre en anneau est réalisé avec des composants commerciaux à faible consommation de courant et le tout est montés sur une carte électronique flex-rigides qui communique avec un hôte distant par un lien sans-fil pour traiter le signal et calculer le niveau d'oxygène.Continuous health monitoring for patients with chronic diseases or people working in high-risk environments has been an interesting topic of research in recent years. In modern medical practice, the blood oxygen level is one of the vital signs of the body alongside blood pressure, heart rate, body temperature, and breathing rate. Pulse oximeters provide early information on problems in the respiratory and circulatory systems. They are widely used in intensive care, operating rooms, emergency care, birth and delivery, neonatal and pediatric care, sleep studies, and in veterinary care. Proper signal acquisition in a pulse oximetry system is essential to monitor the arterial oxygen saturation (SaO2). Since the tissue of finger has a complicated structure, and there is a lack of detailed information on the effect of the light source and detector placement on measuring SpO2, sensor placement plays an important role in this respect. Not enough sensors placed around the finger will have an adverse effect on the light path so high signal quality may become impossible to achieve. The conventional Pulse Oximeters use a finger clip, which uses only one set of LEDs and photodetector (PD). In addition to the inconvenience of the finger clips, the placement of the sensor is not fixed and will be affected by motion artifacts. In this thesis, we present a ring-shaped oximeter that uses six sets of light emitting diodes and photodetectors, uniformly distributed around the finger to identify the best signal path, thus making the signal acquisition immune to ring position on the finger. In addition, this system uses a radio transceiver to eliminate the connection wires to a base station which removes the inconvenience of the tethering and reduce the motion artifacts. In this proof of concept study, this novel ring oximeter is implemented with commercial low power consumption off-the-shelf components mounted on a rigid-flex board that connects to a remote host for signal processing and oxygen level calculation.
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Parsons, Jennifer Kathleen Hendryx. "ROx3: Retinal Oximetry Utilizing the Blue-Green Oximetry Method." Diss., The University of Arizona, 2014. http://hdl.handle.net/10150/338698.
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The ROx is a retinal oximeter under development with the purpose of non-invasively and accurately measuring oxygen saturation (SO₂) in vivo. It is novel in that it utilizes the blue-green oximetry technique with on-axis illumination. ROx calibration tests were performed by inducing hypoxia in live anesthetized swine and comparing ROx measurements to SO₂ values measured by a CO-Oximeter. Calibration was not achieved to the precision required for clinical use, but limiting factors were identified and improved. The ROx was used in a set of sepsis experiments on live pigs with the intention of tracking retinal SO₂ during the development of sepsis. Though conclusions are qualitative due to insufficient calibration of the device, retinal venous SO₂ is shown to trend generally with central venous SO₂ as sepsis develops. The novel sepsis model developed in these experiments is also described. The method of cecal ligation and perforation with additional soiling of the abdomen consistently produced controllable severe sepsis/septic shock in a matter of hours. In addition, the ROx was used to collect retinal images from a healthy human volunteer. These experiments served as a bench test for several of the additions/modifications made to the ROx. This set of experiments specifically served to illuminate problems with various light paths and image acquisition. The analysis procedure for the ROx is under development, particularly automating the process for consistency, accuracy, and time efficiency. The current stage of automation is explained, including data acquisition processes and the automated vessel fit routine. Suggestions for the next generation of device minimization are also described.
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Meghjani, Zahra. "Low-cost, Wireless Optical Oximeter for Monitoring of Brain Function in High-risk Pediatric Population." Wright State University / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=wright1484672584193275.
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Zahari, Marina. "Analysis of oxygenation and other risk factors of retinopathy of prematurity in preterm babies." Thesis, University of Canterbury. School of Mathematics and Statistics, 2015. http://hdl.handle.net/10092/10911.
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Maintaining adequate and stable blood oxygen level is important for preterm babies to avoid the risk of brain, lung and retinal injury such as retinopathy of prematurity (ROP). However, wide disparities in policies and practices of oxygenation in preterm babies exist among neonatal care providers as it is still unclear which best method of monitoring and what features of oxygen measurements are important to clinician’s interpretations for assessing preterm babies at risk of developing severe ROP or unstable health condition. This thesis consists of two projects: NZ-ROP that examines multiple factors of severe ROP including summary statistics (mean, standard deviation (SD), coefficient of variation (CV) and desaturation) for oxygen saturation (OS) features in very extreme preterm babies, and NZ-LP that investigates the efficacy of some of these statistics for health monitoring of late preterm babies.
The OS data in NZ-ROP were recorded using modified oximeters that have offsets and inherent software artefact, both of which mask the actual saturation for certain OS ranges and may complicate the choice of methods in the analyses. Therefore, novel algorithms involving linear and quadratic interpolations are developed, implemented on the New Zealand data, and validated using the data of a UK preterm baby, as recorded from offsets and non-offsets oximeters. For all data sets, the algorithms produced saturation distributions that were very close to those obtained from the non-offset oximeter. The algorithms perform within the recommended standards of commercial oximeters currently used in the clinical practice.
ROP is a multifactorial disease, with oxygenation fluctuations as one of the key contributors. The all-subsets logistic regression, robust and generalised additive statistical modelling, along with a model averaging approach, are applied in NZ-ROP to determine the relationship of variability and level of OS with severe ROP, and the extent of contribution of various clinical predictors to the severity of this eye disease. Desaturation, as a measure of OS variability, has the strongest association with severe ROP among all OS statistics, in particular, the risk of severe ROP is almost three times higher in babies that exhibit greater occurrences of desaturation episodes. Additionally, this study identifies longer periods of ventilation support, frequent desaturation events, extreme prematurity and low birth weight as the most important factors that substantially exacerbate the severity of ROP, and therefore signify babies’ underlying condition of being severely ill.
Persistent cardiorespiratory instabilities prior to hospital discharge may expose preterm babies to a greater risk of neuro-developmental impairments. In NZ-LP, the statistical summaries of mean, SD and CV are computed from the OS measurements of healthy stable and unstable babies, and the performance of these statistics in detecting the unstable babies is evaluated using an extremeness index for outlying data and a hierarchical clustering technique. With SD and CV, the clinically unstable babies were very well separated from the group of stable babies, wherein, the separation was even more apparent with the use of CV. These suggest that measures of variability could be better than saturation level for highlighting babies’ underlying instability due to immature physiological systems, but the combination of variability and level through the CV are believed to be even better.
Identification and summarisation of useful OS features quantitatively hold great promise for improved monitoring of oxygenation instability and diagnosis of severe ROP for preterm babies.
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Von, chong echevers Alejandro. "Nouvelle approche pour l'estimation de la saturation en oxygène du sang artériel en utilisant un capteur multispectrale." Thesis, Cergy-Pontoise, 2019. http://www.theses.fr/2019CERG1023.
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Ce manuscrit présente les travaux réalisés pour la mise au point d’un système d’estimation du taux d’oxygénation connu aussi sous le nom d’oxymètre de pouls. Ledit outil est indispensable, notamment dans le domaine médical, pour la surveillance des patients lors des interventions anesthésiques, pour les soins post-opératoires et aux urgences puisqu’il fournit de l’information relative à l’efficacité respiratoire et au rythme cardiaque. Le principe d’opération de ce dernier est basé sur la différence en absorption optique entre le sang oxygéné et le sang désoxygéné à l’aide d’une photodiode simple comme moyen de détection. Dans ce travail de recherche, nous introduisons une nouvelle méthode basée sur la différence des spectres d’absorption entre le sang oxygéné et le sang désoxygéné en utilisant un photodétecteur multispectrale.En premier lieu, une introduction et une analyse de l’état de l’art sont faites afin de mieux comprendre la théorie derrière l’oxymétrie de pouls et de mettre en évidence les limitations des méthodes actuelles, ce qui nous permettra de positionner scientifiquement et techniquement les contributions. Ensuite, une explication détaillée du système conçu, concernant l’électronique, l’acquisition et traitement des signaux est décrite.Finalement, nous présentons les résultats obtenus avec la méthode proposée. D’abord, une preuve de concept à plusieurs longueurs d’onde a été faite avec un spectromètre comme moyen de détection afin de valider le principe de fonctionnement de notre méthode. Pour ce faire, nous avons effectué des tests de désoxygénation par rétention de la respiration conjointement avec un oxymètre de haute gamme comme moyen de comparaison. Une fois le principe validé, nous avons remplacé le spectromètre par un capteur multispectrale. Nous avons alors montré que les estimations faites avec notre méthode, en régime stable, tombaient dans la tolérance permise par la norme ISO régulant les oxymètres de pouls.Ces travaux ouvrent une voie alternative et complémentaire à l’étude de l’oxymétrie de pouls capable de surmonter plusieurs limitations présentes dans la technique conventionnelle, en particulier dans le cadre du design d’implants autonomes. Des essais cliniques à venir permettront d’approfondir sur l’utilité de cette méthode et ses limitationsThis manuscript presents the work done to develop an alternative system for the estimation of the oxygen saturation of blood, also known as pulse oximeter. It is an essential tool, especially in the medical field, for patient monitoring during anesthesia procedures, post-operative care and emergencies, since it provides information related to the respiratory efficiency and heart rate. The principle of operation of the latter is based in the difference in optical absorption between oxygenated blood and deoxygenated blood using a simple photodiode as the sensor. In this research work, we introduce a new method based on the difference between the absorption spectrum between oxygenated blood and deoxygenated blood using a multispectral photodetector.In the first place, an introduction and analysis of the state of the art are made to better understand the theory behind pulse oximetry and highlight the limitations of current methods, which will allow us to position ourselves scientifically and technologically, for our contribution. Then, a detailed explanation of the designed system, concerning the electronics, the acquisition and signal processing is described.Finally, we present the results obtained with our proposed method. First, a proof of concept at several wavelengths was made with a spectrometer as a means of detection to validate the principle of operation. To accomplish deoxygenation, breath holding tests were carried out in conjunction with a high-end oximeter as a means of comparison. Once the principle was validated, we replaced the spectrometer with a multispectral sensor. We found that the estimates made with our method, under stable state conditions, fell within the tolerance allowed by the ISO standard regulating pulse oximeters.Since this is a new principle, we consider that with this work, we open an additional path to the study of pulse oximetry which might allow to overcome several limitations present in the conventional technique. Future clinical trials will explore the usefulness of this method and its limitations
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Ndikintum, Nfii Kangong. "A Special Inference Problem in Repeated Measures Design with Applications to Pulse Oximetry." University of Cincinnati / OhioLINK, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1177418766.
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Lin, Tianyu. "Wireless Biomedical Sensor Network Reference Design Based on the Intel® Edison Platform." Thesis, Kansas State University, 2017. http://hdl.handle.net/2097/36193.
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Master of ScienceDepartment of Electrical and Computer Engineering
Steven Warren
A reference design for a wearable, wireless biomedical sensor set has been a long-term need for researchers at Kansas State University, driven by the idea that a basic set of sensor components could address the demands of multiple types of human and animal health monitoring scenarios if these components offered even basic reconfigurability. Such a reference design would also be a starting point to assess sensor performance and signal quality in the context of various biomedical research applications. This thesis describes the development of a set of wireless health monitoring sensors that can be used collectively as a data acquisition platform to provide biomedical research data and to serve as a baseline reference design for new sensor and system development. The host computer, an Intel Edison unit, offers plug-and-play usability and supports both Wi-Fi and Bluetooth wireless connectivity. The reference sensor set that accompanies the Intel Edison single-board computer includes an electrocardiograph, a pulse oximeter, and an accelerometer/gyrometer. All sensors are based on the same physical footprint and connector placement so that the sensors can be stacked to create a collection with a minimal volume and footprint. The latest hardware version is 3.1. Version 1.0 supported only a pulse oximeter, whereas version 2.0 included an electrocardiograph, pulse oximeter, and respiration belt. In version 3.0, the respiration belt was removed, and accelerometers and gyroscopes were added to the sensor set. Version 3.1 is a refined version of the latter design, where known hardware bugs were remedied. Future work includes the development of new sensors and casing designs that can hold these sensor stacks.
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Marwah, Kunal. "Development of Motion Artifact Rejection Algorithms for Ambulatory Heart Rate and Arterial Oxygen Measurement By A Wearable Pulse Oximeter." Digital WPI, 2012. https://digitalcommons.wpi.edu/etd-theses/1320.
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Over the past decade, there has been an increasing interest in the real-time monitoring of ambulatory vital signs such as heart rate (HR) and arterial blood oxygen saturation (SpO2) using wearable medical sensors during field operations. These measurements can convey valuable information regarding the state of health and allow first responders and front-line medics to better monitor and prioritize medical intervention of military combatants, firefighters, miners and mountaineers in case of medical emergencies. However, the primary challenge encountered when using these sensors in a non-clinical environment has been the presence of persistent motion artifacts (MA) embedded in the acquired physiological signal. These artifacts are caused by the random displacement of the sensor from the skin and lead to erroneous output readings. Several signal processing techniques, such as time and frequency domain segmentation, signal reconstruction techniques and adaptive noise cancellation (ANC), have been previously developed in an offline environment to address MA in photoplethysmography (PPG) with varying degrees of success. However, the performance of these algorithms in a spasmodic noise environment usually associated with basic day to day ambulatory activities has still not been fully investigated. Therefore, the focus of this research has been to develop novel MA algorithms to combat the effects of these artifacts. The specific aim of this thesis was to design two novel motion artifact (MA) algorithms using a combination of higher order statistical tools namely Kurtosis (K) for classifying 10 s PPG data segments, as either ‘clean’ or ‘corrupt’ and then extracting the aforementioned vital parameters. To overcome the effects of MA, the first algorithm (termed ‘MNA’) processes these ‘corrupt’ PPG data segments by identifying abnormal amplitudes changes. The second algorithm (termed ‘MNAC’), filters these ‘corrupt’ data segments using a 16th order normalized least mean square (NLMS) ANC filter and then extracts HR and SpO2.
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Serpa, Giulliano Caixeta. "Oximetria de pulso na determinação da saturação de oxigênio de pré-molares em diferentes faixas etárias." Universidade Federal de Goiás, 2015. http://repositorio.bc.ufg.br/tede/handle/tede/7268.
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Objective: The aim of this study was to establish the level of oxygen saturation in normal pulps of premolars maxilary in different age groups. Methodology: 120 premolars were selected in normal conditions and pulp divided by age of 24 teeth each: 20-24 years; 25-29 years; 30-34 years; 35-39 years; 40 to 44 years. the level of oxygen saturation of these teeth was determined by pulse oximetry. The ANOVA was used to check for differences between these age groups in the level of oxygen saturation and the Tukey test to identify which differed from each other. Results: The mean oxygen saturation encompassing all age groups was 86,2%, already for each separately it was found that: 20-24 years (89,71%), 25-29 years (87,67%) 30 to 34 years (88,71%), 35-39 years (84,80%), 40-44 years (80,00%), with the latter being statistically significant reduced level of others. Conclusion: The oxygen saturation level in normal pulps premolars averaged 86.2%, a significant reduction from 40 to 44 years.
Objetivo: Estabelecer o nível de saturação de oxigênio em polpas normais de pré-molares em diferentes faixas etárias. Material e Método: Foram selecionados 120 pré-molares superiores humanos em condições pulpares de normalidade e divididos por faixa etária (n=24): 20 a 24 anos; 25 a 29 anos; 30 a 34 anos; 35 a 39 anos; 40 a 44 anos. O nível de saturação dos dentes foram avaliados por um oximetro de pulso. A análise de variância ANOVA foi utilizada para verificar a existência de diferença entre as faixas etárias em relação ao nível de saturação de oxigênio, e o teste de Tukey para identificar quais diferiam entre si. Resultados: A média de saturação de oxigênio em todas as faixas etárias foi de 86,2%. A análise dos valores obtidos em cada faixa sugere que na última faixa etária verificou-se um nível reduzido, significante em relação as demais [(20 a 24 anos (89,71%); 25 a 29 anos (87,67%); 30 a 34 anos (88,71%); 35 a 39 anos (84,80%); 40 a 44 anos (80,00%)]. Conclusão: O nível de saturação de oxigênio em polpas normais de pré-molares apresentou uma média de 86,2%, com redução significante entre 40 a 44 anos.
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KATSUMATA, YOSHINAO, MASAYOSHI TERASHIMA, TATSURO OHTA, TAMOTSU OKADA, and KAZUO KATSUMATA. "Incidence of Sleep Apnea Syndromes in General Patients at a Hospital for Internal Medicine." Nagoya University School of Medicine, 1986. http://hdl.handle.net/2237/17491.
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Comtois, Gary W. "Implementation of Accelerometer-Based Adaptive Noise Cancellation in a Wireless Wearable Pulse Oximeter Platform for Remote Physiological Monitoring and Triage." Digital WPI, 2007. https://digitalcommons.wpi.edu/etd-theses/1005.
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"A wireless wearable battery-operated pulse oximeter has been developed in our laboratory for field triage applications. The wearable pulse oximeter, which uses a forehead-mounted sensor to provide arterial oxygen saturation (SpO2) and heart rate (HR) information, would enable field medics to monitor vital physiological information following critical injuries, thereby helping to prioritize life saving medical interventions. This study was undertaken to investigate if accelerometry (ACC)-based adaptive noise cancellation (ANC) is effective in minimizing SpO2 and HR errors induced during jogging to simulate certain motion artifacts expected to occur in the field. Preliminary tests confirmed that processing the motion corrupted photoplethysmographic (PPG) signals by simple Least-Mean-Square (LMS) and Recursive Least-Squares (RLS) ANC algorithms can help to improve the signal-to-noise ratio of motion-corrupted PPG signals, thereby reducing SpO2 and HR errors during jogging. The study showed also that the degree of improvement depends on filter order. In addition, we found that it would be more feasible to implement an LMS adaptive filter within an embedded microcontroller environment since the LMS algorithm requires significantly less operations."
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Ramuka, Piyush R. "Real-Time Adaptive Noise Cancellation in Pulse Oximetry: Accuracy, Processing Speed and Program Memory Considerations." Digital WPI, 2009. https://digitalcommons.wpi.edu/etd-theses/116.
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A wireless, battery operated pulse oximeter system with a forehead mounted optical sensor was designed in our laboratory. This wireless pulse oximeter (WPO) would enable field medics to monitor arterial oxygen saturation (SpO2) and heart rate (HR) information accurately following injuries, thereby help to prioritize life saving medical interventions when resources are limited. Pulse oximeters developed for field-based applications must be resistant to motion artifacts since motion artifacts degrade the signal quality of the photoplethysmographic (PPG) signals from which measurements are derived. This study was undertaken to investigate if accelerometer-based adaptive noise cancellation (ANC) can be used to reduce SpO2 and HR errors induced by motion artifacts typically encountered during field applications. Preliminary studies conducted offline showed that ANC can minimize SpO2 and HR errors during jogging, running, and staircase climbing. An 8th order LMS filter with ì = 0.01 was successfully implemented in the WPO's embedded microcontroller. After real-time adaptive filtering of motion corrupted PPG signals, errors for HR values ranging between 60 - 180BPM were reduced from 12BPM to 6BPM. Similarly, ambient breathing SpO2 errors were reduced from 5% to 2%.
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Islam, Asif Moinul. "Case Based Reasoning method for analysis of Physiological sensor data." Thesis, Örebro universitet, Institutionen för naturvetenskap och teknik, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:oru:diva-27672.
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Remote healthcare is a demanding as well as emergent research area. The rise of healthcare costs in the developed countries have made the policy makers for trying to find an alternate model of healthcare rather than relying on traditional healthcare system. Although advancement in the sensor technology, forthcomingness of devices like smart phones and improvement in artificial intelligence technology have made the remote healthcare close to reality but still there are plenty of issues to be solved before it becomes a commonly used healthcare model. In this thesis, studies of two vital physiological parameters pulse rate and oxygen saturation were done to unearth some patterns using Case-Based Reasoning technique. A three-tiered application is developed focusing remote healthcare. The results of the thesis could be used as a starting point of further research of two above mentioned physiological parameters in order to detect anomalous condition of health.
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Islam, Asif Moinul. "Case Based Reasoning method for analysing Physiological sensor data." Thesis, Örebro universitet, Institutionen för naturvetenskap och teknik, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:oru:diva-27725.
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Remote healthcare is a demanding as well as emergent research area. The rise of healthcare costs in the developed countries have made the policy makers for trying to find an alternate model of healthcare rather than relying on traditional healthcare system. Although advancement in the sensor technology, forthcomingness of devices like smart phones and improvement in artificial intelligence technology have made the remote healthcare close to reality but still there are plenty of issues to be solved before it becomes a commonly used healthcare model. In this thesis, studies of two vital physiological parameters pulse rate and oxygen saturation were done to unearth some patterns using Case-Based Reasoning technique. A three-tiered application is developed focusing remote healthcare. The results of the thesis could be used as a starting point of further research of two above mentioned physiological parameters in order to detect anomalous condition of health.
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Šmíd, Josef. "Měření nasycení krve kyslíkem." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2012. http://www.nusl.cz/ntk/nusl-219747.
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This thesis works with measuring possibilities of blood oxygen saturation, analysis methods used and their calibration. It also deals with design of the block diagram of pulse oximeter for measuring blood oxygen saturation.
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Andersson, Klara, and Paulsson Esther Busch. "Accuracy Validation of Pulse Oximeters used at Hospitals : A Cross-Sectional Study performed in Stockholm." Thesis, KTH, Skolan för teknik och hälsa (STH), 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-210030.
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This thesis had the purpose to look into the accuracy of the pulse oximeter, the experienced as well as the actual. A pulse oximeter utilizes optics to non-invasively estimate the oxygen saturation (SO2) in the blood with an indirect value (SpO2). The accuracy of the pulse oximeter and its two belonging sensors (ear and finger) was compared against the method that is considered to give the most reliable value of this parameter, i.e. arterial blood gas test (SaO2). The experienced accuracy was evaluated with the help of a questionnaire. The target group was healthcare professionals at four main hospitals in Stockholm, and further three departments were chosen at each hospital; lung, cardiology, and emergency department. Additional data was collected with help of measurements performed on patients, where readings from pulse oximeters were compared against arterial blood gas tests. Data was collected from two measurement sites on the body, the ear and the finger. Differences between SpO2 and SaO2 as well as differences between ear and finger for the same pulse oximeter were investigated. The result from the two methods indicated that the healthcare professionals were aware of existing deviations between SpO2 and SaO2, and some also had strategies to deal with them. The trend of the collected data was analyzed to draw a conclusion of the most accurate pulse oximeter according to the tests. There was not enough data collected to make any statistical conclusion, but according to the data none of the pulse oximeters fulfilled the set requirement. Differences existed when SpO2 was compared against SaO2, and also when SpO2 from the ear and finger for the same pulse oximeter were compared against each other. According to the data, one pulse oximeter was concluded to be more accurate than the others. Suggestions for future work can be to collect a bigger amount of data to be able to draw a statistical conclusion, and eventually focus on interviews to look deeper into the healthcare professionals’ strategies and workflow.Den här uppsatsen syftade till att undersöka pulsoximeterns mätnoggrannhet, så väl den upplevda som den faktiska. En pulsoximeter utnyttjar optik för att icke-invasivt uppskatta syremättnaden (SO2) i blodet med ett indirekt värde (SpO2). Mätnoggrannheten hos pulsoximetern och dess två sensorer (öra och finger) jämfördes med den metod som anses ge det mest korrekta värdet av denna parameter, dvs. analys av arteriellt blodgastest (SaO2). Den upplevda mätnoggrannheten studerades med hjälp av enkät. Målgruppen var sjukvårdspersonal anställda på fyra stora sjukhus i Stockholm, och vidare valdes tre avdelningar; lungvårds-, hjärtintensivvårds- och akutvårdsavdelningen. Vidare samlades data in genom utförda mätningar på patienter, värden erhållna med hjälp av pulsoximetrar jämfördes med blodgastester. Data samlades in från två mätställen, öra och finger, för respektive pulsoximeter. Skillnader mellan SpO2 och SaO2 samt skillnader mellan öra och finger för samma pulsoximeter undersöktes. Resultatet av de två metoderna visade att sjukvårdspersonalen är väl medvetna om att skillnader existerar mellan SpO2 och SaO2, och även att många hade strategier för att hantera dessa. Trenden hos data som samlades in med hjälp av testerna utnyttjades för att kunna dra en slutsats angående mätnoggrannheten i relation till blodgastester. För lite data samlades in för att kunna dra någon statistisk slutsats, men data pekade på att ingen av de testade pulsoximetrarna uppfyllde den av författarna fastställda accepterade skillnaden. Skillnader visade sig existera vid jämförelse mellan SpO2 och SaO2, och även när SpO2 från örat och finger för samma pulsoximeter jämfördes mot varandra. Enligt data var en av de testade pulsoximeterna mer noggrann än de andra. Förslag på framtida arbete kan vara att samla in mer data för att ta fram ett statistiskt resultat, samt eventuellt komplettera datainsamlingen med intervjuer för att vidare undersöka strategier och arbetssätt hos sjukvårdspersonalen.
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Samuel, Theresa. "The utility of occlusion of the pulse oximeter trace in the estimation of systolic blood pressure during spinal anaesthesia for caesarean section: the effect of body mass index." Master's thesis, University of Cape Town, 2016. http://hdl.handle.net/11427/23653.
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Background: We compared the accuracy and precision of estimation of the systolic blood pressure (SBP) by disappearance of the pulse oximeter trace (DOT), with noninvasive blood pressure (NIBP) measurement, across the range of body mass index (BMI), during spinal anaesthesia (SA) for caesarean section (CS). Methods: Three groups of 25 parturients were recruited, with BMI of < 30- (Group 1), 30-40- (Group 2), and > 40 kg/m2 (Group 3) respectively. SBP was measured using the DASH® 3000 monitor (GE Health Care, UK) NIBP monitor, placed on the same arm as the pulse oximeter probe. Estimations of SBP were done before- and 5 minutes after induction of SA, during cuff inflation and deflation. The times taken for the estimations and the actual NIBP measurements were noted. Bland and Altman analysis was performed and the correlation coefficient estimated. Results: Concerning the most clinically relevant estimation, namely SBP during inflation post-SA: For Groups 1, 2 and 3, r = 0.56, 0.74 and 0.91; bias = -0.4, -2.9 and 0.8 mmHg, and limits of agreement = -27.7 to 26.9, -27.7 to 21.9 and -15.9 to 17.5 mmHg respectively. The mean (SD) time required for estimation of the SBP during inflation post- SA was 7.5 (1.1) s, 11.8 (3.8) s and 16.8 (4.2) s in the Groups 1, 2 and 3 respectively. The mean (SD) time required for measurement of post-SA SBP during inflations in Groups 1, 2 and 3, was 30.3 (13.1) s, 41.3 (10.2) s and 49.8 (14.6) respectively. In the post-SA period, mean time saved by estimating SBP during inflation was approximately 28.5 seconds, compared with 9 seconds during deflation. The time saved in Groups 1, 2 and 3 was 22.8 (13.2) s, 30.0 (11.6) s and 33.0 (15.6) s respectively. In the BMI > 40 kg/m2 group, the percentage error is ±13% of the mean systolic blood pressure observed, and the absolute error is ±16 mmHg, compared to ±27 mmHg in the normal BMI group. Conclusion: Post-SA estimation of SBP during cuff inflation in morbidly obese patients is more accurate and precise than in the other BMI Groups. Time to estimation is shorter than measurement by a clinically relevant period (33 s). This should improve patient safety in morbidly obese parturients.
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Vilhegas, Leonardo Zane. "Desenvolvimento de um protótipo para monitoração de saturação de oxigênio e freqüência cardíaca para roedores." Universidade de São Paulo, 2007. http://www.teses.usp.br/teses/disponiveis/3/3140/tde-20072009-180319/.
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A utilização de equipamentos para monitoração de parâmetros fisiológicos não é apenas crucial em pacientes que são submetidos a alguns procedimentos médicos, mas é também de extremo valor para animais em uso similar. Este projeto tem como principal objetivo o desenvolvimento de um sistema de monitoração de saturação de oxigênio e freqüência cardíaca para roedores; tal sistema é composto por um dispositivo protótipo compacto e sensor óptico. No presente trabalho, foram utilizadas as tecnologias dos microcontroladores da Microchip para realizar as diversas digitalizações; a tecnologia USB, para realizar a comunicação com computadores e o desenvolvimento da interface desenvolvida com o software disponível da National Instruments, o LabVIEW. Neste estudo, o sistema desenvolvido foi empregado em camundongos e foram realizadas diversas avaliações em laboratório e em campo para a validação do dispositivo protótipo. Os batimentos cardíacos e a saturação de oxigênio, tanto em repouso quanto em movimento, foram detectados pelo protótipo. Os valores de freqüência cardíaca variaram entre 545 e 700 bpm enquanto os valores de saturação de oxigênio variaram entre 80 a 95%.The equipments use to monitoring physiological parameters isnt just crucial in patients who are submitted to some medical procedures but it is also of extreme value for animals in similar use. This project has as main objective the development of a monitor oxygen saturation and cardiac frequency for mice; the system is compound of a compact prototype device and optic sensor. In the present work, the Microchip microcontrollers technologies had been used, to realize many digitalization; the USB technology interface, to realize the communication with computers and the interface development developed with the available National Instruments software, the LabVIEW. In this study, the developed system was used in mice and have been realized many evaluations in laboratory and field for the prototype validation device. The cardiac beatings and oxygen saturation, as much in rest how in movement they had been detected by the prototype. The values of heart rate had varied of 545 to 700 while the values of oxygen saturation had varied of 80 to 95%.
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Oliveira, Keila Surama Alves de. "Avaliação da saturação de oxigênio em polpas humanas de molares hígidos." Universidade Federal de Goiás, 2016. http://repositorio.bc.ufg.br/tede/handle/tede/8689.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES
Objective: to determine the oxygen saturation level (SaO2) in human pulps of molars by pulse oximetry. Methods: the oxygen saturation level was evaluated in 112 healthy molars using the pulse oximeter and the patient's response time to stimulus with the cold refrigerant gas Endo Ice and recorded with digital timer. Statistical analysis was performed using SPSS v program. 18.0. Quantitative variables were described by mean and standard deviation when the distribution was symmetric and median and interquartile range when asymmetric. Variables with symmetric distribution were compared between teeth for independent samples and intra-individual for paired samples by Student t test, and the asymmetric distribution with the Mann-Whitney test. To correlate the variables each other was used the Pearson correlation coefficient, and to compare more than two groups together the analysis of variance (ANOVA) followed by post-hoc Tukey, being statistically significant p <0,05. Results: the average level of SaO2 for the 112 pulps of healthy molars was 85,09%, and there was no correlation with the SaO2 average of the patient´s indicator finger (92,89%). There was a significant difference (P = 0,037) between the average level of SaO2 of the first (85,76%) and second superior molars (81,87%), and it was not significant (P = 0,177) between the first (85,58%) and second (88,15%) inferior molars. The superior molars had lower average level of SaO2 (83,59%) when compared to the inferior molars (86,89%), with a statistically significant difference (P = 0,018). The average of the patient's response time to the cold stimulus was 1,12 seconds, with no statistically significant difference between superior (1,25 seconds) and inferior molars (0,99 seconds). Conclusion: the average level of SaO2 in healthy molars pulps was 85,09%, and the average of the superior molars was 83,59% and inferior molars was 86,89%. The average of the patient's response time to the cold stimulus was 1,12 seconds, with no statistically significant difference between superior (1,25 seconds) and inferior molars (0,99 seconds) and there was no correlation between the patient's response time to the cold stimulus and the oxygen saturation level for healthy molars.
Objetivo: determinar o nível de saturação de oxigênio (SaO2) em polpas humanas de molares hígidos por meio da oximetria de pulso. Material e métodos: o nível de SaO2 foi avaliado em 112 molares hígidos utilizando-se o oxímetro de pulso, e o tempo de resposta do paciente ao estímulo ao frio com gás refrigerante e registrado com cronômetro digital. A análise estatística foi feita pelo programa SPSS v. 18.0. Foram descritas as variáveis quantitativas pela média e desvio padrão quando a sua distribuição foi simétrica e mediana e intervalo interquartil quando assimétrica. As variáveis com distribuição simétrica foram comparadas entre dentes para amostras independentes e intra-indivíduo para amostras pareadas pelo teste t de Student, e as com distribuição assimétrica pelo teste de Mann-Whitney. Para correlacionar as variáveis entre si foi utilizado o coeficiente de correlação de Pearson, e para comparar mais de dois grupos entre si o teste de Análise de Variância (ANOVA) seguido do teste post-hoc de Tukey, sendo estatisticamente significativo p < 0,05. Resultados: o nível médio de SaO2 para as 112 polpas dos molares hígidos foi 85,09%, e não houve correlação com a média do dedo indicador do paciente (92,89%). Houve uma diferença significante (P= 0,037) entre o nível médio de SaO2 dos primeiros (85,76%) e dos segundos molares superiores (81,87%), não sendo significante (P= 0,177) entre os primeiros (85,58%) e segundos (88,15%) molares inferiores. Os molares superiores apresentaram menor nível médio de SaO2 (83,59%) quando comparados aos inferiores (86,89%), sendo a diferença estatisticamente significativa (P= 0,018). A mediana do tempo de resposta do paciente ao estímulo ao frio foi de 1,12 segundos, não havendo diferença estatisticamente significativa entre molares superiores (1,25 segundos) e inferiores (0,99 segundos). Conclusão: o nível médio de SaO2 em polpas de molares hígidos foi de 85,09%, sendo a média dos molares superiores de 83,59% e a dos inferiores de 86,89%. A mediana do tempo de resposta do paciente ao estímulo ao frio em molares hígidos foi de 1,12 segundos, não havendo diferença estatística entre superiores (1,25 s) e inferiores (0,99), e não houve correlação entre o tempo de resposta do paciente ao estímulo ao frio e o nível de saturação de oxigênio para molares hígidos. Palavras-chave: oxímetro de pulso, polpa dentária, saturação de oxigênio, teste frio.
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Dresher, Russell Paul. "Wearable Forehead Pulse Oximetry: Minimization of Motion and Pressure Artifacts." Link to electronic thesis, 2006. http://www.wpi.edu/Pubs/ETD/Available/etd-050306-104212/.
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Thesis (M.S.)--Worcester Polytechnic Institute.Keywords: sensor attachment, wearable sensor, pulse oximetry, motion artifact, contact pressure, remote physiological monitoring. Includes bibliographical references (p.54-57).
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Schoevers, Jacobus Engelbertus. "Low blood oxygen saturation quantification in human arterial and venous circulation." Thesis, Stellenbosch : Stellenbosch University, 2008. http://hdl.handle.net/10019.1/21460.
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Thesis (MScIng)--Stellenbosch University, 2008.ENGLISH ABSTRACT: Conventional pulse oximetry has limited accuracy in measuring blood oxygen saturation in low saturation and perfusion scenarios. This limits the application of pulse oximetry in patients su ering from peripheral vascular a ictions. A novel pulse oximetry system is presented in this study which proposes solutions to these low saturation and perfusion issues. The presented system was designed to overcome the low perfusion issues by inducing an arti cial pulse in the detected photoplethysmograph. A novel arterio-venous hypothesis was formulated to extract arterial and venous saturation data from this arti cial photoplethysmograph using arterial-to-venous compliance ratios. Sensor wavelengths were selected to provide high and low saturation accuracy, followed by an in vitro sensor calibration procedure. System performance was validated by means of in vivo human studies. In vivo results indicate good accuracy for high saturation, with limited accuracy in low saturation scenarios. The arterio-venous hypothesis was validated, indicating that venous saturation information can be extracted from the arti cial PPG. Although inconclusive, results indicate that the proposed system might be able to accurately monitor arterial and venous saturation in severe hypoperfusion scenarios with recommended hardware and calibration modi cations. It is recommended that further studies into the presented system's performance are conducted.
AFRIKAANSE OPSOMMING: Konvensionele 'pulse oximetry' sisteme het beperkte akkuraatheid tydens die meting van bloed suurstof saturasie in lae saturasie en perfusie gevalle. Dit beperk die bruikbaarheid van 'pulse oximetry' in pasiënte wat ly aan perifere vaskulêre siektes. 'n Nuwe 'pulse oximetry' sisteem, wat oplossings vir hierdie lae saturasie en perfusie beperkings voorstel, word in hierdie studie aangebied. Die voorgestelde sisteem is ontwerp om die lae perfusie beperkings te oorkom deur 'n kunsmatige polsslag in die 'photoplethysmograph' te induseer. 'n Nuwe arterio-veneuse hipotese is geformuleer om arteriële en veneuse saturasie inligting uit hierdie kunsmatige polsslag te onttrek deur middel van 'n arteriële-teenoor-veneuse styfheids verhouding. Die gol engtes wat gebruik is in die sensors, is spesi ek gekies om hoë en lae saturasie akkuraatheid te verskaf. 'n In vitro kalibrasie prosedure is gevolg om die sensors vir hoë en lae saturasie te kalibreer, waarna die werkverrigting van die sisteem getoets is deur middel van 'n in vivo validasie prosedure. Die in vivo resultate toon goeie akkuraatheid vir hoë saturasie, met beperkte akkuraatheid vir lae saturasie. Die arterio-veneuse hipotese is gevalideer, wat aandui dat veneuse saturasie wel uit die kunsmatige 'photoplethysmograph' onttrek kan word. Alhoewel die resultate wat in hierdie studie aangebied word nie omvattend of beslissend is nie, dui dit egter aan dat die voorgestelde sisteem dalk in staat kan wees om arteriële en veneuse saturasie in uiters lae perfusie gevalle te meet. Verbeteringe sal egter aan die sisteem aangebring moet word in terme van hardeware en kalibrasie, om 'n meer gestandardiseerde metings metode te verseker. Verdere navorsing oor die werkverrigting van die voorgestelde sisteem word ook voorgestel.
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Marks, Damian. "Investigation of the feasibility of non-invasive carbon dioxide detection using spectroscopy in the visible spectrum." Thesis, University of North Texas, 2007. https://digital.library.unt.edu/ark:/67531/metadc6142/.
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Pulse oximeters are used in operating rooms and recovery rooms as a monitoring device for oxygen in the respiratory system of the patient. The advantage of pulse oximeters over other methods of oxygen monitoring is that they are easy to use and they are non-invasive, which means it is not necessary break the skin to extract blood for information to be obtained. The standard for the measurement of partial pressure of CO2 and O2 is an arterial blood gas analysis (ABG). However routine monitoring using this method on a continuous basis is impractical since it is slow, painful and invasive. Measuring carbon dioxide is critical to preventing ailments such as carbon dioxide poisoning or hypoxia. The problem is, currently there is no known effective non-invasive method for accurately measuring carbon dioxide in the body to properly assess the adequacy of ventilation. The objective of this study was to experimentally use spectroscopy in the visible spectrum and the principles of operation of a pulse oximeter to incorporate a method of non-invasive real-time carbon dioxide monitoring that is as quick and easy to use.
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Shah, Syed Ahmar. "Vital sign monitoring and data fusion for paediatric triage." Thesis, University of Oxford, 2012. http://ora.ox.ac.uk/objects/uuid:80ae66e3-849b-4df1-b064-f9eb7530200d.
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Accurate assessment of a child’s health is critical for appropriate allocation of medical resources and timely delivery of healthcare in both primary care (GP consultations) and secondary care (ED consultations). Serious illnesses such as meningitis and pneumonia account for 20% of deaths in childhood and require early recognition and treatment in order to maximize the chances of survival of affected children. Due to time constraints, poorly defined normal ranges, difficulty in achieving accurate readings and the difficulties faced by clinicians in interpreting combinations of vital signs, vital signs are rarely measured in primary care and their utility is limited in emergency departments. This thesis aims to develop a monitoring and data fusion system, to be used in both primary care and emergency department settings during the initial assessment of children suspected of having a serious infection. The proposed system relies on the photoplethysmogram (PPG) which is routinely recorded in different clinical settings with a pulse oximeter using a small finger probe. The most difficult vital sign to measure accurately is respiratory rate which has been found to be predictive of serious infection. An automated method is developed to estimate the respiratory rate from the PPG waveform using both the amplitude modulation caused by changes in thoracic pressure during the respiratory cycle and the phenomenon of respiratory sinus arrhythmia, the heart rate variability associated with respiration. The performance of such automated methods deteriorates when monitoring children as a result of frequent motion artefact. A method is developed that automatically identifies high-quality PPG segments mitigating the effects of motion on the estimation of respiratory rate. In the final part of the thesis, the four vital signs (heart rate, temperature, oxygen saturation and respiratory rate) are combined using a probabilistic framework to provide a novelty score for ranking various diagnostic groups, and predicting the severity of infection in two independent data sets from two different clinical settings.
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Keck, Christian. "Oximether-verbrückte Liganden auf Zuckerbasis in der stereoselektiven Hydrierung von Folsäure." [S.l. : s.n.], 2005. http://deposit.ddb.de/cgi-bin/dokserv?idn=974203513.
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East, Christine Elizabeth. "Fetal intrapartum pulse oximetry /." [St. Lucia, Qld.], 2006. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe19387.pdf.
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Schönherr, Maximilian. "Glucose- und Galactose-Oximether in der enantioselektiven Katalyse." [S.l.] : [s.n.], 2002. http://deposit.ddb.de/cgi-bin/dokserv?idn=965506517.
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West, Ian Philip. "Optical fibre based pulse oximetry." Thesis, University of Liverpool, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.262607.
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de, Kock J. P. "Pulse oximetry : theoretical and experimental models." Thesis, University of Oxford, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.302928.
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Scott, Valerie Anne. "An investigation into retinal pulse oximetry." Thesis, University of Oxford, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.306934.
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Mordant, D. J. "Human retinal oximetry using spectral imaging." Thesis, University College London (University of London), 2012. http://discovery.ucl.ac.uk/1346478/.
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The principal aim of the research described in this thesis was to develop a technique of non-invasively measuring the oxygen saturation within the retinal vasculature of human subjects (retinal oximetry). The evaluation of a hyperspectral fundus camera used to acquire retinal images in different wavelengths of visible light, and the image analysis techniques used to perform retinal oximetry are described. Validation of the oximetry techniques was performed using an artificial eye containing human blood of known oxygen saturation: the calculated oxygen saturation was compared to the gold standard measurement. The mean differences between the calculated and measured oxygen saturations were small. Hyperspectral imaging/oximetry of normal subjects was performed to characterize the oximetric features of the retinal vasculature. The mean oxygen saturation (± SD) of the temporal retinal arterioles and venules were 110.8% (± 11.8%) and 27.7% (± 3.2%) respectively. The application of the retinal oximetry technique was explored in patients with retinal arterial and venous occlusion to determine whether oximetric changes in the retinal vasculature could be detected. Variation in measured oxygen saturation of the retinal arterioles and venules respectively were apparent, and corresponded with angiographic features of retinal capillary loss. The techniques were applied to patients with asymmetrical primary open angle glaucoma to determine whether oximetric changes could be detected. The mean oxygen saturation of the temporal retinal venules were significantly higher [44.8% (± 24.2%)] in the more advanced glaucomatous eyes compared to normal subjects. Hyperoxia of the retinal venules suggests reduced oxygen consumption as a consequence of inner retinal dysfunction in glaucoma. However, because of the small sample size, further research on a larger population of subjects is required to support this finding. Hyperspectral imaging could be used to detect oximetric abnormalities in the retinal vasculature in patients with retinovascular occlusion and glaucoma.
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Azorin-Peris, Vicente. "Opto-physiological modelling of pulse oximetry." Thesis, Loughborough University, 2008. https://dspace.lboro.ac.uk/2134/22498.
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Since its conception decades ago, pulse oximetry-the non-invasive measurement of arterial blood oxygen saturation in real-time-has proven its worth by achieving and maintaining its rank as a compulsory standard of patient monitoring. However, the use of oversimplified models to describe and implement the technology has limited its applicability and has had its evolution at a near standstill for the past decade. Currently available technology relies on empirical calibrations that consist of the correlation between simultaneous measurements from pulse oximeters and invasively acquired arterial blood samples from test subjects, mainly because the mathematical models underlying the technology are not sufficiently descriptive and accurate. Advances in knowledge of human tissue optical properties, computing power and sensing technology all contribute to a new realm of expansion for pulse oximetry modelling. This research project aims to develop a methodology for improving optophysiological models of pulse oximetry through the use of a validated Monte Carlo simulation platform for optical propagation in arbitrary geometries. The platform aims to arrive at a model that can predict the widest range of empirical outcomes while maintaining the highest possible level of accuracy. To this end, an empirical platform and a corresponding experimental protocol is developed towards an increasingly repeatable standard, thus providing an empirical output for validation of simulated data. Subsequently, the parameters and coefficients of the optophysiological model at the core of the simulation platform are iterated until a high level of correlation is achieved in their outputs. This gives way to a new approach to the opto-physiological modelling of pulse oximetry.
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Alabboud, Ied. "Human retinal oximetry using hyperspectral imaging." Thesis, Heriot-Watt University, 2009. http://hdl.handle.net/10399/2297.
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The aim of the work reported in this thesis was to investigate the possibility of measuring human retinal oxygen saturation using hyperspectral imaging. A direct non-invasive quantitative mapping of retinal oxygen saturation is enabled by hyperspectral imaging whereby the absorption spectra of oxygenated and deoxygenated haemoglobin are recorded and analysed. Implementation of spectral retinal imaging thus requires ophthalmic instrumentation capable of efficiently recording the requisite spectral data cube. For this purpose, a spectral retinal imager was developed for the first time by integrating a liquid crystal tuneable filter into the illumination system of a conventional fundus camera to enable the recording of narrow-band spectral images in time sequence from 400nm to 700nm. Postprocessing algorithms were developed to enable accurate exploitation of spectral retinal images and overcome the confounding problems associated with this technique due to the erratic eye motion and illumination variation. Several algorithms were developed to provide semi-quantitative and quantitative oxygen saturation measurements. Accurate quantitative measurements necessitated an optical model of light propagation into the retina that takes into account the absorption and scattering of light by red blood cells. To validate the oxygen saturation measurements and algorithms, a model eye was constructed and measurements were compared with gold-standard measurements obtained by a Co-Oximeter. The accuracy of the oxygen saturation measurements was (3.31%± 2.19) for oxygenated blood samples. Clinical trials from healthy and diseased subjects were analysed and oxygen saturation measurements were compared to establish a merit of certain retinal diseases. Oxygen saturation measurements were in agreement with clinician expectations in both veins (48%±9) and arteries (96%±5). We also present in this thesis the development of novel clinical instrument based on IRIS to perform retinal oximetry.
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Echiadis, Angelos S. "Development and evaluation of venous oximetry." Thesis, Loughborough University, 2007. https://dspace.lboro.ac.uk/2134/35539.
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Photoplethysmography, a technique to measure by optical means volume changes, has been known and applied for many years. One of its most popular applications is pulse oximetry, a non-invasive method to measure oxygen content in arterial blood. It is based on the principle of arterial blood volume changes due to heart contractions, known as systoles. Systolic pulsations appear on the arterial vascular system, while blood flow in veins does not normally present pulsations, especially at remote parts of the peripheral vascular system, such as the fingers. Therefore, pulse oximetry is only applicable to arteries as their pulsations allow for separation of the pulsatile components from the rest of the absorbing components. A novel non-invasive technique permits the measurement of venous oxygen saturation by introducing a series of pulsations in the veins thus allowing the separation of venous signal components for calculation of venous oxygen saturation. This thesis presents a theoretical model describing the mechanical coupling of arteries and veins and its effects in the accuracy of oxygen saturation measurement.
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Forsyth, Jason B. "Wearable Pulse Oximetry in Construction Environments." Thesis, Virginia Tech, 2010. http://hdl.handle.net/10919/31668.
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The goal of this project was to determine the feasibility of non-invasively monitoring the blood gases of construction workers for carbon monoxide exposure via pulse oximetry. In particular, this study sought to understand the impact of motion artifacts caused by the worker's activities and to determine if those activities would prevent the blood gas sensor from detecting the onset of carbon monoxide poisoning. This feasibility study was conducted using a blood oxygen sensor rather than a blood carbon monoxide sensor for several reasons. First, blood gas sensors that measure blood carbon monoxide are not readily available in suitable physical form factors. Second, sensors for blood oxygen and blood carbon monoxide operate on the same physical principles and thus will be affected in the same way by worker motions. Finally, using a blood oxygen sensor allowed the study to be conducted without exposing the human subjects to carbon monoxide. A user study was conducted to determine the distribution of motion artifacts that would be created during a typical work day. By comparing that distribution to a worst-case estimate of time to impairment, the probability that helmet will adequately monitor the worker can be established. The results of the study show that the helmet will provide a measurement capable of warning the user of on setting carbon monoxide poisoning with a probability greater than 99%.Master of Science
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Vasudevan, Shanthi. "Simultaneous Measurement of Oxygen and Carbon Monoxide Saturation using Pulse Oximeters." Digital WPI, 2011. https://digitalcommons.wpi.edu/etd-theses/330.
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The ability of pulse oximeters to measure carboxyhemoglobin (HbCO) in blood or measure accurate values of oxygen saturation (SpO2) in the presence of elevated levels of HbCO is an important advantage because high exposure to carbon monoxide (CO) can be fatal or results in permanent neurological damage. The aim of my research was to develop an algorithm that would measure SpO2 and SpCO simultaneously using a pulse oximeter. Several specific wavelengths at which changes in SpCO and SpO2 can be measured with high sensitivity and specificity were identified. The choice of these wavelengths was experimentally verified utilizing an in-vitro set up. Preliminary results using our algorithm showed an accuracy of -1.1 to +2.7% [±1.96 SD] for SpO2 ranging between 70-100%, and -2 to 3.3% [±1.96 SD] for SpCO ranging between 30% with a specificity of 83.3% and a sensitivity of 100% for SpO2 and SpCO, respectively.
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MacKenzie, Lewis Edward. "In vivo microvascular oximetry using multispectral imaging." Thesis, University of Glasgow, 2016. http://theses.gla.ac.uk/7732/.
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This thesis describes the application of multispectral imaging to several novel oximetry applications. Chapter 1 motivates optical microvascular oximetry, outlines oxygen transport in the body, describes the theory of oximetry, and describes the challenges associated with in vivo oximetry, in particular imaging through tissue. Chapter 2 reviews various imaging techniques for quantitative in vivo oximetry of the microvasculature, including multispectral and hyperspectral imaging, photoacoustic imaging, optical coherence tomography, and laser speckle techniques. Chapter 3 describes a two-wavelength oximetry study of two microvascular beds in the anterior segment of the eye: the bulbar conjunctival and episcleral microvasculature. This study reveals previously unseen oxygen diffusion from ambient air into the bulbar conjunctival microvasculature, altering the oxygen saturation of the bulbar conjunctiva. The response of the bulbar conjunctival and episcleral microvascular beds to acute mild hypoxia is quantified and the rate at which oxygen diffuses into bulbar conjunctival vessels is measured. Chapter 4 describes the development and application of a highly novel non-invasive retinal angiography technique: Oximetric Ratio Contrast Angiography (ORCA). ORCA requires only multispectral imaging and a small perturbation of blood oxygen saturation to produce angiographic sequences. A pilot study of ORCA in human subjects was conducted. This study demonstrates that ORCA can produce angiographic sequences with features such as sequential vessel filling and laminar flow. The application and challenges of ORCA are discussed, with emphasis on comparison with other angiography techniques, such as fluorescein angiography. Chapter 5 describes the development of a multispectral microscope for oximetry in the spinal cord dorsal vein of rats. Measurements of blood oxygen saturation are made in the dorsal vein of both healthy rats, and in rats with the Experimental autoimmune encephalomyelitis (EAE) disease model of multiple sclerosis. The venous blood oxygen saturation of EAE disease model rats was found to be significantly lower than that of healthy controls, indicating increased oxygen uptake from blood in the EAE disease model of multiple sclerosis. Chapter 6 describes the development of video-rate red eye oximetry; a technique which could enable stand-off oximetry of the blood-supply of the eye with high temporal resolution. The various challenges associated with video-rate red eye oximetry are investigated and their influence quantified. The eventual aim of this research is to track circulating deoxygenation perturbations as they arrive in both eyes, which could provide a screening method for carotid artery stenosis, which is major risk-factor for stroke. However, due to time constraints, it was not possible to thoroughly investigate if video-rate red eye can detect such perturbations. Directions and recommendations for future research are outlined.
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Glaros, Konstantinos N. "Low-power pulse oximetry and transimpedance amplifiers." Thesis, Imperial College London, 2011. http://hdl.handle.net/10044/1/9480.
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This work focuses on the design of low-power fully-integrated pulse oximeter front-ends and transimpedance amplifiers. Mathematical modelling and numerical simulations are employed to systematically quantify the trade-offs involved in the design of such a front-end and investigate the specific challenges arising from the requirements for low- power and full integration. The response speed, stability, power consumption and noise characteristics of the front-end's transimpedance amplifier are identified as significant points of interest. The performance of several transimpedance amplifier topologies is investigated. Topologies based on switched integration of the input are shown to be advantageous and employed in the design of a mixed-signal pulse oximeter front-end which was fabricated in the AMS 0:35 m technology. Extensive electrical and physiological measurements are reported showing that the proposed front-end can achieve LED power consumptions below 400 W and a total power consumption of less than 1 mW with a mean signal-to-noise ratio exceeding 39 dB at the detector. This performance is among the best ever reported and an order of magnitude better than most commercial pulse oximeters. Ways to lower this power consumption even further are identified. This work also reports on a novel self-biased photoreceptor (transimpedance amplifier) topology. A detailed comparison with previous state-of-the-art designs is carried out that provides new, useful insights on the photoreceptors' performance. The proposed design is concluded to be beneficial for applications where extremely low power and fast settling are of high significance.
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Johnston, William S. "Development of a signal processing library for extraction of SpO2, HR, HRV, and RR from photoplethysmographic waveforms." Worcester, Mass. Worcester Polytechnic Institute, 2006. http://www.wpi.edu/Pubs/ETD/Available/etd-073106-130906/.
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Thesis (M.S.)--Worcester Polytechnic Institute.Keywords: wearable medical sensors; arterial oxygen saturation; software development; embedded systems; heart rate; respiration rate; heart rate variability; pulse oximetry; digital signal processing Includes bibliographical references (leaves 125-133).
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Cloete, Garth. "Non-invasive artificial pulse oximetry : development & testing." Thesis, Stellenbosch : Stellenbosch University, 2012. http://hdl.handle.net/10019.1/19947.
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Thesis (MScEng)--Stellenbosch University, 2012.ENGLISH ABSTRACT: The monitoring of patients in healthcare is of prime importance to ensure their efficient treatment. The monitoring of blood oxygen saturation in tissues affected by diseases or conditions that may negatively affect the function is a field that has grown in importance in recent times. This study involved the development and testing of a highly sensitive noninvasive blood oxygen saturation device. The device can be used to continuously monitor the condition of tissue affected by diseases which affect the blood flow through the tissue, and the oxygen usage in tissue. The device’s system was designed to specifically monitor occluded tissue which has low oxygen saturations and low perfusion. With the use of the device, it is possible to monitor the status of tissue affected by diseases such as meningococcemia and diabetes mellitus or conditions such as the recovery after plastic surgery. The study delved into all aspects involved in the development of a non-invasive artificial pulse oximeter, including but not limited to that of a detailed device design, signals analysis, animal in-vivo and laboratory in-vitro system design for the calibration of the system as well as human clinical validation and testing procedures. All these aspects were compared to determine the relative accuracies of the different models. Through testing it was shown that it is possible to non-invasively measure the mixed oxygen saturation in occluded tissue. However, without accurate validation techniques and methods of obtaining both arterial and venous blood samples in occluded tissue the system could not be fully validated for determining both the arterial and venous oxygen saturations in the human invivo study. Although the system was unable to accurately measure specifically the venous oxygenation it was able to measure the mixed oxygen saturation. With further research it would be possible to validate the system for measuring both the arterial and venous oxygen saturations.
AFRIKAANSE OPSOMMING: Die monitering van pasiënte in gesondheidsorg is van uiterste belang om doeltreffende behandeling te verseker. Die monitering van bloedsuurstofversadiging in weefsels wat geaffekteer word deur siektes of toestande wat ’n negatiewe impak kan hê op die funksie daarvan is ’n gebied wat aansienlike groei getoon het in die onlangse verlede. Die studie het die ontwikkeling en toetsing van ’n hoogs sensitiewe nieindringende bloedsuurstofversadigingsensor ingesluit. Hierdie sensor kan gebruik word om deurentyd die toestand van weefsel te monitor wat geaffekteer word deur siektes wat bloedvloei deur weefsel affekteer sowel as die suurstofgebruik in die weefsel. Die stelsel is ontwerp om spesifiek die ingeslote weefsel wat lae suurstofversadiging en lae perfusie het, te monitor. Deur gebruik te maak van die toestel is dit moontlik om die toestand van die weefsel wat geaffekteer word deur siektes soos meningococcemia en diabetes mellitus of toestande soos die herstel na plastiese sjirurgie te monitor. Die studie het gekyk na alle aspekte wat betrokke is in die ontwikkeling van ’n nie-indringende kunsmatige pols-oksimeter, insluitend maar nie beperk tot gedetailleerde ontwerp nie, sein analise, dier in-vivo en laboratorium in-vitro stelselontwerp vir die kalibrasie van die stelsel sowel as menslike kliniese bekragtiging en toetsprosedures. Al hierdie aspekte is vergelyk om die relatiewe akkuraatheid van die verskillende modelle te bepaal. Die toetse het gewys dat dit moontlik is om nie-indringend die gemengde suurstofversadiging in weefsel te bepaal. Sonder akkurate bekragtigingstegnieke en metodes om beide arteriële en vene bloedmonsters te versamel in ingeslote weefsel kan die stesel nie ten volle bekragtig word om beide arteriële- en veneversadigings in menslike in-vivo studie te bepaal nie. Hoewel die stelsel nie ’n akkurate meting van die aarsuurstof kon kry nie, is daar wel ’n akkurate meting geneem van die gemengde suurstofversadiging. Toekomstige navorsing kan lei tot die bekragtiging van die stelsel om beide arteriële en slagaar suurstofversadigings te meet.
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Meenakshisundaram, Guruguhan. "Development of novel implantable sensors for biomedical oximetry." Columbus, Ohio : Ohio State University, 2008. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1217427728.
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Tavakoli, Dastjerdi Maziar 1976. "An analog VLSI front end for pulse oximetry." Thesis, Massachusetts Institute of Technology, 2006. http://hdl.handle.net/1721.1/36184.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2006.Includes bibliographical references (p. 210-216).
Pulse oximetry is a fast, noninvasive, easy-to-use, and continuous method for monitoring the oxygen saturation of a patient's blood. In modem medical practice, blood oxygen level is considered one of the important vital signs of the body. The pulse oximeter system consists of an optoelectronic sensor that is normally placed on the subject's finger and a signal processing unit that computes the oxygen saturation. It uses red and infrared LEDs to illuminate the subject's finger. We present an advanced logarithmic photoreceptor which takes advantage of techniques such as distributed (cascaded) amplification, automatic loop gain control, and parasitic capacitance unilateralization to improve the performance and ameliorate certain shortcomings of existing logarithmic photoreceptors. These improvements allow us to reduce LED power significantly because of a more sensitive photoreceptor. Furthermore, the exploitation of the logarithmic nonlinearity inherent in transistors eliminates the need of performing some of the mathematical operations which are traditionally done in digital domain to calculate oxygen saturation and allows for a very area-efficient all-analog implementation. The need for an ADC and a DSP is thus completely eliminated.
(cont.) We show that our analog pulse oximeter constructed with red and infrared LEDs and our novel photoreceptor at its front end consumes 4.8mW of power whereas a custom-designed ASIC digital implementation (employing a conventional linear photoreceptor) and the best commercial pulse oximeter are estimated to dissipate 15.7mW and 55mW, respectively. The direct result of such power efficiency is that while the batteries in this commercial oximeter need replacement every 5 days (assuming four "AAA" 1.5V batteries are used), our analog pulse oximeter allows 2 months of operation. Therefore, our oximeter is well suited for portable medical applications such as continuous home-care monitoring for elderly or chronic patients, emergency patient transport, remote soldier monitoring, and wireless medical sensing.
by Maziar Tavakoli Dastjerdi.
Ph.D.