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1
Hammer, J., and C. J. Newth. "Effect of lung volume on forced expiratory flows during rapid thoracoabdominal compression in infants." Journal of Applied Physiology 78, no. 5 (1995): 1993–97. http://dx.doi.org/10.1152/jappl.1995.78.5.1993.
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The rapid thoracoabdominal compression (RTC) technique is commonly used in pulmonary function laboratories to assess flow-volume relationships in infants unable to produce a voluntary forced expiration maneuver. This technique produces forced expiratory flows over only a small lung volume segment (i.e., tidal volume). It has been argued that the RTC technique should be modified to measure flow-volume relationships over a larger portion of the vital capacity range to imitate the voluntary maximal forced expiratory maneuver obtained in older children and adults. We examined the effect of volume history on forced expiratory flows by generating forced expiratory flow-volume curves by RTC from well-defined inspiratory volumes delineated by inspiratory pressures of 10, 20, 30, and 40 cmH2O down to residual volume (i.e., the reference volume) in seven intubated and anesthetized infants with normal lungs [age 8.0 +/- 2.0 (SE) mo, weight 6.7 +/- 0.6 kg]. We compared maximal expiratory flows at isovolume points (25 and 10% of forced vital capacity) and found no significant differences in maximal isovolume flow rates measured from the different lung volumes. We conclude that there is no obvious need to initiate RTC from higher lung volumes if the technique is used for flow comparisons. However, compared with measurements of maximal flows at functional residual capacity by RTC from end-tidal inspiration, the initiation of RTC from a defined and reproducible inspiratory level appears to decrease the intrasubject variability of the maximal expiratory flows at low lung volumes.
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Koulouris, Nickolaos G., Georgios Kaltsakas, Anastasios F. Palamidas, and Sofia-Antiopi Gennimata. "Methods for Assessing Expiratory Flow Limitation during Tidal Breathing in COPD Patients." Pulmonary Medicine 2012 (2012): 1–8. http://dx.doi.org/10.1155/2012/234145.
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Patients with severe COPD often exhale along the same flow-volume curve during quite breathing as during forced expiratory vital capacity manoeuvre, and this has been taken as indicating expiratory flow limitation at rest (EFLT). Therefore,EFLT, namely, attainment of maximal expiratory flow during tidal expiration, occurs when an increase in transpulmonary pressure causes no increase in expiratory flow.EFLTleads to small airway injury and promotes dynamic pulmonary hyperinflation with concurrent dyspnoea and exercise limitation. In fact,EFLToccurs commonly in COPD patients (mainly in GOLD III and IV stage) in whom the latter symptoms are common. The existing up-to-date physiological methods for assessing expiratory flow limitation (EFLT) are reviewed in the present work. Among the currently available techniques, the negative expiratory pressure (NEP) has been validated in a wide variety of settings and disorders. Consequently, it should be regarded as a simple, non invasive, most practical, and accurate new technique.
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Le Souef, P. N., D. M. Hughes, and L. I. Landau. "Effect of compression pressure on forced expiratory flow in infants." Journal of Applied Physiology 61, no. 5 (1986): 1639–46. http://dx.doi.org/10.1152/jappl.1986.61.5.1639.
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The effect of the force of compression on expiratory flow was evaluated in 19 infants (2-13 mo of age) with respiratory illnesses of varying severity. An inflatable cuff was used to compress the chest and abdomen. Expiratory flow and volume, airway occlusion pressure, cuff pressure (Pc), and functional residual capacity were measured. Transmission of pressure from cuff to pleural space was assessed by a noninvasive occlusion technique. Close correlations (P less than 0.001) were found between Pc and the change in pleural pressure with cuff inflation (delta Ppl,c). Pressure transmission was found to vary between two cuffs of different design and between infants. Several forced expirations were then performed on each infant at various levels of delta Ppl,c. Infants with low maximal expiratory flows at low lung volumes required relatively gentle compression to achieve flow limitation and showed decreased flow for firmer compressions. Flow-volume curves in each infant tended to become more concave as delta Ppl,c increased. These findings underline the importance of knowledge of delta Ppl,c in interpreting expiratory flow-volume curves in infants.
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Lai, Y. L., and H. C. Chou. "Respiratory mechanics and maximal expiratory flow in the anesthetized mouse." Journal of Applied Physiology 88, no. 3 (2000): 939–43. http://dx.doi.org/10.1152/jappl.2000.88.3.939.
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Mice have been widely used in immunologic and other research to study the influence of different diseases on the lungs. However, the respiratory mechanical properties of the mouse are not clear. This study extended the methodology of measuring respiratory mechanics of anesthetized rats and guinea pigs and applied it to the mouse. First, we performed static pressure-volume and maximal expiratory flow-volume curves in 10 anesthetized paralyzed C57BL/6 mice. Second, in 10 mice, we measured dynamic respiratory compliance, forced expiratory volume in 0.1 s, and maximal expiratory flow before and after methacholine challenge. Averaged total lung capacity and functional residual capacity were 1.05 ± 0.04 and 0.25 ± 0.01 ml, respectively, in 20 mice weighing 22.2 ± 0.4 g. The chest wall was very compliant. In terms of vital capacity (VC) per second, maximal expiratory flow values were 13.5, 8.0, and 2.8 VC/s at 75, 50, and 25% VC, respectively. Maximal flow-static pressure curves were relatively linear up to pressure equal to 9 cmH2O. In addition, methacholine challenge caused significant decreases in respiratory compliance, forced expiratory volume in 0.1 s, and maximal expiratory flow, indicating marked airway constriction. We conclude that respiratory mechanical parameters of mice (after normalization with body weight) are similar to those of guinea pigs and rats and that forced expiratory maneuver is a useful technique to detect airway constriction in this species.
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Boccaccino, Alfredo, Diego G. Peroni, Angelo Pietrobelli, et al. "Assessment of variable obstruction by forced expiratory volume in 1 second, forced oscillometry, and interrupter technique." Allergy and Asthma Proceedings 28, no. 3 (2007): 331–35. http://dx.doi.org/10.2500/aap.2007.28.2963.
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Goswami, Sushmita, Javid H. Sagar, and G. Varadharajulu. "Impact of Thera-Pep and Forced Expiratory Technique in Chronic Bronchitis Patients." Indian Journal of Public Health Research & Development 11, no. 1 (2020): 660. http://dx.doi.org/10.37506/v11/i1/2020/ijphrd/193899.
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Dellacà, R. L., P. Santus, A. Aliverti, et al. "Detection of expiratory flow limitation in COPD using the forced oscillation technique." European Respiratory Journal 23, no. 2 (2004): 232–40. http://dx.doi.org/10.1183/09031936.04.00046804.
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Akita, Takefumi, Toshihiro Shirai, Kazutaka Mori, et al. "Association of the forced oscillation technique with negative expiratory pressure in COPD." Respiratory Physiology & Neurobiology 220 (January 2016): 62–68. http://dx.doi.org/10.1016/j.resp.2015.09.002.
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Dr., S. Nagaraja, B. Gajanana Prabhu Dr., and S. M. Prakash Dr. "AN ASSESSMENT OF MEASURED AND SELF-PERCEIVED FORCED EXPIRATORY VOLUME PER SECOND AND PEAK EXPIRATORY FLOW LITER PER MINUTE AMONG HEARING AND VISUALLY IMPAIRED CHILDREN." International Journal of Multidisciplinary Research and Modern Education (IJMRME) 6, no. 1 (2020): 34–39. https://doi.org/10.5281/zenodo.3817142.
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The present situation people with hearing and visual impairment need more support in their physical and psychosocial improvement. Child with visual and hearing impairment is not only face a lot of individual hardships during his premature developing years but also face a many problems and challenges to the responsible adults in his life. The intention of the current examination was to measure the lung capacity of hearing and visually impaired special school children of Karnataka state. Further the level of perception on forced expiratory volume per second and peak expiratory flow volume per minute was also correlated with their actual status. The present study was conducted on four hundred and fourteen (N=414) hearing and visually impaired special school children selected through purposive random sampling technique. The study included adolescents with hearing impairment one hundred and seventy one (N=171) and vision impairment two hundred and forty three (N=243) in male group. Complete subjects were residents of special schools within Karnataka state. Their age ranged between 13 to 18 years. The forced expiratory volume per second and peak expiratory flow volume per minute measurement was done by following the standard procedure. The level of perception on forced expiratory volume per second and peak expiratory flow volume per minute of hearing and visually impaired school children was done using a 3 point likert scale. The forced expiratory volume per second of 13 to 14 years with 2.01 ± 0.48; 2.39 ± 0.46 in 15 to 16 years; and 2.58 ± 0.52 in 17 to 18 years. The peak expiratory flow volume per minute was 290.36 ± 68.99 in 13 to 14 years; 326.95 ± 75.09 in 15 to 16 years; and 352.18 ± 87.00 in 17 to 18 years. On the basis of the findings of the current examination it is concluded that the hearing and visually impaired school going children poor forced expiratory volume per second and peak expiratory flow volume per minute is an indication of lower lung capacity level. Since hearing and visually impaired school going children require to perform their everyday physical exercise at their own, it is imperative to have enough lung capacity. Further, the hearing and visually impaired school children under examination are unable to significantly weak positive linear relationship their lung capacity precisely.
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Hammer, J., and C. J. Newth. "Effort and volume dependence of forced-deflation flow-volume relationships in intubated infants." Journal of Applied Physiology 80, no. 1 (1996): 345–50. http://dx.doi.org/10.1152/jappl.1996.80.1.345.
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The application of negative pressure to the airway opening [called the forced-deflation (FD) technique] allows the examination of maximal expiratory flow-volume curves in intubated infants who are unable to generate a voluntary maximal expiratory maneuver. We explored the questions of effort and volume dependence of flows generated by FD in 18 intubated, sedated, and paralyzed infants [age 10.6 +/- 2.0 (SE) mo; weight 7.2 +/- 0.7 kg] with normal lungs. Effort dependence was assessed by isovolume pressure-flow curves that were constructed in 10 infants from repeated FD maneuvers from total lung capacity (defined as +40 cmH2O) by varying airway opening pressures from 0 (barometric pressure) to -100 cmH2O at intervals of 20 cmH2O. The effect of volume history was assessed by initiating FD maneuvers from different inspiratory volumes delineated by the inspiratory pressures +10, +20, +30, and +40 cmH2O. We compared maximal expiratory flows at isovolume points [50, 25, and 10% forced vital capacity (FVC) of the standard +40/-40 cmH2O FD maneuver] and found that flow limitation consistently occurred in all infants at and below 25% FVC with -40 cmH2O or greater airway opening pressure. We found no significant influence of volume history on maximal flows at and below 25% FVC. Under well-controlled study conditions, we demonstrated excellent reproducibility of maximal expiratory flows at low lung volumes, analogous to those of voluntary forced expiratory maneuvers in adults and older children. This information may be helpful in setting standards for performance and interpretation of FD maneuvers in intubated infants.
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Vaishnav, Bhumika T., and Tushar V. Tonde. "A study of pulmonary function abnormalities in obese individuals." International Journal of Research in Medical Sciences 8, no. 3 (2020): 811. http://dx.doi.org/10.18203/2320-6012.ijrms20200520.
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Background: Previous studies suggest that obese individuals are prone to pulmonary function abnormalities. The aim of this study was to evaluate pulmonary function tests in obese individuals and to relate pulmonary abnormalities if any found to lipid abnormalities and to the extent and duration of obesity.Methods: This prospective study was done on 40 obese patients attending to Dr. D. Y. Patil Hospital, Mumbai with complaints of pulmonary functions during the period from January to December 2012. Pulmonary function test was done with the help of Jaegers pneumoscreen. The percentage of body fat was determined by using triceps skin fold thickness technique by using Vernier callipers. Fasting serum samples was collected to analyses cholesterol and triglycerides.Results: Female preponderance was seen in the study (57.5%). Forced expiratory volume, forced vital capacity, maximum mid expiratory flow rate was significantly reduced and the ratio of forced expiratory volume in one second to forced vital capacity was significantly increased in individuals who had abnormal pulmonary function. Decrease in pulmonary function was noted with increased levels of cholesterol and triglyceride but the correlation was not significant.Conclusions: Obese individuals although asymptomatic have significant lung function abnormality in the form of restrictive as well as obstructive pattern. Hence, reduction in the body weight may help in reversal of the pulmonary function indices.
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Huda Anjum, Naima Farooq, Saman Sheraz, Ghulam Saqulain, and Hadiqa Adnan. "Post-Laparotomy Pulmonary Complications in Blow Bottle versus Interdigital Breathing Technique: A Quasi-Experimental Study." Pakistan Armed Forces Medical Journal 74, no. 4 (2024): 1088–93. http://dx.doi.org/10.51253/pafmj.v74i4.6715.
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Objective: To analyze the impact of interdigital versus blow-bottle breathing exercises on spirometry, pulse oximetry and respiratory rate in post-laparotomy patients. Study Design: Quasi-experimental study. Place and Duration of Study: Riphah College of Rehabilitation Sciences, Riphah International University and Capital Hospital, Islamabad, Pakistan, from Apr to Aug 2018. Methodology: This quasi experimental study recruited 27 post laparotomy patients, male and female, aged between 25-45 years. Along with conventional treatment for both groups, Group-A (n=14) received interdigital breathing exercises and Group-B (n=13) was given blow-bottle breathing therapy. Effect on spirometry, pulse oximetry tests and respiratory rate on Day 1, 3 and 6 were recorded. Results: On 6th Day post-laparotomy, interdigital group (Group A) showed significantly higher median and mean ranks for oxygen saturation (OS) (p<0.001), rate of peek expiratory flow (p=0.000), forced expiratory volume (1 second) (p=0.018), forced vital capacity (p<0.001) and lower respiratory rate (p<0.001). Blow bottle breathing therapy revealed significantly higher mean for forced vital capacity (p=0.017), but was lower for Oxygen saturation (p<0.001) and respiratory rate (p<0.001). Conclusion: Our findings lead us to conclude that interdigital technique provides more benefit to post-laparotomy patient compared to blow bottle technique in effective management of pulmonary complications.
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Olséni, L., B. Midgren, Y. Hörnblad, and P. Wollmer. "Chest physiotherapy in chronic obstructive pulmonary disease: Forced expiratory technique combined with either postural drainage or positive expiratory pressure breathing." Respiratory Medicine 88, no. 6 (1994): 435–40. http://dx.doi.org/10.1016/s0954-6111(05)80046-0.
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Lagerstrand, L., K. Larsson, E. Ihre, O. Zetterstrom, and G. Hedenstierna. "Pulmonary gas exchange response following allergen challenge in patients with allergic asthma." European Respiratory Journal 5, no. 10 (1992): 1176–83. http://dx.doi.org/10.1183/09031936.93.05101176.
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Pulmonary gas exchange was studied in 8 patients with allergic asthma before and after allergen challenge. Ventilation-perfusion relationships were assessed by the multiple inert gas elimination technique and forced expiratory flow by conventional spirometry. Measurements were made before, 7-8 minutes, and 0.5, 2.5 and 5 hours after challenge. During baseline conditions all patients showed normal forced expiratory flow (FEV1 3.9 +/- 0.77 (SD) l) and gas exchange expressed as the dispersion of pulmonary blood flow, log SDQ (0.35 +/- 0.08), (one of the common descriptors of ventilation-perfusion (VA/Q) inequality). Immediately after challenge there were significant decreases in FEV1 (to 2.3 +/- 0.75 l) and arterial PO2 (from 13.1 +/- 0.9 to 9.5 +/- 1.2 kPa). The developed ventilation-perfusion inequalities were similar to those found in other asthma studies, i.e. mainly a broad (log SDQ increased to 0.73 +/- 0.30) and sometimes bimodal distribution of the perfusion. Thirty minutes after challenge FEV1 significantly improved to 3.2 +/- 1.18 l while log SDQ remained high (0.71 +/- 0.32). Two and a half hours after challenge log SDQ was reduced and almost normalized to 0.38 +/- 0.07. Five patients developed a late phase reaction with decreasing flow rates after 5 hours. Three of these patients also showed increased log SDQ. There was no clear relationship between gas exchange mismatch and reduced forced expiratory flow. The results support the hypothesis that reduced expiratory flow and gas exchange impairment are caused by different pathophysiological mechanisms.
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Verbanck, Sylvia, Daniël Schuermans, Manuel Paiva, and Walter Vincken. "Nonreversible conductive airway ventilation heterogeneity in mild asthma." Journal of Applied Physiology 94, no. 4 (2003): 1380–86. http://dx.doi.org/10.1152/japplphysiol.00588.2002.
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A multiple-breath washout technique was used to assess residual ventilation heterogeneity in the conductive and acinar lung zones of asthmatic patients after maximal β2-agonist reversibility. Reversibility was assessed in 13 patients on two separate visits corresponding to a different baseline condition in terms of forced expiratory volume in 1 s [FEV1; average FEV1 over 2 visits: 92 ± 21% of predicted (SE)]. On the visit corresponding to each patient's best baseline, 400 μg salbutamol led to normal acinar ventilation heterogeneity, normal FEV1, and normal peak expiratory flow; i.e., none was significantly different from that obtained in 13 matched controls. By contrast, conductive ventilation heterogeneity and forced expiratory flow after exhalation of 75% forced vital capacity remained significantly different from controls ( P ≤ 0.005 on both indexes). In addition, the degree of postdilation conductive ventilation heterogeneity was similar to what was previously obtained in asthmatic individuals with a 19% lower baseline FEV1and twofold larger acinar ventilation heterogeneity (Verbanck S, Schuermans D, Noppen M, Van Muylem A, Paiva M, and Vincken W. Am J Respir Crit Care Med 159: 1545–1550, 1999). We conclude that, even in the mildest forms of asthma, the most consistent pattern of non-β2-agonist-reversible ventilatory heterogeneity is in the conductive lung zone, most probably in the small conductive airways.
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Rekha, K., J. Vanitha, and Aishwarya Kiran. "Effect of respiratory muscle training with wind instrument among obese individuals." Biomedicine 41, no. 2 (2021): 287–93. http://dx.doi.org/10.51248/.v41i2.798.
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Introduction and Aim:One of the most utilized parts of the body when playing a wind instrument is diaphragm. It assists to blow air in and out of your lungs and into the instrument to create sound. Using controlled and measured breaths, the breathing and lung capacity could get improve. Even, music therapy, such as playing wind instrument has been used as a technique for managing and fastening recovery on a physical and emotional level.Therefore, aim of this study was to determine the effects of respiratory muscle training with wind instrument among obese individuals. The objective was to find out the effects of respiratory muscle training with wind instrument in improving maximum voluntary ventilation, forced expiratory volume in 1 second, forced vital capacity and reducing dyspnoea among obese individuals.
 
 Materials and Methods: Study included 40 individuals with obesity aged 18-30years. Participants were equally divided into 2 groups- A and B. Group A treated with wind instrument (flute) and group B treated with incentive spirometer, both the groups were treated for 5 days a week for 5 weeks in which 1 session per day for 40 minutes with 5 minutes of warm up, 10 minutes of breathing training, 20 minutes of intervention training program and 5 minutes of cool down. Both the groups were tested for maximum voluntary ventilation, forced expiratory volume in 1 second, forced vital capacity using spirometry and dyspnea was graded with modified borg scale as a pre-test and post-test.
 
 Results: The comparison of pre and post-test values of maximum voluntary ventilation, forced expiratory volume in 1 second, forced vital capacity and modified borg scale showed a statistically significant difference with p-value <0.0001. While comparing the post-test values of maximum voluntary ventilation, forced expiratory volume in 1 second, forced vital capacity and modified borg scale between group A and group B, group A showed higher result with statistical significant difference of p-value <0.0001.
 
 Conclusion: Playing a wind instrument was found to be more effective than respiratory training using an incentive spirometer.
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Huang, Yilin, and Yali Bo. "Effect of an airway clearance technique in the treatment of children with severe pneumonia." African Journal of Reproductive Health 29, no. 4 (2025): 142–49. https://doi.org/10.29063/ajrh2025/v29i4.13.
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This was a research study, mainly explored the effect of an airway clearance technique (ACT) in treating children with severe pneumonia. One hundred children with severe pneumonia who accepted therapy in Shulan (Hangzhou) Hospital Affiliated to Zhejiang Shuren University Shulan International Medical College from January 2023 to January 2024 were selected and randomly divided into a control group and observation group. The control group accepted anti-inflammatory, cough, phlegm and asthma treatment, while the observation group accepted ACT therapy including anti-inflammatory, cough, phlegm, and asthma treatment. As compared to the control group, the observation group presented better total effective rate, shorter cough and sputum relief time, defervescence time, length of hospital stay, lung rale and disappeareance time, and lung shadow disappearance time. The observation group also had higher peak expiratory flow (PEF), forced expiratory volume in 1 second (FEV1) and forced vital capacity (FVC) levels, higher cough reflex, secretion viscosity and secretion volume scores, higher arterial oxygen pressure (PaO2) and arterial oxygen saturation (SaO2) levels as well as lower levels of inflammatory markers. We conclude that, the clinical efficacy of ACT for treatment of children with severe pneumonia is remarkable, which can improve related symptoms, improve lung function and blood gas indices, repress inflammation, and promote airway recovery.
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Makhdoom Muhammad Hamza, Muhammad Abdullah, Zarish Younas, et al. "COMPARISON OF RESISTIVE BREATHING VERSUS INSPIRATORY HOLD TECHNIQUE IN PATIENTS WITH CHRONIC BRONCHITIS." Insights-Journal of Life and Social Sciences 3, no. 1 (2025): 116–24. https://doi.org/10.71000/snqpz295.
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Background: Chronic bronchitis, a subtype of chronic obstructive pulmonary disease (COPD), is a progressive condition characterized by persistent airway inflammation, excessive mucus production, and airflow limitation. Its global burden continues to rise due to environmental pollution, occupational hazards, and smoking. While pharmacological interventions provide symptomatic relief, pulmonary rehabilitation remains a cornerstone in disease management. Various respiratory training techniques have been utilized to improve lung function and prevent exacerbations, yet comparative research on their efficacy remains limited. Objective: This study aimed to compare the effects of resistive breathing and inspiratory hold techniques on pulmonary function in patients with chronic bronchitis. Methods: A total of 26 participants were recruited using non-probability consecutive sampling. After screening and obtaining informed consent, they were randomly allocated into two intervention groups: the resistive breathing group (n=13) and the inspiratory hold technique group (n=13). Participants performed assigned breathing exercises for six weeks, with measurements taken at baseline and post-intervention. Pulmonary function parameters, including forced expiratory volume in one second (FEV1), forced vital capacity (FVC), FEV1/FVC ratio, and peak expiratory flow rate (PEFR), were assessed using a digital spirometer. Dyspnea severity was evaluated using the Modified Borg Scale. Statistical analysis was conducted using the Mann-Whitney U test for inter-group comparisons and the Wilcoxon Signed Rank test for intra-group analysis. Results: The mean age of participants was 52.8±5.6 years. PEFR showed a statistically significant improvement in the resistive breathing group (mean rank: 17.81, sum rank: 231.50, p=0.004), while the inspiratory hold technique group demonstrated no significant change (mean rank: 9.19, sum rank: 119.50). No significant differences were observed in FEV1 (p=0.105), FVC (p=0.190), FEV1/FVC ratio (p=0.798), or dyspnea scores (p=0.275) between the two groups. Conclusion: Resistive breathing demonstrated greater efficacy in improving peak expiratory flow rates in chronic bronchitis patients, indicating its potential role in enhancing airway clearance. However, no significant changes were observed in other pulmonary parameters. Inspiratory hold technique did not produce measurable improvements, suggesting that its role in pulmonary rehabilitation for chronic bronchitis requires further investigation.
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Vooren, PH, and BC van Zomeren. "Reference values of total respiratory resistance, determined with the "opening" interruption technique." European Respiratory Journal 2, no. 10 (1989): 966–71. http://dx.doi.org/10.1183/09031936.93.02100966.
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In a large epidemiological survey of lung function the subjects performed maximum expiratory flow volume (MEFV) manoeuvres. They were also interviewed by trained interviewers using a standardized questionnaire. In a random subset of the subjects the resistance of the respiratory system was measured with the "opening" interruption technique, in which the mouth pressure before the end of the interruption period is divided by the flow shortly after the end of it. The subset contained men and women, and smokers as well as nonsmokers, 229 of whom were considered to be healthy because they had no history of complaints and a "normal" flow-volume curve. In this group mean inspiratory and expiratory resistances did not differ significantly (0.27 and 0.29 for men and 0.39 and 0.38 kPa.l-1.s for women). The averages of in- and expiratory resistance were 0.28 +/- 0.10 kPa.l-1.s for men and 0.39 +/- 0.11 kPa.l-1.s for women. The resistance values were slightly but significantly correlated with body height, FEV1 and MEF50, but not with smoking habits. Due to the considerable variability the method does not permit sharp discrimination between normal and abnormal subjects. However, it appears to be useful in histamine challenge testing, to detect and monitor bronchial asthma, being not subjected to the disturbing effect of forced ins- and expirations.
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McNamara, J. J., R. G. Castile, G. M. Glass, and J. J. Fredberg. "Heterogeneous lung emptying during forced expiration." Journal of Applied Physiology 63, no. 4 (1987): 1648–57. http://dx.doi.org/10.1152/jappl.1987.63.4.1648.
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Several lines of evidence suggest that the healthy mammalian lung empties homogeneously during a maximally forced deflation. Nonetheless, such behavior would appear to be implausible if for no other reason than that airway structure is known to be substantially heterogeneous among parallel pathways of gas conduction. To resolve this paradox we reexamined the degree to which lung emptying is homogeneous, and considered mechanisms that might control differential regional emptying. Twelve excised canine lungs were studied. Regional alveolar pressure relative to pleural pressure was used as an index of regional lung volume. By use of a capsule technique, alveolar pressure was measured simultaneously in each of six regions during flow-limited deflations; flow from the lung was measured plethysmographically. The standard deviation of interregional pressure differences, which was taken as an index of nonuniformity, was 0.0, 0.74, 0.64, and 0.90 cmH2O at mean recoil pressures of 30, 8.4, 4.5, and 2.1 cmH2O (0, 25, 50, and 75% expired vital capacity), indicating that interregional pressure differences increased more rapidly earlier in the deflation. When we examined the time rate of change of regional alveolar pressure as an index of regional flow, we observed an intricate pattern of differential regional behavior that was inapparent in the maximum expiratory flow-volume (MEFV) curve. The most plausible interpretation of these findings is that regions of the healthy excised canine lung empty heterogeneously to a small degree, but in an interdependent compensatory pattern that is inapparent in the configuration of the maximum expiratory flow-volume curve.
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A, Tamuno-Opubo, Zosa Ugbana Dienye, Rosemary Oluchi Stanley, Joy Tonye Wihioka, and Siyeofori Belema Dede. "Changes in Basic Pulmonary Indices of Obese Women Resident in Rivers State, Nigeria." Scholars International Journal of Anatomy and Physiology 6, no. 11 (2023): 173–76. http://dx.doi.org/10.36348/sijap.2023.v06i11.003.
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Obesity and pulmonary diseases are said to be co-prevalent and debilitating chronic illnesses that are becoming more and more commonplace globally. This study thus, evaluated the changes in basic pulmonary indices of obese women resident in Rivers State, Nigeria. The minimum sample size of 272 was determined using the Leslie Fischer's formula; exactly 334 obese and non-obese women within their 18 and 65 years of age with no critical health condition and resident in Upland and Riverine areas of Rivers State were actually surveyed by the present study. A multistage sampling technique was adopted, and subjects were surveyed across the upland and riverine locations of the State. These subjects were evenly drawn from the multi-ethnic residents of the state. Automated spirometer was used to measure forced vital capacity (FVC); forced expiratory volume in 1 second (FEV1 and forced expiratory volume in 1 second (FEV1) and forced expiratory volume in 6 second (FEV6) and the FEV1/FVC ratio. The quantitative data were subjected to statistical analyses using the statistical package for social sciences (SPSS) version 21.0. One-way analysis of variance (ANOVA) and independent t-test with a p< 0.05 considered statistically significant were determined. The result indicated that the obese subjects had reductions in some pulmonary indices, like FVC levels. On the other hand, the FVC/ FEV1 ratio had significant (p<0.05) increases following increasing BMI. Further evaluations on the actual impact of obesity on FVC/ FEV1 ratio may shade more light in this direction.
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Henschen, Matthias, Janet Stocks, Ah-Fong Hoo, and Paul Dixon. "Analysis of forced expiratory maneuvers from raised lung volumes in preterm infants." Journal of Applied Physiology 85, no. 5 (1998): 1989–97. http://dx.doi.org/10.1152/jappl.1998.85.5.1989.
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During recent years it has been suggested that forced expiratory measurements, derived from a lung volume set by a standardized inflation pressure, are more reproducible than those attained during tidal breathing when the rapid thoracoabdominal compression technique is used in infants. The aim of this study was to evaluate the feasibility of obtaining measurements from raised lung volumes in unsedated preterm infants. Measurements were made in 18 infants (gestational age 26–35 wk, postnatal age 1–10 wk, test weight 1.4–3.5 kg). Several inflations [1.5–2.5 kPa (15–25 cmH2O)] were used to briefly inhibit respiratory effort before the rapid thoracoabdominal compression was performed. Conventional analysis of flows and volumes at fixed times and percentages of the forced expiration resulted in a relatively high variability in this population. However, by using the elastic equilibrium point (i.e., the passively determined lung volume, derived from passive expirations before the forced expiration) as a volume landmark, it was feasible to achieve reproducible results in unsedated preterm infants, despite their strong respiratory reflexes and rapid respiratory rates. Because this approach is independent of changes in expiratory time, expired volume, or applied pressures, it may facilitate investigation of the effects of growth, development, and disease on airway function in infants, particularly during the first weeks of life, when conventional analysis of forced expirations may be inappropriate.
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van Hengstum, M., J. Festen, C. Beurskens, M. Hankel, F. Beekman, and F. Corstens. "Effect of positive expiratory pressure mask physiotherapy (PEP) versus forced expiration technique (FET/PD) on regional lung clearance in chronic bronchitics." European Respiratory Journal 4, no. 6 (1991): 651–54. http://dx.doi.org/10.1183/09031936.93.04060651.
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On theoretical grounds it is assumed that positive expiratory pressure mask physiotherapy (PEP) as a means of promoting mucus clearance is especially effective in the more distal airways. In a randomized cross-over trial including a control measurement the effect of PEP and of the forced expiration technique combined with postural drainage (FET/PD) on regional lung clearance was evaluated in seven patients with chronic bronchitis and abundant sputum production (mean 32 g.day-1). PEP consisted of positive expiratory pressure mask breathing interspersed with breathing exercises, forced expiration manoeuvres (huffing) and, if necessary, coughing. FET consisted of breathing exercises, huffing and also, if necessary, coughing. FET was combined with PD. Following inhalation of a radio-aerosol regional lung clearance was estimated by means of gamma camera imaging. The results after PEP appeared to be not significantly different from control. The mean clearance in all three lung zones (peripheral, intermediate and inner) was largest after FET/PD as compared with PEP and control. Statistical significance (p less than 0.02) was reached only for clearance in the inner region. It is concluded that PEP has no demonstrable effect on regional lung clearance in these patients.
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Peslin, R., J. Felicio da Silva, C. Duvivier, and F. Chabot. "Respiratory mechanics studied by forced oscillations during artificial ventilation." European Respiratory Journal 6, no. 6 (1993): 772–84. http://dx.doi.org/10.1183/09031936.93.06060772.
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Potential advantages of the forced oscillation technique over other methods for monitoring total respiratory mechanics during artificial ventilation are that it does not require patient relaxation, and that additional information may be derived from the frequency dependence of the real (Re) and imaginary (Im) parts of respiratory impedance. We wanted to assess feasibility and usefulness of the forced oscillation technique in this setting and therefore used the approach in 17 intubated patients, mechanically ventilated for acute respiratory failure. Sinusoidal pressure oscillations at 5, 10 and 20 Hz were applied at the airway opening, using a specially devised loudspeaker-type generator placed in parallel with the ventilator. Real and imaginary parts were corrected for the flow-dependent impedance of the endotracheal tube; they usually exhibited large variations during the respiratory cycle, and were computed separately for the inspiratory and expiratory phases. In many instances the real part was larger during inspiration, probably due to the larger respiratory flow, and decreased with increasing frequency. The imaginary part of respiratory impedance usually increased with increasing frequency during expiration, as expected for a predominately elastic system, but often varied little, or even decreased, with increasing frequency during inspiration. In most patients, the data were inconsistent with the usual resistance-inertance-compliance model. A much better fit was obtained with a model featuring central airways and a peripheral pathway in parallel with bronchial compliance. The results obtained with the latter model suggest that dynamic airway compression occurred during passive expiration in a number of patients. We conclude that the use of forced oscillation is relatively easy to implement during mechanical ventilation, that it allows the study of respiratory mechanics at various points in the respiratory cycle, and may help in detecting expiratory flow limitation.
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Alqahtani, Jaber S., Ahmad M. Al Rajeh, Abdulelah M. Aldhahir, Yousef S. Aldabayan, John R. Hurst, and Swapna Mandal. "The clinical utility of forced oscillation technique during hospitalisation in patients with exacerbation of COPD." ERJ Open Research 7, no. 4 (2021): 00448–2021. http://dx.doi.org/10.1183/23120541.00448-2021.
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BackgroundForced Oscillation Technique (FOT) is an innovative tool to measure within-breath reactance at 5 Hz (ΔXrs5Hz) but its feasibility and utility in acute exacerbations of COPD (AECOPD) is understudied.MethodsA prospective observational study was conducted in 82 COPD patients admitted due to AECOPD. FOT indices were measured and the association between these indices and spirometry, peak inspiratory flow rate, blood inflammatory biomarkers and patient-reported outcomes including assessment of dyspnoea, quality of life, anxiety and depression and frailty at admission and discharge were explored.ResultsAll patients were able to perform FOT in both sitting and supine position. The prevalence of expiratory flow limitation (EFL) in the upright position was 39% (32 out of 82) and increased to 50% (41 out of 82) in the supine position. EFL (measured by ΔXrs5Hz) and resistance at 5 Hz (Rrs5Hz) negatively correlated with forced expiratory volume in 1 s (FEV1); those with EFL had lower FEV1 (0.74±0.30 versus 0.94±0.36 L, p = 0.01) and forced vital capacity (1.7±0.55 versus 2.1±0.63 L, p = 0.009) and higher body mass index (27 (21–36) versus 23 (19–26) kg·m−2, p = 0.03) compared to those without EFL. During recovery from AECOPD, changes in EFL were observed in association with improvement in breathlessness.ConclusionFOT was easily used to detect EFL during hospitalisation due to AECOPD. The prevalence of EFL increased when patients moved from a seated to a supine position and EFL was negatively correlated with airflow limitation. Improvements in EFL were associated with a reduction in breathlessness. FOT is of potential clinical value by providing a noninvasive, objective and effort-independent technique to measure lung function parameters during AECOPD requiring hospital admission.
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Hao, Weihong, Chunmin Zhang, Jiandong He, Ruomeng Pei, Haiyan Huo, and Huihui Liu. "Effect of ultrasound-guided nerve blocks on anesthesia and pulmonary function in patients undergoing distal radius fracture surgery." Medicine 103, no. 35 (2024): e39436. http://dx.doi.org/10.1097/md.0000000000039436.
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This study aimed to assess the impact of ultrasound (US)-guided nerve blocks (NBs) on anesthesia and their protective effect on pulmonary function (PF) in patients undergoing distal radius fracture (DRF) surgery. A total of 122 patients undergoing DRF surgery between April 2020 and June 2023 were included. According to the type of peripheral NB technique, these patients were randomized into a control group (CG; n = 60) receiving brachial plexus block (BPB) using blinded techniques, and an observation group (OG; n = 62) receiving US-guided supraclavicular BPB. Anesthetic effects, BPB-related indexes, adverse events, PF parameters (forced expiratory volume in 1 second, forced vital capacity, peak expiratory flow), and serum biochemical indexes (interleukin [IL]-6/10) were compared. The OG showed a relatively higher proportion of good anesthetic effects, shorter onset and completion times of block, and longer block duration compared to the CG, with a lower AE rate. Despite reductions in PF parameters and IL-10 levels after intervention, the OG maintained higher values than the CG. IL-6 levels increased significantly in the OG but remained lower than in the CG. In conclusion, US-guided NBs demonstrated significant anesthetic efficacy and apparently reduced anesthesia adverse events while also exerting a protective effect on PF in DRF surgery patients.
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Bridge, PD, H. Lee, and M. Silverman. "A portable device based on the interrupter technique to measure bronchodilator response in schoolchildren." European Respiratory Journal 9, no. 7 (1996): 1368–73. https://doi.org/10.1183/13993003/erj.9.7.1368.
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A new device for measuring airway resistance following brief airflow interruption (Microlab 4000; Micromedical Ltd, UK) was evaluated in 25 asthmatic school children in comparison with well-established methods. Airway resistance was measured during brief airflow interruption (Rint), before and after administration of salbutamol 200 micrograms by metered-dose inhaler, and in the spirometric parameters, forced expiratory volume in one second (FEV1) and peak expiratory flow (PEF), and total respiratory system resistance at 6 Hz (Rrs,6) measured by the forced oscillation technique (FOT). The sensitivity index (SI) (mean change/baseline standard deviation) was calculated for each subject. At baseline, interrupter conductance, the reciprocal of Rint, correlated well with FEV1 (r = 0.837; p < 0.001) and PEF (r = 0.773; p < 0.001), and Rint correlated highly with Rrs,6 (r = 0.942; p < 0.001). The median intrasubject coefficient of variation of the interrupter method was higher than the FOT or either spirometric parameter; Rint 11%, Rrs,6 9%, FEV1 5% and PEF 5%. However, the sensitivity to detect change after bronchodilator, expressed as the median SI, did not differ significantly between measurements: Rint 3.5, Rrs,6 3.6, FEV1 2.4 and PEF 3.0. A significant response (SI > 2) was shown by the interrupter in 22 of the subjects compared with 16 by FEV1. The interrupter technique is useful for assessing changes in airway calibre in asthmatic school children, with a sensitivity at least as good as standard methods. Such a device could be of particular value in those too young to perform spirometry.
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Nathan C.V., Senthil, Kavitha Lakshmi J., Vaishnavi G., and Manoj Abraham M. "Effectiveness of swallowing therapy and forced expiratory technique to prevent aspiration for dysphagia in frail elders." Biomedicine 43, no. 4 (2023): 1315–19. http://dx.doi.org/10.51248/.v43i4.2355.
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Introduction and Aim: Difficulty or trouble in eating is termed to beDysphagia, which indicates experience of food encountering delays or obstructions as it moves to the stomach from the mouth. Elderly population is prone to develop dysphagia because of various illnesses that affect their swallowing function, thereby raising the threat of aspiration. The primary goal of the current learning is to assess the effectiveness of swallowing therapy and the forced expiratory technique as preventive measures against aspiration in frail elderly individuals with dysphagia. Methodology: This study is an experimental study done at ACS Medical College and Hospital, specifically in the Physiotherapy OP department. The study involved a sample of 20 individuals and had a treatment duration of 6 weeks. The participants were elderly individuals ranging from 65 to 85 years of age, comprising both males and females. Participants who scored above 18 in the mini mental state exam and fall within levels 3 to 6 according to the FIOS classification were included The outcome measures used in the study were the functional intake oral scale and the gugging swallowing screen. Results: Comparing the Functional Intake Oral Scale (FIOS) Score between the Pre-test and Post-test mean values of 4.40 and 6.40 (Swallowing Therapy) reveals a significantly significant difference between the two mean values at P 0.001. Comparing the gugging swallowing screen (GUSS)score between the Pre-test and Post-test mean values of 11.30 and 17.60 (Swallowing Therapy), it is very significant that there is a difference between the Pre-test and Post-test mean values at P 0.001. Conclusion: It is concluded that there is significant improvement in effects of swallowing therapy for dysphagia in frail elders and forced expiratory technique to prevent aspiration.
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Van Hengstum, M., J. Festen, C. Beurskens, et al. "The Effect of Positive Expiratory Pressure versus Forced Expiration Technique on Tracheobronchial Clearance in Chronic Bronchitics." Scandinavian Journal of Gastroenterology 23, sup143 (1988): 114–18. http://dx.doi.org/10.3109/00365528809090229.
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Dellaca, R. L. "Assessing respiratory mechanics in obstructive diseases by forced oscillation technique: importance of expiratory flow-limitation (EFL)." Journal of Biomechanics 39 (January 2006): S597. http://dx.doi.org/10.1016/s0021-9290(06)85478-3.
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Watts, Joanna C., Claude S. Farah, Leigh M. Seccombe, et al. "Measurement duration impacts variability but not impedance measured by the forced oscillation technique in healthy, asthma and COPD subjects." ERJ Open Research 2, no. 2 (2016): 00094–2015. http://dx.doi.org/10.1183/23120541.00094-2015.
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The forced oscillation technique (FOT) is gaining clinical acceptance, facilitated by more commercial devices and clinical data. However, the effects of variations in testing protocols used in FOT data acquisition are unknown. We describe the effect of duration of data acquisition on FOT results in subjects with asthma, chronic obstructive pulmonary disease (COPD) and healthy controls.FOT data were acquired from 20 healthy, 22 asthmatic and 18 COPD subjects for 60 s in triplicate. The first 16, 30 and 60 s of each measurement were analysed to obtain total, inspiratory and expiratory resistance of respiratory system (Rrs) and respiratory system reactance (Xrs) at 5 and 19 Hz.With increasing duration, there was a decrease in total and expiratory Rrs for healthy controls, total and inspiratory Rrs for asthmatic subjects and magnitude of total and inspiratory Xrs for COPD subjects at 5 Hz. These decreases were small compared to the differences between clinical groups. Measuring for 16, 30 and 60 s provided ≥3 acceptable breaths in at least 90, 95 and 100% of subjects, respectively. The coefficient of variation for total Rrs and Xrs also decreased with duration. Similar results were found for Rrs and Xrs at 19 Hz.FOT results are statistically, but likely minimally, impacted by acquisition duration in healthy, asthmatic or COPD subjects.
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Welch, Ryan, Alaina Francis, Thalia Babbage, Mandy Lardenoye, John Kolbe, and Kevin Ellyett. "Quantifying tidal expiratory flow limitation using a vector-based analysis technique." Physiological Measurement 42, no. 11 (2021): 115003. http://dx.doi.org/10.1088/1361-6579/ac3f96.
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Abstract Objective. Tidal expiratory flow limitation (EFLT) is commonly identified by tidal breaths exceeding the forced vital capacity (FVC) loop. This technique, known as the Hyatt method, is limited by the difficulties in defining the FVC and tidal flow-volume (TV) loops. The vector-based analysis (VBA) technique described and piloted in this manuscript identifies and quantifies EFLT as tidal breaths that conform to the contour of the FVC loop. Approach. The FVC and TV loops are interpolated to generate uniformly spaced plots. VBA is performed to determine the smallest vector difference between each point on the FVC and TV curves, termed the flow reserve vector (FRV). From the FVC point yielding the lowest FRV, the tangential angles of the FVC and TV segments are recorded. If the TV and FVC loops become parallel, the difference between the tangential angles tends towards zero. We infer EFLT as parallel TV and FVC segments where the FRV is < 0.1 and the tangential angle is within ±18 degrees for ≥5% of TV. EFLT is quantified by the percent of TV loop fulfilling these criteria. We compared the presence and degree of EFLT at rest and during peak exercise using the Hyatt method and our VBA technique in 25 healthy subjects and 20 subjects with moderate-severe airflow obstruction. Main results. Compared to the Hyatt method, our VBA technique reported a significantly lower degree of EFLT in healthy subjects during peak exercise, and in obstructed subjects at rest and during peak exercise. In contrast to the Hyatt method, our VBA technique re-classified five subjects (one in the healthy group and four in the obstructed group) as demonstrating EFLT. Significance. Our VBA technique provides an alternative approach to determine and quantify EFLT which may reduce the overestimation of the degree EFLT and more accurately identify subjects experiencing EFLT.
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Xu, Hui, Yi Gao, Yanqing Xie, Xiaolin Liang, and Jinping Zheng. "Bronchial provocation test measured by using the forced oscillation technique to assess airway responsiveness." Allergy and Asthma Proceedings 42, no. 5 (2021): e127-e134. http://dx.doi.org/10.2500/aap.2021.42.210044.
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Background: The bronchial provocation test (BPT) performed by using the forced oscillation technique (FOT) is cooperated without forced expiratory effort. However, a comparison of the application value and safety of BPTs measured by using the FOT and the standardized dosimeter method is lacking, which limits its clinical practice. Objective: We aimed to analyze the diagnostic value and safety of the BPT as measured by the FOT in patients with asthma and in healthy subjects. Methods: This was a randomized cross-over clinical study. Airway responsiveness was measured by using the FOT and the aerosol provocation system (APS) dosimeter method in all the participants. The between-test interval was 24 hours. The diagnostic value and safety of the two tests were analyzed. Results: Asthma control status was assessed based on ACT scores, and patients with asthma (including 27 uncontrolled, 34 partially controlled, and 32 controlled) were collected, and 69 healthy subjects were recruited. Receiver operating characteristic curves revealed slightly superior screening capability of cumulative dose of methacholine causing a 20% decrease (PD20)‐forced expiratory volume in the first second of expiration when measured by using the APS-dosimeter method (area under the curve [AUC] 0.981 [95% confidence interval {CI}, 0.952‐1.000]) over that of cumulative dose of inhaled methacholine at the inflection point when respiratory resistance began to increase continuously (Dmin) by using the FOT (AUC 0.959 [95% CI, 0.924‐0.994]). The sensitivity and specificity were 98.9% and 98.6%, respectively, with the APS-dosimeter method, and 100% and 87.0%, respectively, with the FOT. It took an average of 9.0 minutes (range, 6.0‐11.0 minutes) when using the FOT and an average of 17.0 minutes (range, 14.0‐25.0 minutes) when using APS-dosimeter method (p < 0.01) in all the participants. The measurement time for the FOT was reduced by 47.1% than the APS-dosimeter. The incidence rate of the adverse events with the FOT was slightly higher than that with the APS-dosimeter method (p < 0.05). Both tests were well tolerated. No serious adverse event was found. Conclusion: The FOT, characterized as being simple, safe, and time saving, could be used to assess airway hyperresponsiveness in patients with asthma and worthy of clinical application.
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Lorino, AM, F. Lofaso, F. Abi-Nader, et al. "Nasal airflow resistance measurement: forced oscillation technique versus posterior rhinomanometry." European Respiratory Journal 11, no. 3 (1998): 720–25. http://dx.doi.org/10.1183/09031936.98.11030720.
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This study was designed to determine whether nasal airflow resistance (Rn) which is nonlinear during tidal breathing, can be assessed by the forced oscillation (FO) technique. Rn values obtained by the FO technique and extrapolated to 0 Hz (Rn,FO) were compared to those assessed by posterior rhinomanometry at maximal tidal inspiratory flow (Rn,m), at a 0.5 L x s(-1) flow (Rn,F), and at a 1 hPa transnasal pressure (Rn,P). All Rn estimates were derived from the same inspiratory and expiratory nasal flow and transnasal pressure signals obtained during tidal nasal breathing whilst a forced flow was applied at the nose via a rigid nasal mask in 23 healthy volunteers, of whom 14 had additional measurements after vasoconstrictor treatment. In the basal state, no significant difference, and significant correlations (p<0.0001) were found between Rn,FO and the other Rn estimates. Only the regression line of Rn,FO versus Rn,m was not significantly different from the identity line. After nasal decongestion, Rn,P became significantly higher than the other Rn estimates (p<0.005). The regression line of Rn,FO versus Rn,m remained nonsignificantly different from the identity line. Similar results were observed regarding the percentage values of the different Rn estimates after decongestant treatment. This study shows that, despite its nonlinearity, Rn can be assessed by the FO technique, and that Rn,FO and Rn,m could be indifferently used as physiological indices of nasal patency. As the FO technique is more difficult to implement than the conventional rhinomanometry, its interest in rhinology appears not to be obvious.
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Milic-Emili, Joseph, Luigi Marazzini, and Edgardo D’Angelo. "150 Years of Blowing: Since John Hutchinson." Canadian Respiratory Journal 4, no. 5 (1997): 239–45. http://dx.doi.org/10.1155/1997/321329.
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Three recent advances in assessment of routine lung function are reviewed. In both normal subjects and patients with obstructive lung disease, the flows during the forced vital capacity (FVC) manoeuvre depend significantly on the pattern of the preceding inspiratory manoeuvre. Accordingly, the latter should be standardized in clinical and epidemiological studies. Although the nature of this phenomenon is not fully understood, stress relaxation of lung tissues probably plays the primary role. The negative expiratory pressure technique provides a simple and reliable tool for detecting expiratory flow limitation both at rest and during exercise. The method does not require body plethysmography or the patient’s cooperation and coordination, and can be applied in any desired body posture. A simple method for monitoring FVC performance has been developed. It allows detection of flow limitation during the FVC manoeuvre.
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Suh, Eui-Sik, Pasquale Pompilio, Swapna Mandal, et al. "Autotitrating external positive end-expiratory airway pressure to abolish expiratory flow limitation during tidal breathing in patients with severe COPD: a physiological study." European Respiratory Journal 56, no. 3 (2020): 1902234. http://dx.doi.org/10.1183/13993003.02234-2019.
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BackgroundThe optimal noninvasive application of external positive end-expiratory pressure (EPAP) to abolish tidal-breathing expiratory flow limitation (EFLT) and minimise intrinsic positive end-expiratory pressure (PEEPi) is challenging in COPD patients. We investigated whether auto-titrating EPAP, using the forced oscillation technique (FOT) to detect and abolish EFLT, would minimise PEEPi, work of breathing and neural respiratory drive (NRD) in patients with severe COPD.MethodsPatients with COPD with chronic respiratory failure underwent auto-titration of EPAP using a FOT-based algorithm that detected EFLT. Once optimal EPAP was identified, manual titration was performed to assess NRD (using diaphragm and parasternal intercostal muscle electromyography, EMGdi and EMGpara, respectively), transdiaphragmatic inspiratory pressure swings (ΔPdi), transdiaphragmatic pressure–time product (PTPdi) and PEEPi, between EPAP levels 2 cmH2O below to 3 cmH2O above optimal EPAP.ResultsOf 10 patients enrolled (age 65±6 years; male 60%; body mass index 27.6±7.2 kg.m−2; forced expiratory volume in 1 s 28.4±8.3% predicted), eight had EFLT, and optimal EPAP was 9 (range 4–13) cmH2O. NRD was reduced from baseline EPAP at 1 cmH2O below optimal EPAP on EMGdi and at optimal EPAP on EMGpara. In addition, at optimal EPAP, PEEPi (0.80±1.27 cmH2O versus 1.95± 1.70 cmH2O; p<0.05) was reduced compared with baseline. PTPdi (10.3±7.8 cmH2O·s−1versus 16.8±8.8 cmH2O·s−1; p<0.05) and ΔPdi (12.4±7.8 cmH2O versus 18.2±5.1 cmH2O; p<0.05) were reduced at optimal EPAP+1 cmH2O compared with baseline.ConclusionAutotitration of EPAP, using a FOT-based algorithm to abolish EFLT, minimises transdiaphragmatic pressure swings and NRD in patients with COPD and chronic respiratory failure.
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An, Ho Jung, and Shin Jun Park. "Effects of Cervical Spine Mobilization on Respiratory Function and Cervical Angles of Stroke Patients: A Pilot Study." Healthcare 9, no. 4 (2021): 377. http://dx.doi.org/10.3390/healthcare9040377.
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The forward head posture (FHP) of stroke patients has a negative impact on respiratory function. Cervical spine mobilization is a manual therapy technique that used to prevent and treat FHP and respiratory function. This pilot study investigated whether cervical spine mobilization can effectively improve outcomes following FHP and respiratory function of stroke patients. Twenty-four patients participated in our assessor-blinded randomized controlled trial. All the participants received neurodevelopmental treatments (gait training and trunk rehabilitation). The experimental group additionally received 15-min sessions of cervical spine mobilization three times per week for 4 weeks. The control group received cervical spine sham mobilization during the same period. For the cervical angles, the cranial vertebral angle (CVA) and cranial rotation angle (CRA) were measured. A respiratory function test was performed to measure the forced vital capacity (FVC), forced expiratory volume in 1 s (FEV1), peak expiratory flow (PEF), maximal inspiratory pressure (MIP), maximal expiratory pressure (MEP), and chest circumferences (upper and lower chest sizes). Except for MIP, there was no significant difference between the experimental group and the control group. The CVA and CRA were significantly increased in the experimental group only. Cervical spine mobilization improved cervical angles and inspiratory function of the stroke patients in this study. However, a comparative study with a larger number of patients is needed to confirm this finding from our pilot study, which had a small sample size.
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Tichopád, Aleš, Jan Žigmond, Miloš Jeseňák, et al. "Adherence to application technique of inhaled corticosteroid in patients with asthma and COVID-19 improves outcomes." BMJ Open Respiratory Research 11, no. 1 (2024): e001874. http://dx.doi.org/10.1136/bmjresp-2023-001874.
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BackgroundInhaled corticosteroids have been widely reported as a preventive measure against the development of severe forms of COVID-19 not only in patients with asthma.MethodsIn 654 Czech and Slovak patients with asthma who developed COVID-19, we investigated whether the correct use of inhaler containing corticosteroids was associated with a less severe course of COVID-19 and whether this had an impact on the need for hospitalisation, measurable lung functions and quality of life (QoL).ResultsOf the studied cohort 51.4% had moderate persistent, 29.9% mild persistent and 7.2% severe persistent asthma. We found a significant adverse effect of poor inhaler adherence on COVID-19 severity (p=0.049). We also observed a lower hospitalisation rate in patients adequately taking the inhaler with OR of 0.83. Vital capacity and forced expiratory lung volume deterioration caused by COVID-19 were significantly reversed, by approximately twofold to threefold, in individuals who inhaled correctly.ConclusionHigher quality of inhalation technique of corticosteroids measured by adherence to an inhaled medication application technique (A-AppIT) score had a significant positive effect on reversal of the vital capacity and forced expiratory lung volume in 1 s worsening (p=0.027 and p<0.0001, respectively) due to COVID-19. Scoring higher in the A-AppIT was also associated with significantly improved QoL. All measured variables concordantly and without exception showed a positive improvement in response to better adherence. We suggest that corticosteroids provide protection against the worsening of lungs in patients with COVID-19 and that correct and easily assessable adherence to corticosteroids with appropriate inhalation technique play an important role in preventing severe form of COVID-19.
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Merkus, PJ, S. Verver, EE van Essen-Zandvliet, EJ Duiverman, KF Kerrebijn, and PH Quanjer. "Lung volumes measured by the forced rebreathing technique in children with airways obstruction." European Respiratory Journal 5, no. 7 (1992): 879–86. http://dx.doi.org/10.1183/09031936.93.05070879.
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Forced rebreathings may recruit trapped gas into the mixing process. Therefore, we assessed the validity and reproducibility of measurements of residual volume (RVN2) by forced rebreathing in a closed circuit using N2 as indicator gas (N2FR) in children with airways obstruction. Validity was studied from measurements of RV obtained by N2FR, by helium dilution during resting ventilation, and by body plethysmograph at low panting frequency in young patients (8-18 yrs, 13 with asthma, forced expiratory volume in one second (FEV1) 93.0 +/- 22.8% pred; 12 with cystic fibrosis (CF), FEV1 80.4 +/- 16.4% pred). Reproducibility of RVN2 was assessed from duplicate measurements in 73 patients with asthma before and after bronchodilation (FEV1 81.4 +/- 13.7 and 99.6 +/- 11.5% pred, respectively), and in nine patients with CF; the total lung capacity (TLC) was unaffected by bronchodilation; 3,797 +/- 830 ml and 3,807 +/- 843 ml, respectively. Gas dilution methods gave comparable results in all subjects but gave lower values than plethysmography in patients with cystic fibrosis. Reproducibility was satisfactory, median differences between duplicate measurements of RVN2 and TLCN2 varying between 13 and 46 ml, respectively. We conclude that N2FR is quickly performed and well-tolerated. Lung volumes are highly reproducible and agree well with those obtained with the helium dilution method. Deep inspirations do not seem to overcome gas trapping in patients with CF.
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Ishii, Mitsuaki. "Benefit of Forced Expiratory Technique for Weak Cough in a Patient with Bulbar Onset Amyotrophic Lateral Sclerosis." Journal of Physical Therapy Science 16, no. 2 (2004): 137–41. http://dx.doi.org/10.1589/jpts.16.137.
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Maierean, Anca, Teodora Gabriela Alexescu, Lorena Ciumarnean, et al. "Non Cystic Fibrosis Bronchiectasis-new clinical approach, management of treatment and pulmonary rehabilitation." Balneo Research Journal 10, no. 10.2 (2019): 103–13. http://dx.doi.org/10.12680/balneo.2019.247.
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Abstract Non-Cystic Fibrosis Bronchiectasis (NCFB) are characterised by abnormal, permanently damaged and dilated bronchi due to the innapropiate clearence of various microorganisms and recurrent chronic infections.The diagnosis is suggested by the clinical presentation and is confirmed by multiple investigations. There are some comorbidities associated with bronhciectasis, such as chronic obstructive pulmonary disease (COPD), cardiovascular disorders, gastro-esophageal reflux disease (GERD), psychological illnesses, pulmonary hypertension, obstructive apnea syndrome(OSA). The condition has a substantial socioeconomic impact because it requests a multidisciplinary management and periods of exacerbations are common. The aims of the management of bronchiectasis are to reduce symptoms (such as sputum volume and purulence, cough and dyspnea), reduce the frequency and severity of exacerbations, preserve lung function and improve health-related quality of life. The multidisciplinary approach of bronchiectasis patients require along with the medical treatment, a specific plan of nonphamarcological strategies, including balneological intervention. There are a lot of techniques improving the airway clearence, such as: active cycle of breathing techniques (which include breathing control, thoracic expansion exercises, forced expiratory technique), oscilatting possitive expiratory pressure, autogenic drainage, gravity-assisted-positioning, modified postural drainage. Together with specific medication, these techniques can diminuate symptoms and improve the quality of life. Key words: NCFB, airway clearence, physiotherapy,
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Poncin, William, Christine Schrøder, Ana Oliveira, et al. "Airway clearance techniques for people with acute exacerbation of COPD: a scoping review." European Respiratory Review 34, no. 175 (2025): 240191. https://doi.org/10.1183/16000617.0191-2024.
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IntroductionAcute exacerbations of COPD (AECOPD) often involve mucus hypersecretion. Thus, management of sputum retention is critical. However, the use of airway clearance techniques (ACTs) in people with AECOPD across different healthcare settings and factors influencing their selection remain unclear.ObjectiveTo identify and map ACTs used for AECOPD in different healthcare settings and the factors influencing clinical decision-making worldwide.MethodsFour electronic databases and grey literature were searched from 1995 to December 2023, with hand-searching of eligible records. The Joanna Briggs Institute methodology for scoping reviews was followed.Results25 articles were included: 14 clinical studies, five guidelines/statements and six surveys/audits. Clinical studies reported the use of a wide range of single or combined ACTs, with no clear pattern in using particular ACTs in different parts of the world. Recent guidelines advise using ACTs for certain patients with AECOPD, particularly those with hypersecretion, with most guidelines recommending positive expiratory pressure (PEP) therapy. According to surveys, the most used ACTs in Australia and Europe are active cycle of breathing techniques, PEP or forced expiratory technique, while vibrations are most frequently used in Canada. Factors influencing the selection of specific ACTs include the presence of contraindications, level of dyspnoea, access to resources/equipment and ease of learning/performing the technique. All information was derived from hospital settings.ConclusionsThis scoping review identified and mapped ACTs used for people with AECOPD worldwide and their decision-making factors. Future work should focus on community settings.
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Vogt, Barbara, Zhanqi Zhao, Peter Zabel, Norbert Weiler, and Inéz Frerichs. "Regional lung response to bronchodilator reversibility testing determined by electrical impedance tomography in chronic obstructive pulmonary disease." American Journal of Physiology-Lung Cellular and Molecular Physiology 311, no. 1 (2016): L8—L19. http://dx.doi.org/10.1152/ajplung.00463.2015.
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Patients with obstructive lung diseases commonly undergo bronchodilator reversibility testing during examination of their pulmonary function by spirometry. A positive response is defined by an increase in forced expiratory volume in 1 s (FEV1). FEV1 is a rather nonspecific criterion not allowing the regional effects of bronchodilator to be assessed. We employed the imaging technique of electrical impedance tomography (EIT) to visualize the spatial and temporal ventilation distribution in 35 patients with chronic obstructive pulmonary disease at baseline and 5, 10, and 20 min after bronchodilator inhalation. EIT scanning was performed during tidal breathing and forced full expiration maneuver in parallel with spirometry. Ventilation distribution was determined by EIT by calculating the image pixel values of FEV1, forced vital capacity (FVC), tidal volume, peak flow, and mean forced expiratory flow between 25 and 75% of FVC. The global inhomogeneity indexes of each measure and histograms of pixel FEV1/FVC values were then determined to assess the bronchodilator effect on spatial ventilation distribution. Temporal ventilation distribution was analyzed from pixel values of times needed to exhale 75 and 90% of pixel FVC. Based on spirometric FEV1, significant bronchodilator response was found in 17 patients. These patients exhibited higher postbronchodilator values of all regional EIT-derived lung function measures in contrast to nonresponders. Ventilation distribution was inhomogeneous in both groups. Significant improvements were noted for spatial distribution of pixel FEV1 and tidal volume and temporal distribution in responders. By providing regional data, EIT might increase the diagnostic and prognostic information derived from reversibility testing.
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Darbee, Joan C., Patricia J. Ohtake, Brydon JB Grant, and Frank J. Cerny. "Physiologic Evidence for the Efficacy of Positive Expiratory Pressure as an Airway Clearance Technique in Patients With Cystic Fibrosis." Physical Therapy 84, no. 6 (2004): 524–37. http://dx.doi.org/10.1093/ptj/84.6.524.
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Abstract Background and Purpose. Individuals with cystic fibrosis (CF) have large amounts of infected mucus in their lungs, which causes irreversible lung tissue damage. Although patient-administered positive expiratory pressure (PEP) breathing has been promoted as an effective therapeutic modality for removing mucus and improving ventilation distribution in these patients, the effects of PEP on ventilation distribution and gas mixing have not been documented. Therefore, this preliminary investigation described responses in distribution of ventilation and gas mixing to PEP breathing for patients with moderate to severe CF lung disease. Subjects and Methods. The effects of PEP breathing on ventilation distribution, gas mixing, lung volumes, expiratory airflow, percentage of arterial blood oxyhemoglobin saturation (Spo2), and sputum volume were studied in 5 patients with CF (mean age=18 years, SD=4, range=13–22) after no-PEP, low-PEP (10–20 cm H2O), and high-PEP (&gt;20 cm H2O) breathing conditions. Single-breath inert gas studies and lung function tests were performed before, immediately after, and 45 minutes after intervention. Single-breath tests assess ventilation distribution homogeneity and gas mixing by observing the extent to which an inspired test gas mixes with gas already residing in the lung. Results. Improvements in gas mixing were observed in all PEP conditions. By 45 minutes after intervention, the no-PEP group improved by 5%, the low-PEP group improved by 15%, and the high-PEP group improved by 23%. Slow vital capacity increased by 1% for no PEP, by 9% for low PEP, and by 13% for high PEP 45 minutes after intervention. Residual volume decreased by 13% after no PEP, by 20% after low PEP, and by 30% after high PEP. Immediate improvements in forced expiratory flow during the middle half of the forced vital capacity maneuver (FEF25%–75%) were sustained following high PEP but not following low PEP. Discussion and Conclusion. This study demonstrated the physiologic basis for the efficacy of PEP therapy. The results confirm that low PEP and high PEP improve gas mixing in individuals with CF, and these improvements were associated with increased lung function, sputum expectoration, and SpO2. The authors propose that improvements in gas mixing may lead to increases in oxygenation and thus functional exercise capacity.
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van Hengstum, M., J. Festen, C. Beurskens, M. Hankel, W. van den Broek, and F. Corstens. "No effect of oral high frequency oscillation combined with forced expiration manoeuvres on tracheobronchial clearance in chronic bronchitis." European Respiratory Journal 3, no. 1 (1990): 14–18. http://dx.doi.org/10.1183/09031936.93.03010014.
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This study compared the effect of oral high frequency oscillation (OHFO) with the effect of the forced expiration technique (FET) on tracheobronchial clearance. Eight patients with chronic bronchitis were investigated (mean age 60 +/- 10 yrs, mean forced expiratory volume in one second (FEV1) 68 +/- 27% predicted, mean sputum production 33 +/- 9 g.day-1). OHFO was applied at the respiratory system resonant frequency of each patient (range 9.2-25 Hz) and combined with huffing. FET included breathing exercises, huffing and postural drainage. Duration of both OHFO and FET was 30 minutes. Tracheobronchial clearance was measured by means of a radio-aerosol technique. At 60 mins after start of the treatment mean tracheobronchial retention was 70 +/- 26% after OHFO, 54 +/- 26% after FET and 76 +/- 18% in the control run, which included huffing only. OHFO was not significantly different from control. FET was significantly different (p less than 0.02) from both OHFO and control. It is concluded that OHFO has no effect on tracheobronchial clearance in chronic bronchitis.
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Coe, C. I., A. Watson, H. Joyce, and N. B. Pride. "Effects of smoking on changes in respiratory resistance with increasing age." Clinical Science 76, no. 5 (1989): 487–94. http://dx.doi.org/10.1042/cs0760487.
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1. The oscillation method for measuring total respiratory resistance (Rrs) is a simple method of assessing airway dimensions which can be applied in epidemiological surveys and potentially might be useful for detecting mild airway disease in smokers. However, it is not known whether abnormalities in Rrs are only present when there are also abnormalities in simple spirometric tests. 2. We have compared values of Rrs and its frequency-dependence (fR) using the oscillation technique applied over the frequency range 6-26 Hz in 42 healthy, non-asthmatic men who were never-smokers (aged 26-61 years) and in 41 male cigarette smokers (aged 32-64 years). The results were compared with those for spirometry and the single-breath N2 test which are the most commonly used techniques in epidemiological surveys for detecting the effects of smoking on the lungs. 3. There was a strong trend for Rrs (especially at lower oscillation frequency) and fR to increase with increasing age in smokers. Increases in Rrs and fR were usually present when forced expiratory volume in 1 s was less than 80% of predicted and the forced expiratory volume in 1 s/vital capacity ratio was less than 65%, but abnormal fR was present in some smokers whose spirometry was within conventional normal limits. 4. Abnormalities in Rrs and fR were weakly associated with abnormality of the single-breath N2 manoeuvre. 5. Abnormal fR is normally attributed to uneven narrowing of intrathoracic airways; however, in smokers it was associated with an increase in Rrs at 6 Hz, so we cannot exclude that some of the observed abnormal fR was due to increased dissipation of the applied pressure in the cheeks and extrathoracic airway rather than to in-homogeneities within the lungs. 6. We conclude that the oscillation technique detects abnormalities indicating airway narrowing in some smokers whose spirometry is within normal limits. Hence the technique could be useful in screening programmes aiming to detect early lung damage. The prognostic significance of the additional information provided by measuring Rrs needs to be further assessed.
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McNamara, J. J., R. G. Castile, M. S. Ludwig, G. M. Glass, R. H. Ingram, and J. J. Fredberg. "Heterogeneous regional behavior during forced expiration before and after histamine inhalation in dogs." Journal of Applied Physiology 76, no. 1 (1994): 356–60. http://dx.doi.org/10.1152/jappl.1994.76.1.356.
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We studied the evolution of alveolar pressure (PA) heterogeneity during the course of forced expiration in the lungs of six anesthetized open-chest dogs. Using an alveolar capsule technique, we measured PA simultaneously in six lung regions during full maximal forced deflations before and after administering aerosolized histamine. Flow was measured plethysmographically with volume obtained by flow integration. Heterogeneity was expressed as the coefficient of variation (CV) of regional PA after 25% of the vital capacity had been expired from total lung capacity. The CV in in vivo open-chest canine lungs (21.3%) was significantly greater than that we measured previously in excised lungs (8.7%) (P < 0.02). Inhalation of aerosolized solutions of histamine produced significant increases in interregional heterogeneity (CV = 35.5 and 38.8% after 3 and 10 mg/ml of histamine, respectively; P < 0.025). After histamine, the vital capacity was reduced and the configuration of the flow-volume curve demonstrated some shortening of the flow plateau commonly observed in dogs. Changes in the flow-volume relationship failed, however, to reflect well the marked degree of heterogeneity of PA after histamine administration. These findings may be reconciled on the basis of interdependence of regional expiratory flows. Reductions in flow from obstructed regions appear to be compensated by increases in flow from unobstructed regions and thus mask upstream nonuniformities. These mechanisms may explain in part why the maximal expiratory flow-volume curve has been a relatively insensitive tool for the detection of early nonuniform airway disease.
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Tan, Jason K., Georgia Banton, Corrado Minutillo, et al. "Long-term medical and psychosocial outcomes in congenital diaphragmatic hernia survivors." Archives of Disease in Childhood 104, no. 8 (2019): 761–67. http://dx.doi.org/10.1136/archdischild-2018-316091.
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ObjectiveSurvival rates for congenital diaphragmatic hernia (CDH) are increasing. The long-term outcomes of CDH survivors were compared with a healthy control group to assess the morbidity for guidance of antenatal counselling and long-term follow-up programmes.Participants and designParticipants born with CDH in Western Australia 1993–2008 were eligible with matched controls from the general population. Participants had comprehensive lung function tests, echocardiogram, low-dose chest CT scan and completed a Strengths and Difficulties Questionnaire (SDQ) and quality of life (QOL) questionnaire.Results34 matched case–control pairs were recruited. Demographic data between groups were similar. Cases were smaller at follow-up (weight Z-score of −0.2vs0.3; p=0.03; height Z-score of −0.3vs0.6; p=0.01). Cases had lower mean Z-scores for forced expiratory volume in 1 s (FEV1) (−1.49 vs −0.01; p=0.004), FEV1/forced vital capacity (−1.92 vs −1.2; p=0.009) and forced expiratory flow at 25-75% (FEF25-75) (−1.18vs0.23; p=0.007). Cases had significantly worse respiratory mechanics using forced oscillation technique. Subpleural triangles architectural distortion, linear opacities and scoliosis on chest CT were significantly higher in cases. Prosthetic patch requirement was associated with worse lung mechanics and peak cough flow. Cases had significantly higher rates of gastro-oesophageal reflux disease (GORD) and GORD medication usage. Developmental delay was significantly higher in cases. More cases had a total difficulties score in the high to very high range (25% vs 0%, p=0.03) on the SDQ and reported lower objective QOL scores (70.2 vs 79.8, p=0.02).ConclusionSurvivors of CDH may have significant adverse long-term medical and psychosocial issues that would be better recognised and managed in a multidisciplinary clinic.
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Aarli, B. B., P. M. A. Calverley, T. M. L. Eagan, P. S. Bakke, and J. A. Hardie. "Exacerbation history in COPD patients with and without Expiratory Flow Limitation (EFL) measured by forced oscillometry technique (FOT)." Respiratory Medicine 107, no. 11 (2013): S6—S7. http://dx.doi.org/10.1016/j.rmed.2013.08.031.
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Bozanich, Elizabeth M., Rachel A. Collins, Cindy Thamrin, Zoltán Hantos, Peter D. Sly, and Debra J. Turner. "Developmental changes in airway and tissue mechanics in mice." Journal of Applied Physiology 99, no. 1 (2005): 108–13. http://dx.doi.org/10.1152/japplphysiol.01111.2004.
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Most studies using mice to model human lung diseases are carried out in adults, although there is emerging interest in the effects of allergen, bacterial, and viral exposure early in life. This study aims to characterize lung function in BALB/c mice from infancy (2 wk) through to adulthood (8 wk). The low-frequency forced oscillation technique was used to obtain impedance data, partitioned into components representing airway resistance, tissue damping, tissue elastance, and hysteresivity (tissue damping/tissue elastance). Measurements were made at end-expiratory pause (transrespiratory system pressure = 2 cmH2O) and during relaxed slow expiration from 20 to 0 cmH2O. Airway resistance decreased with age from 0.63 cmH2O·ml−1·s at 2 wk to 0.24 cmH2O·ml−1·s at 8 wk ( P < 0.001). Both tissue damping and tissue elastance decreased with age ( P < 0.001) from 2 to 5 wk, then plateaued through to 8 wk ( P < 0.001). This pattern was seen both in measurements taken at end-expiratory pause and during expiration. There were no age-related changes seen in hysteresivity when measured at end-expiratory pause, but the pattern of volume dependence did differ with the age of the mice. These changes in respiratory mechanics parallel the reported structural changes of the murine lung from the postnatal period into adulthood.