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Diseases associated with chronic respiratory failure have a negative impact on quality of life and life expectancy, notably through a reduction in patients' functional capacity. Assessing balance, coordination, muscular strength and endurance, as well as exercise tolerance, is therefore an important component of the evaluation of individuals with chronic respiratory failure. This evaluation can be made easier by using simple tools such as sit-to-stand tests. This review presents the main sit-to-stand tests that have been described and that can be used in everyday practice. The aim is to provide information to the clinician on the contribution of each test, and to identify the extent to which and the purpose for which these tests can be incorporated into a routine pulmonology and/or respiratory rehabilitation evaluation. Because of their inherently functional nature, these tests could help to identify the indications and/or the effects of respiratory rehabilitation., (Copyright © 2024 SPLF. Published by Elsevier Masson SAS. All rights reserved.)

Objective: To investigate the changes in predicted lung function measurements when using race-neutral equations in children, based upon the new Global Lung Initiative (GLI) reference equations, utilizing a race-neutral approach in interpreting spirometry results compared with the 2012 race-specific GLI equations., Study Design: We analyzed data from 2 multicenter prospective cohorts comprised of healthy children and children with history of severe (requiring hospitalization) bronchiolitis. Spirometry testing was done at the 6-year physical exam, and 677 tests were analyzed using new GLI Global and 2012 GLI equations. We used multivariable logistic regression, adjusted for age, height, and sex, to examine the association of race with the development of new impairment or increased severity (forced expiratory volume in the first second (FEV1) z-score ≤ -1.645) as per 2022 American Thoracic Society (ATS) guidelines., Results: Compared with the race-specific GLI, the race-neutral equation yielded increases in the median forced expiratory volume in the first second and forced vital capacity (FVC) percent predicted in White children but decreases in these two measures in Black children. The prevalence of obstruction increased in White children by 21%, and the prevalence of possible restriction increased in Black children by 222%. Compared with White race, Black race was associated with increased prevalence of new impairments (aOR 7.59; 95%CI, 3.00-19.67; P < .001) and increased severity (aOR 35.40; 95%CI, 4.70-266.40; P = .001). Results were similar across both cohorts., Conclusions: As there are no biological justifications for the inclusion of race in spirometry interpretation, use of race-neutral spirometry reference equations led to an increase in both the prevalence and severity of respiratory impairments among Black children., Competing Interests: Declaration of Competing Interest The study was supported by NIH grants U01 AI087881, R01 AI114552, R01 AI127507, and UH3 OD023253. The content of this manuscript is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health. The authors declare no conflicts of interest., (Copyright © 2024 Elsevier Inc. All rights reserved.)

In paediatrics, the pulmonary function test (PFT) is most often performed to support the diagnosis or in follow-up of asthma patients. Whatever the pathology responsible for respiratory symptoms and/or functional impairment, repeated PFTs make it possible to establish a prognosis (pulmonary function trajectories…) and to orient preventive interventions. PFT can be performed routinely from the age of three years, provided that the following requirements are met: suitable techniques and equipment, staff trained to apply the techniques and to receive young children, reference values for each technique indicating the limits of normal values and of between-test significant variation. From the age of three, children can be subjected to tidal breathing measurement of: resistance of the respiratory system (oscillometry, Rrs; airflow interruption, Rint) or of airways specific resistance (sRaw) and functional residual capacity (by applying a dilution technique). With maturity, the child will become capable of mobilizing his or her slow vital capacity to measure total lung capacity (TLC), once again by applying a dilution technique, then later by breathing against a closed shutter (plethysmography TLC and Raw). Finally, the child will be able to carry out forced expiration (forced spirometry) along with all of the other PFTs. It is important to take into account the paediatric adaptations specified in the international recommendations regarding the performance, reproducibility and quality of PFTs targeting this population., (Copyright © 2024 SPLF. Published by Elsevier Masson SAS. All rights reserved.)

Rationale: Area under expiratory flow-volume curve (AEX) has been shown to be a valuable functional measurement in respiratory physiology. Area under inspiratory flow-volume loop (AIN) also shows promise in characterizing upper and/or lower airflow obstruction., Objectives: we aimed here to develop normative reference values for AIN, able to ascertain deviations from normal., Methods: We analyzed AIN in 4,980 spirometry tests recorded in non-smoking, healthy individuals in the Pulmonary Function Testing Laboratory., Results: The mean (95% confidence interval, CI), standard deviation and median (25th-75th interquartile range) AIN were 16.05 (15.79-16.31), 9.08 and 14.72 (9.12-21.42) L2·sec-1, respectively. The mean (95% CI) and standard deviation of the best-trial measurements for square root of AIN (Sqrt AIN) were 3.84 (3.81-3.87) and 1.14; 4.15 (4.12-4.18) and 1.03 in men, and 2.68 (2.63-2.72) and 0.72 L·sec-1/2 in women. The mean (standard deviation) of pre- and post-bronchodilator Sqrt AIN were 3.71 (1.17) and 3.81 (1.19) L·sec-1/2, respectively. The mean (95% CI), standard deviation and lowest 5th percentile (lower limit of normal, LLN) of Sqrt AIN/Sqrt AEX (%) were 101.3 (100.82-101.88), 18.7, and 71.8%; stratified by gender, it was 102.2 (101.6-102.8), 18.6, and 72.8% in men, and 98 (96.9-99.2), 18.8, and 68.6% in women, respectively., Conclusions: The availability of area under the inspiratory flow-volume curve (AIN) and the derived indices offers a promising opportunity to assess upper airway disease (e.g., involvement of larynx, trachea or major bronchi), especially because some of these measurements appear to be independent of age, race, height, and weight., Competing Interests: The authors have declared that no competing interests exist., (Copyright: This is an open access article, free of all copyright, and may be freely reproduced, distributed, transmitted, modified, built upon, or otherwise used by anyone for any lawful purpose. The work is made available under the Creative Commons CC0 public domain dedication.)

Background: Adjustment for race is discouraged in lung-function testing, but the implications of adopting race-neutral equations have not been comprehensively quantified., Methods: We obtained longitudinal data from 369,077 participants in the National Health and Nutrition Examination Survey, U.K. Biobank, the Multi-Ethnic Study of Atherosclerosis, and the Organ Procurement and Transplantation Network. Using these data, we compared the race-based 2012 Global Lung Function Initiative (GLI-2012) equations with race-neutral equations introduced in 2022 (GLI-Global). Evaluated outcomes included national projections of clinical, occupational, and financial reclassifications; individual lung-allocation scores for transplantation priority; and concordance statistics (C statistics) for clinical prediction tasks., Results: Among the 249 million persons in the United States between 6 and 79 years of age who are able to produce high-quality spirometric results, the use of GLI-Global equations may reclassify ventilatory impairment for 12.5 million persons, medical impairment ratings for 8.16 million, occupational eligibility for 2.28 million, grading of chronic obstructive pulmonary disease for 2.05 million, and military disability compensation for 413,000. These potential changes differed according to race; for example, classifications of nonobstructive ventilatory impairment may change dramatically, increasing 141% (95% confidence interval [CI], 113 to 169) among Black persons and decreasing 69% (95% CI, 63 to 74) among White persons. Annual disability payments may increase by more than $1 billion among Black veterans and decrease by $0.5 billion among White veterans. GLI-2012 and GLI-Global equations had similar discriminative accuracy with regard to respiratory symptoms, health care utilization, new-onset disease, death from any cause, death related to respiratory disease, and death among persons on a transplant waiting list, with differences in C statistics ranging from -0.008 to 0.011., Conclusions: The use of race-based and race-neutral equations generated similarly accurate predictions of respiratory outcomes but assigned different disease classifications, occupational eligibility, and disability compensation for millions of persons, with effects diverging according to race. (Funded by the National Heart Lung and Blood Institute and the National Institute of Environmental Health Sciences.)., (Copyright © 2024 Massachusetts Medical Society.)

Importance: Removal of race correction in pulmonary function tests (PFTs) is a priority, given that race correction inappropriately conflates race, a social construct, with biological differences and falsely assumes worse lung function in African American than White individuals. However, the impact of decorrecting PFTs for African American patients with lung cancer is unknown., Objectives: To identify how many hospitals providing lung cancer surgery use race correction, examine the association of race correction with predicted lung function, and test the effect of decorrection on surgeons' treatment recommendations., Design, Setting, and Participants: In this quality improvement study, hospitals participating in a statewide quality collaborative were contacted to determine use of race correction in PFTs. For hospitals performing race correction, percent predicted preoperative and postoperative forced expiratory volume in 1 second (FEV1) was calculated for African American patients who underwent lung cancer resection between January 1, 2015, and September 31, 2022, using race-corrected and race-neutral equations. US cardiothoracic surgeons were then randomized to receive 1 clinical vignette that differed by the use of Global Lung Function Initiative equations for (1) African American patients (percent predicted postoperative FEV1, 49%), (2) other race or multiracial patients (percent predicted postoperative FEV1, 45%), and (3) race-neutral patients (percent predicted postoperative FEV1, 42%)., Main Outcomes and Measures: Number of hospitals using race correction in PFTs, change in preoperative and postoperative FEV1 estimates based on race-neutral or race-corrected equations, and surgeon treatment recommendations for clinical vignettes., Results: A total of 515 African American patients (308 [59.8%] female; mean [SD] age, 66.2 [9.4] years) were included in the study. Fifteen of the 16 hospitals (93.8%) performing lung cancer resection for African American patients during the study period reported using race correction, which corresponds to 473 African American patients (91.8%) having race-corrected PFTs. Among these patients, the percent predicted preoperative FEV1 and postoperative FEV1 would have decreased by 9.2% (95% CI, -9.0% to -9.5%; P < .001) and 7.6% (95% CI, -7.3% to -7.9%; P < .001), respectively, if race-neutral equations had been used. A total of 225 surgeons (194 male [87.8%]; mean [SD] time in practice, 19.4 [11.3] years) were successfully randomized and completed the vignette items regarding risk perception and treatment outcomes (76% completion rate). Surgeons randomized to the vignette with African American race-corrected PFTs were more likely to recommend lobectomy (79.2%; 95% CI, 69.8%-88.5%) compared with surgeons randomized to the other race or multiracial-corrected (61.7%; 95% CI, 51.1%-72.3%; P = .02) or race-neutral PFTs (52.8%; 95% CI, 41.2%-64.3%; P = .001)., Conclusions and Relevance: Given the findings of this quality improvement study, surgeons should be aware of changes in PFT testing because removal of race correction PFTs may change surgeons' treatment decisions and potentially worsen existing disparities in receipt of lung cancer surgery among African American patients.

Background: Few studies have examined whether baseline spirometry and the forced oscillation technique (FOT) would predict The COPD Assessment Test (CAT) score improvement after treatment of untreated COPD patients., Methods: The study subjects included 65 untreated COPD patients. They underwent the CAT, spirometry, and FOT (MostGraph) before and after treatment for more than 2 months. In addition, recursive partitioning analysis was performed using spirometry and the FOT parameters to identify the predictors of CAT improvement (CAT score ≥2)., Results: CAT scores and lung function significantly improved after treatment. Recursive partitioning analysis identified 3 improved classes, defined by Rrs at 20 Hz (R20), Xrs at 5 Hz (X5), and ΔX5, but not by spirometry. The accuracy of predicting CAT improvement was as follows: odds ratio, 25.3; 95 % confidence interval, 6.1 to 104.1; sensitivity, 91.2 %; specificity, 71.0 %; positive likelihood ratio, 3.14; and negative likelihood ratio, 0.12., Conclusions: FOT helps predict improved health status in untreated COPD patients., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Unexplained exertional dyspnoea or fatigue can arise from a number of underlying disorders and shows only a weak correlation with resting functional or imaging tests. Noninvasive cardiopulmonary exercise testing (CPET) offers a unique, but still under-utilised and unrecognised, opportunity to study cardiopulmonary and metabolic changes simultaneously. CPET can distinguish between a normal and an abnormal exercise response and usually identifies which of multiple pathophysiological conditions alone or in combination is the leading cause of exercise intolerance. Therefore, it improves diagnostic accuracy and patient health care by directing more targeted diagnostics and facilitating treatment decisions. Consequently, CPET should be one of the early tests used to assess exercise intolerance. However, this test requires specific knowledge and there is still a major information gap for those physicians primarily interested in learning how to systematically analyse and interpret CPET findings. This article describes the underlying principles of exercise physiology and provides a practical guide to performing CPET and interpreting the results in adults., (© 2022. The Author(s).)

Background: As the Coronavirus disease 2019 (COVID-19) is spreading worldwide, countries are dealing with different phases of the pandemic. Lately, scientific evidence has been growing about the measures for reopening respiratory outpatient services during the COVID-19 pandemic. We aim to summarize the key differences and similarities among recommendations by different national and international organizations., Methods: We searched on Google and Pubmed for recently published National and International Recommendations/Guidelines/Position Papers from professional organizations and societies, offering a guidance to physicians on how to safely perform pulmonary function testing during COVID-19 pandemic. We also searched for spirometry manufacturers' operational indications., Results: Indications on spirometry were released by the Chinese Task force, the American Thoracic Society, the European Respiratory Society, the Thoracic Society of Australia and New Zealand, the Société de Pneumologie de Langue Française, the Spanish Societies (Sociedad Espanola de Neumologia y Cirugia Toracica, Sociedad Espanola de Alergologia e Inmunologia Clinica, Asociacion de Especialistas en Enfermeria del trabajo, Asociacion de Enfermeria Comunitaria), the Sociedade Portuguesa de Pneumologia, the British Thoracic Society/Association for Respiratory Technology & Physiology, the Irish Thoracic Society, the Sociedad Uruguaya de Neumologia, the Italian Thoracic Society and the Italian Respiratory Society, Cleveland Clinic and Nebraska Medical Center. Detailed technical recommendations were found on manufacturers' websites. We found several similarities across available guidelines for safely resuming pulmonary function services, as well as differences in criteria for selecting eligible patients for which spirometry is deemed essential and advice which was not homogenous on room ventilation precautions., Conclusions: This study shows a synthesis of national/international guidelines allowing practicing physicians to adapt and shape the way to organize their outpatient services locally. There is generally good agreement on the importance of limiting pulmonary function testing to selected cases only. However, significant differences concerning the subsets of candidate patients, as well as on the management of adequate room ventilation, were observed., (Copyright © 2020 Sociedade Portuguesa de Pneumologia. Published by Elsevier España, S.L.U. All rights reserved.)

Effective specific airway resistance (sR eff ), its reciprocal the effective specific airway conductance (sG eff ) are computed as ratios between the integral of the resistive aerodynamic work of breathing (sWOB) and the integral of the tidal flow/volume loop, the reciprocal, respectively. Unfortunately, reference equations to obtain normative values for sR eff , sG eff , and sWOB are not yet available. To assess reference equations for sWOB, sR eff , and sG eff during tidal breathing at resting level in healthy infants, children, and adults by a multidimensional model. Retrospectively exported data were collected from databases of five Swiss lung function centers, in which plethysmography (Jaeger Würzburg, Germany) was performed for the assessment of airway dynamics, static lung volumes, and forced breathing flow-volume loops, in a collective of 28 healthy infants, 47 children, and 273 adults. From this cohort, reference equations were computed based on anthropometric measures, lung volumes, indices of the breathing pattern, and timing of breathing. By multi-linear modeling reference equations of sR eff , sG eff , and sWOB could be defined taking as independent parameters apart from anthropometric parameters, also parameters given by the ratio between the tidal volume and functional residual capacity (FRC pleth /V T ), and the ratio between V T and inspiratory time (V T /T I ). An alternative statistical approach to define reference equations of airway dynamics reveals that apart from the subject's anthropometric measurements, parameters of the magnitude of static lung volumes, the breathing pattern, and the timing of breathing are co-variants of reference equations of airway dynamics over a large age range., (© 2021 The Authors. Physiological Reports published by Wiley Periodicals LLC on behalf of The Physiological Society and the American Physiological Society.)

Management of patients with severe or critical COVID-19 is mainly modeled after care for patients with severe pneumonia or acute respiratory distress syndrome (ARDS) from other causes, and these recommendations are based on evidence that often originates from investigations in resource-rich intensive care units located in high-income countries. Often, it is impractical to apply these recommendations to resource-restricted settings, particularly in low- and middle-income countries (LMICs). We report on a set of pragmatic recommendations for acute respiratory failure and mechanical ventilation management in patients with severe/critical COVID-19 in LMICs. We suggest starting supplementary oxygen when SpO2 is persistently lower than 94%. We recommend supplemental oxygen to keep SpO2 at 88-95% and suggest higher targets in settings where continuous pulse oximetry is not available but intermittent pulse oximetry is. We suggest a trial of awake prone positioning in patients who remain hypoxemic; however, this requires close monitoring, and clear failure and escalation criteria. In places with an adequate number and trained staff, the strategy seems safe. We recommend to intubate based on signs of respiratory distress more than on refractory hypoxemia alone, and we recommend close monitoring for respiratory worsening and early intubation if worsening occurs. We recommend low-tidal volume ventilation combined with FiO2 and positive end-expiratory pressure (PEEP) management based on a high FiO2/low PEEP table. We recommend against using routine recruitment maneuvers, unless as a rescue therapy in refractory hypoxemia, and we recommend using prone positioning for 12-16 hours in case of refractory hypoxemia (PaO2/FiO2 < 150 mmHg, FiO2 ≥ 0.6 and PEEP ≥ 10 cmH2O) in intubated patients as standard in ARDS patients. We also recommend against sharing one ventilator for multiple patients. We recommend daily assessments for readiness for weaning by a low-level pressure support and recommend against using a T-piece trial because of aerosolization risk.

Background: While peak in- and expiratory flow rates offer valuable information for diagnosis and monitoring in respiratory disease, these indices are usually considered too variable to be routinely used for quantification in clinical practice., Objectives: The aim of the study was to obtain reproducible measurements of maximal inspiratory flow rates and to construct reference equations for peak in- and expiratory flows (PIF and PEF)., Method: With coaching for maximal effort, 187 healthy Caucasian subjects (20-80 years) performed at least 3 combined forced inspiratory and expiratory manoeuvres, until at least 2 peak inspiratory flow measurements were within 10% of each other. The effect on PIF preceded by a slow expiration instead of a forced expiration and PIF repeatability over 3 different days was also investigated in subgroups. Reference values and limits of normal for PIF, mid-inspiratory flow, and PEF were obtained according to the Lambda-Mu-Sigma statistical method., Results: A valid PIF could be obtained within 3.3 ± 0.6(SD) attempts, resulting in an overall within-test PIF variability of 4.6 ± 3.2(SD)%. A slow instead of a forced expiration prior to forced inspiration resulted in a significant (p < 0.001) but small PIF increase (2.5% on average). Intraclass correlation coefficient for between-day PIF was 0.981 (95% CI: 0.960-0.992). Over the entire age range, inter-subject PIF variability was smaller than in previous reports, and PIF could be predicted based on its determinants gender, age, and height (r2 = 0.53)., Conclusions: When adhering to similar criteria for the measurement of effort-dependent portions of inspiratory and expiratory flow-volume curves, performed according to current ATS/ERS standards, it is possible to obtain reproducible PIF and PEF values for use in routine clinical practice., (© 2021 S. Karger AG, Basel.)

An organ donor PaO2 above 40 kPa is generally required for lung transplantation. Point-of-care (POC) blood gas analyzers are commonly used by organ procurement organizations (OPO) but may underestimate the PaO2 at high levels. We hypothesized that changing to a more accurate blood gas analyzer would result in additional lungs transplanted. All PaO2 measurements on organ donors managed at one OPO's recovery center were performed on an i-STAT POC analyzer prior to October 2015, and on a GEM 4000 subsequently. For 24 weeks, all blood gases were tested simultaneously on both analyzers. We compared lung outcomes of 147 donors in the year prior to this change (using the i-STAT) with 56 donors in the 24-week study period (using the GEM 4000 for lung allocation). When the PaO2 was above 40 kPa, the i-STAT PaO2 was 7.2 kPa lower on average than the GEM 4000. When the GEM PaO2 measured between 40 and 50 kPa, the corresponding i-STAT PaO2 value registered less than 40 kPa 25 out of 48 times (52%), with an average difference of 7.3 kPa (SD = 2.9). The rate of lungs transplanted using the GEM 4000 was 48% compared with 35% in the year prior using the i-STAT ( p  = .11), with equivalent recipient outcomes. The i-STAT analyzer underestimated the PaO2 above 40 kPa and changing to a more accurate PaO2 analyzer may increase lungs transplanted.

Objectives: To assess the test-retest reliability of inspiratory load detection and load magnitude perception tests in healthy volunteers., Design: Cohort of convenience., Setting: Respiratory physiology laboratory., Participants: Twenty healthy adults., Interventions: On two separate occasions participants performed tests of inspiratory loading. Participants breathed through custom made resistive tubing and were asked to indicate when they detected a different resistance during inspiration. In a second test participants rated the magnitude of presented inspiratory loads using the modified Borg score., Main Outcome Measures: Intra-class Correlation Coefficient (ICC 2,1 ) values for repeated tests of inspiratory load detection threshold and load magnitude rating., Results: ICC 2,1 values ranged from 0.657-0.786 for load detection testing and 0.739 to 0.969 for rating of load magnitude., Conclusions: The tests are simple and reliable measures of inspiratory load detection and magnitude rating. They can be used in future research to determine the effectiveness of interventions to reduce the effort of breathing in health and disease., (Crown Copyright © 2020. Published by Elsevier B.V. All rights reserved.)

Background: Pseudomonas aeruginosa (PA) status influences management decisions in cystic fibrosis (CF) but diagnostic approaches vary. We evaluated the ability of the CFHealthHub (CFHH) criteria, which consist of two major and four minor statements, in diagnosing chronic PA infection among adults with CF., Methods: In this retrospective cross-sectional analysis, we compared the CFHH criteria against the Leeds criteria. Data were collected between 1st January and 31 st December 2016 from all adults with CF receiving care at Sheffield, excluding those with lung transplantation (n = 7) or on ivacaftor (n = 13). The CFHH criteria PA status were cross-tabulated against the Leeds criteria, and clinical outcomes between chronic PA vs non chronic PA for both criteria were compared., Results: This analysis included 186 adults with CF (90 females, median age 27 years, median baseline FEV 1 78.5%). The CFHH criteria diagnosed more cases of chronic PA (116/186, 62.4% vs 79/186, 42.5%), and 37/107 cases of non-chronic PA according to the Leeds criteria were deemed chronic PA by the CFHH criteria. The magnitude of difference in %FEV 1 decline between chronic PA vs non chronic PA was slightly greater for the CFHH criteria (-0.6%, 95% CI -1.8 to 0.6%) compared to the Leeds criteria (-0.2%, 95% CI -1.3 to 1.0%)., Conclusions: The CFHH criteria detected more chronic PA cases yet still retained similar levels of discrimination for health outcomes in comparison to the Leeds criteria. These findings provide preliminary evidence for the validity of the CFHH criteria among adults with CF., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Peak cough flow represents an important metric directly related to the physiologic ability of an individual to defend the airway or expel tracheal aspirate. Given the high prevalence of dysphagia and dystussia in individuals with amyotrophic lateral sclerosis (ALS) and recent findings that the expiratory phase of voluntary cough is significantly impaired in ALS individuals, we aimed to determine the reproducibility of an affordable, portable peak cough flow (PCF) meter for the assessment of cough production in individuals with ALS. 109 individuals with ALS completed voluntary cough testing using both the research cough spirometry equipment and a digital peak cough flow meter. Maximum peak expiratory cough flow rates were obtained from each device. Analyses included paired t test, Pearson's correlation, and Lin's concordance correlation to determine the degree of agreement and reproducibility between cough measurement devices (alpha = 0.05). Mean differences between peak cough flow test values (L/min) across instruments were not statistically significant (mean difference =  - 2.93; 95% CI - 18.67, 12.82; p = 0.713). PCF values obtained from the digital peak cough flow meter and the research cough spirometry equipment were strongly associated (r = 0.826, p < 0.000) and demonstrated a high level of agreement and reproducibility (ρ c  = 0.824, 95% CI 0.754, 0.876). These data validate the use of an inexpensive and portable digital peak cough flow device to index peak cough flow strength in individuals with ALS. This assessment could easily be incorporated into a multidisciplinary ALS clinical setting to index the physiologic ability of an individual to protect the airway.

Background: The lung clearance index (LCI), derived from the Multiple Breath Washout (MBW) test, is sensitive to treatment effects and compared with spirometry has higher feasibility in younger children and requires smaller sample sizes. As a result, the LCI has been endorsed by the European CF Society Clinical Trials Network for use as a primary outcome measure in CF clinical trials., Methods: Here we describe the implementation of standardised protocols for MBW test performance, data collection and quality control to successfully incorporate LCI as a novel outcome measure in a large multicentre phase III clinical trial., Results: Three regional (North America (NA), Europe (EU), Australia (AUS)) central over-reading centres (CORC) were established to provide a collaborative platform for MBW training, certification and quality control of data. One hundred and thirty-two naïve operators from 53 sites across NA, EU and AUS were successfully trained and certified to perform MBW testing.  Incorporation of a re-screening opportunity in the study protocol resulted a final screening feasibility rate of 93%, success remained high throughout the study resulting in an overall feasibility of MBW study data of 88.1% (1107/1257). MBW test acceptability was similar between geographical regions: NA (88%), EU (89%) and AUS (89%)., Conclusion: With this approach we achieved high MBW test feasibility and sustained collection of good quality data, demonstrating the utility of LCI as an effective primary endpoint in the first international phase III clinical trial to report LCI as the primary outcome., (Copyright © 2019. Published by Elsevier B.V.)

Objective: The objective of this literature review is to gather all the LFT norms available for the Tunisian population, as well as QDV questionnaires specific to chronic respiratory patients that have been validated in Tunisia., Methods: This review included a literature search using the PubMed and Sciencedirect databases. The reference lists of the retrieved English/French articles were searched for any additional reference. Specific research has been carried out for each stage of the natural evolution of chronic diseases. For LFT used in the exploration of deficiency, the key-words were ("respiratory function test" OR "spirometry" OR "plethysmography" OR "exhaled fraction of oxide nitric" OR "lung diffusion" OR "peak nasal inspiratory flow" OR "Lung age") AND ("Tunisia" OR "North Africa") AND ("reference equation" OR "reference value" OR "standard reference"). For LFT used in the exploration of incapacity, the key-words were ("exercise test" OR "maximal oxygen uptake" OR "cardiorespiratory test" OR "six minute walk distance" OR "six-minute walk distance" OR "6-minute walk distance" OR "six-min walk distance" OR "6-min walk distance" OR "six minute walking distance" OR "six-minute walking distance" OR "6MWD") AND ("Tunisia" OR "North Africa") AND ("reference equation" OR "reference value" OR "standard reference"). For the QOL questionnaires used in pneumology, the key-words were: ("quality of life" OR "QOL") AND ("respiratory" OR "pulmonology") AND ("Tunisia" OR "North Africa")., Results: As part of deficiency exploration, 11 Tunisian norms are available. As part of incapacity exploration, three Tunisian norms are available for the 6-minute walk test. Only one QOL questionnaire specific to chronic respiratory patients has been validated in Tunisia., Conclusion: Despite its richness, the Tunisian "bank" of norms for LFT and QOL questionnaires has yet to be enriched.

Background: A predictive scoring system for acute respiratory distress syndrome (ARDS) patients, which incorporates age, PaO 2 /FlO 2 , and plateau pressure, APPS, was developed recently. It was validated externally in a Caucasian population but has not been studied in Asian populations. The aim of this study was to validate APPS in Korean ARDS patients., Methods: We retrospectively reviewed the medical records of patients who were diagnosed with ARDS using the Berlin criteria and admitted to the medical ICU at Seoul National University Hospital from January 2015 to December 2016. The validation of the APPS was performed by evaluating its calibration and predictive accuracy. Its calibration was plotted and quantified using the Hosmer-Lemeshow test. Its predictive accuracy was assessed by calculating the area under the receiver operating characteristics (AUC-ROC) curve., Results: A total of 116 patients were analyzed, 32 of whom survived. Of the 116 patients, 11 (9.5%) were classified as APPS grade 1 (score 3-4), 88 (75.9%) as grade 2 (score 5-7) and 17 (14.6%) as grade 3 (score 8-9). In-hospital mortality was 27.3% for grade 1, 73.9% for grade 2 and 94.1% for grade 3 (P for trend < 0.001). The APPS was well calibrated (Hosmer-Lemeshow test, P = 0.578) and its predictive accuracy was acceptable (AUC-ROC 0.704, 95% confidence interval 0.599-0.809)., Conclusions: The APPS predicted in-hospital mortality in Korean patients with ARDS with similar power to its application in a Western population and with acceptable predictive accuracy., Trial Registration: Retrospectively registered.

Coronavirus disease 2019 (COVID-19) is transmitted mainly by respiratory droplets and close contact, probably by aerosol. Pulmonary function testing procedures have been associated with an increasing risk of COVID-19 transmission among patients/subjects and medical staffs. Effective prevention and control strategies must be compulsorily implemented to prevent nosocomial infection. This recommendation is intended to be followed by healthcare workers (HCWs) of pulmonary function testing laboratory when COVID-19 is in epidemic. Based on the features of pulmonary function testing, precaution principles and considerations are developed in three aspects of management for HCWs, operating procedure, environment and equipment. Indications of pulmonary function testing should be followed strictly. It is strongly recommended to suspend the test for the confirmed or suspected cases of COVID-19 during the contagious stage, and to postpone the test for other patients if it is not imperative. Medical personnel should mandatorily adhere to the standard stratification of precaution measures. Patients/Subjects should be isolated in a separate area for testing. Disposable in-line filters must be used during pulmonary function testing. Cleaning and disinfection procedures for environment and equipment in pulmonary function testing laboratory should be paid more attention.

Background: The Global Lung Function Initiative attempted to formulate global all-age lung function equations. The suitability of these equations to Middle Eastern children was never evaluated; this study will evaluate these equations in addition to other regional ones., Methods: Spirometry was conducted for 582 (311 boys) healthy 6- to 13-year-old Jordanian children. z scores, predicted values, percent predicted values, and frequency of records below lower limit than normal (LLN) were calculated for each child using the studied equations., Results: Although none of the studied equations produced a perfect representation of the study data, the GLI 2012 equations for Caucasians were the most suitable., Conclusion: GLI 2012 equations for Caucasians are a reasonable fit for Jordanian school-aged children., (© 2020 Wiley Periodicals, Inc.)

Purpose: Patients with neuromuscular disease (NMD) experience weakened cough due to progressive respiratory muscle weakness. Peak cough flow (PCF) measurements derived from adult populations are used to recommend initiation of assisted cough therapies. The objective of this study was to characterize PCF values among pediatric patients with NMD., Methods: Retrospective chart review was performed for patients seen in the multidisciplinary pediatric muscular dystrophy clinic from 2010 to 2016. Clinical and demographic variables included age, gender, ambulation status, and PCF measurements., Results: 366 patients with an established diagnosis of NMD (median age 11.8 years) were included in this study. 102 (27.8%) out of the 366 patients were affected by Duchenne muscular dystrophy (DMD), 42 (11.5%) by congenital muscular dystrophy (CMD), 42 (11.5%) by Charcot Marie Tooth disease (CMT) and 24 (6.5%) by Becker's muscular dystrophy (BMD). The mean PCF values in DMD (255.8 L/min) and CMD (249.1 L/min) were lower than CMT (321.5 L/min) with p-values of 0.007 and 0.02, respectively. The mean PCF of BMD (333.3 L/min) was higher than that of DMD and CMD but the difference was not statistically significant. PCFs were not statistically different between ambulatory and non-ambulatory status (263.0 L/min versus 290.8 L/min, p = 0.12). Children under 10 years of age had lower PCF relative to older subjects (179.5 L/min versus 300.9 L/min, p < 0.0001)., Conclusion: Baseline PCF values in young children are below the adult-specific values suggested for starting assisted cough techniques. Further longitudinal trials are required to derive pediatric-specific reference values for PCF in patients with NMD.

The optimal method for respiratory muscle endurance (RME) assessment remains unclear. This study assessed the test-retest reliability of two RME-test methodologies. Fifteen healthy adults attended the laboratory on four occasions, separated by 5 ± 2 days, and completed each test in a random, "one on two" order. They performed spirometry testing, maximal respiratory pressure assessment and two different RME tests: an inspiratory resistive breathing (IRB) and an isocapnic hyperpnea endurance (IHE) test. Typical error, expressed as coefficient of variation, for IRB maximal inspiratory pressure (MIP) and IHE maximal ventilation were 12.21 (8.85-19.67) % and 10.73 (7.78-17.29) %, respectively. Intraclass correlation coefficients for the same parameters were 0.83 (0.46-0.94) and 0.80 (0.41-0.93), respectively. No correlations were found between RME parameters derived from the IHE and IRB tests (all p > 0.05). Significant positive correlations were found between both IRB and IHE outcomes and spirometry parameters, MIP and maximal expiratory pressure (p < 0.05). Given these results, IRB and IHE appear to be suitable for RME testing in healthy people, although they may reflect different physiological mechanisms (respiratory mechanics and respiratory muscle capacity for IHE test vs. inspiratory muscle capacity for IRB test). Future studies are therefore warranted that compare IRB and IHE tests in clinical settings., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Objective: To develop a normal reference range of Infant pulmonary function test (IPFT) indices for Indian children., Study Design: Prospective birth cohort study., Setting: Division of Pediatric Pulmonology of a tertiary-care institute in India from August 2012 to March 2017., Participants: All neonates born at the institute during the study period were screened for eligibility., Measurement: IPFT at baseline and every 6-month until 36-months of age., Main Outcome Measure(s): Tidal breathing flow-volume loop (TBFVL), Rapid thoracoabdominal compression (RTC), and Raised volume RTC (RVRTC) indices at baseline and follow-up., Results: 310 newborns were enrolled in the cohort; 281 of them (169 male) had completed 36-months of follow-up at the end of the study period. There was no influence of gender on the baseline IPFT indices. Tidal volume per unit body weight (VT/kg) significantly increased from baseline to 36 months of age (P<0.001) while the peak ratio (tPTEF/tE) initially decreased in first 18-months of age (P<0.001), after that returned to the baseline value by 36 months of age. RTC indices did not change significantly from baseline values. In RVRTC, the ratio of forced expiratory volume in 0.5s to forced vital capacity (FEV0.5/FVC) was significantly decreased from baseline to 36 months of age (P=0.002)., Conclusions: Normal values for various IPFT indices for TBFVL, RTC, and RVRTC from neonates to the age of 36-month are provided. These data may be used as normative data for healthy neonates and children of Indian origin.

Breathing rate and depth influence the concentration of carbon dioxide in the blood, altering cerebral blood flow and thus functional magnetic resonance imaging (fMRI) signals. Such respiratory fluctuations can have substantial influence in studies of fMRI signal covariance in subjects at rest, the so-called "resting state functional connectivity" technique. If respiration is monitored during fMRI scanning, it is typically done using a belt about the subject's abdomen to record abdominal circumference. Several measures have been derived from these belt records, including the windowed envelope of the waveform (ENV), the windowed variance in the waveform (respiration variation, RV), and a measure of the amplitude of each breath divided by the cycle time of the breath (respiration volume per time, RVT). Any attempt to gauge respiratory contributions to fMRI signals requires a respiratory measure, but little is known about how these measures compare to each other, or how they perform beyond the small studies in which they were initially proposed. Here, we examine the properties of these measures in hundreds of healthy young adults scanned for an hour each at rest, a subset of the Human Connectome Project chosen for having high-quality physiological records. We find: 1) ENV, RV, and RVT are all correlated, and ENV and RV are more highly correlated to each other than to RVT; 2) respiratory events like deep breaths exhibit characteristic heart rate elevations, fMRI signal changes, head motions, and image quality abnormalities time-locked to large deflections in the belt traces; 3) all measures can "miss" deep breaths; 4) RVT "misses" deep breaths more than ENV or RV; 5) all respiratory measures change systematically over the course of a 14.4-min scan. We discuss the implications of these findings for the literature and ways to move forward in modeling respiratory influences on fMRI scans., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Background: New-generation ventilators display dynamic measures of respiratory mechanics, such as compliance, resistance, and auto-PEEP. Knowledge of the respiratory mechanics is paramount to clinicians at the bedside. These calculations are obtained automatically by using the least squares fitting method of the equation of motion. The accuracy of these calculations in static and dynamic conditions have not been fully validated or examined in different clinical conditions or various ventilator modes., Methods: A bench study was performed by using a lung simulator to compare the ventilator automated calculations during passive and active conditions. Three clinical scenarios (normal, COPD, and ARDS) were simulated with known compliances and resistance set per respective condition: normal (compliance 50 mL/cm H 2 O, resistance 10 cm H 2 O/L/s), COPD (compliance 60 mL/cm H 2 O, resistance 22 cm H 2 O/L/s), and ARDS (compliance 30 mL/cm H 2 O, and resistance 13 cm H 2 O/L/s). Each scenario was subjected to 4 different muscle pressures (P mus ): 0, -5, -10, and -15 cm H 2 O. All the experiments were done using adaptive support ventilation. The resulting automated dynamic calculations of compliance and resistance were then compared based on the clinical scenarios., Results: There was a small bias (average error) and level of agreement in the passive conditions in all the experiments; however, these errors and levels of agreement got progressively higher proportional to the increased P mus . There was a strong positive correlation between P mus and compliance measured as well as a strong negative correlation between P mus and resistance measured., Conclusions: Automated displayed calculations of respiratory mechanics were not dependable or accurate in active breathing conditions. The calculations were clinically more reliable in passive conditions. We propose different methods of calculating P mus , which, if incorporated into the calculations, would improve the accuracy of respiratory mechanics made via the least squares fitting method in actively breathing conditions., Competing Interests: The authors have disclosed no conflicts of interest., (Copyright © 2019 by Daedalus Enterprises.)

Background: Spirometry is the most common pulmonary function test. It is widely used in the assessment of lung function to provide objective information used in the diagnosis of lung diseases and monitoring lung health. In 2005, the American Thoracic Society and the European Respiratory Society jointly adopted technical standards for conducting spirometry. Improvements in instrumentation and computational capabilities, together with new research studies and enhanced quality assurance approaches, have led to the need to update the 2005 technical standards for spirometry to take full advantage of current technical capabilities. Methods: This spirometry technical standards document was developed by an international joint task force, appointed by the American Thoracic Society and the European Respiratory Society, with expertise in conducting and analyzing pulmonary function tests, laboratory quality assurance, and developing international standards. A comprehensive review of published evidence was performed. A patient survey was developed to capture patients' experiences. Results: Revisions to the 2005 technical standards for spirometry were made, including the addition of factors that were not previously considered. Evidence to support the revisions was cited when applicable. The experience and expertise of task force members were used to develop recommended best practices. Conclusions: Standards and consensus recommendations are presented for manufacturers, clinicians, operators, and researchers with the aims of increasing the accuracy, precision, and quality of spirometric measurements and improving the patient experience. A comprehensive guide to aid in the implementation of these standards was developed as an online supplement.

Introduction: People with Down syndrome (DS) have high respiratory morbidity, evaluating their respiratory health with standardized, objective tests is desirable. Thus, the objective of this study was to evaluate the technical quality of Pulmonary Function Tests (PFTs) to determine which ones are most suitable for this population., Methods: Participants included children, teenagers and adults with DS, 5 years of age or older (n=302). The technical quality of the impulse oscillometry system (IOS), forced spirometry, lung-diffusing capacity for carbon monoxide (DL CO ), and 6-min walk test (6MWT) were analyzed by age group. Capnography and pulse oximetry were included in the study. Technical quality was determined on the basis of current international PFTs standards., Results: Fifty-one percent of participants were males. A total of 184 participants (71%) who completed the IOS fulfilled the quality criteria, while 210 (70%) completed the 6MWT. Performance on forced spirometry and DL CO was poor. All pulse oximetries and 96% percent heart rates obtained had good quality, but exhaled carbon dioxide (PetCO 2 ) and respiratory rate (RR) showed deficient repeatability., Conclusions: IOS appears to be the most reliable instrument for evaluating lung mechanics in individuals with DS., (Copyright © 2019 SEPAR. Publicado por Elsevier España, S.L.U. All rights reserved.)

Background: Animal models and, in particular, mice models, are important tools to investigate the pathogenesis of respiratory diseases and to test potential new therapeutic drugs. Lung function measurement is a key step in such investigation. In mice, it is usually performed using forced oscillation technique (FOT), negative pressure-driven forced expiratory (NPFE) and pressure-volume (PV) curve maneuvers. However, these techniques require a tracheostomy, which therefore only allows end-point measurements. Orotracheal intubation has been reported to be feasible and to give reproducible lung function measurements, but the agreement between intubation and tracheostomy generated-data remains to be tested., Methods: Using the Flexivent system, we measured lung function parameters (in particular, forced vital capacity (FVC), forced expiratory volume in the first 0.1 s (FEV0.1), compliance (Crs) of the respiratory system, compliance (C) measured using PV loop and an estimate of inspiratory capacity (A)) in healthy intubated BALB/cJ mice and C57BL/6 J mice and compared the results with similar measurements performed in the same mice subsequently tracheostomized after intubation, by means of paired comparison method, correlation and Bland-Altman analysis. The feasibility of repetitive lung function measurements by intubation was also tested., Results: We identified parameters that are accurately evaluated in intubated animals (i.e., FVC, FEV0.1, Crs, C and A in BALB/cJ and FVC, FEV0.1, and A in C57BL/6 J). Repetitive lung function measurements were obtained in C57BL/6 J mice., Conclusion: This subset of lung function parameters in orotracheally intubated mice is reliable, thereby allowing relevant longitudinal studies.

Introduction: The validity of the published plethysmographic reference equations specific to adults living in Eastern Algeria (RE-EA) in the interpretation of spirometric results in adult natives of Northern Algeria has not been assessed., Aim: To test the application of the RE-EA (Constantine, mean altitude=694m) to a population of healthy adults living in Algiers (mean altitude=153m)., Methods: The plethysmographic parameters of 453 healthy adults living in Algiers (234 women; age: 45±15 years, height: 1.66±0.10m, weight: 73±14kg) were determined and were compared with those predicted from the RE-EA. In addition, the percentages of adults with an obstructive ventilatory defect (OVD), a restrictive ventilatory defect (RVD) and/or lung hyperinflation were noted. The RE-EA are considered inapplicable to healthy adults living in Algiers if, firstly, the differences between the determined and predicted plethysmographic parameters are statistically significant and, secondly, more than 5% of healthy adults have OVD and/or RVD and/or lung hyperinflation., Results: The RE-EA significantly overestimated the following parameters: FEV1 by 0.27±0.39L, MMEF by 0.52±0.75L/s, FEF25% by 0.75±0.56L/s, FEF50% by 0.85±1.02L/s, FEF75% by 0.28±1.25L/s, VC by 0.21±0.50L, TLC by 0.31±0.62L, ERV by 0.06±0.48L, IC by 0.27±0.48L, FEV1/VC by 0.03±0.05, and FEV1/FVC by 0.03±0.05. They significantly underestimated the RV/TLC by 0.01±0.05. Moreover, 14.35 %, 8.83 % and 5.74 % of healthy adults had OVD, RVD and lung hyperinflation, respectively., Conclusion: The RE-EA are not applicable in adult natives of Northern Algeria., (Copyright © 2019 SPLF. Published by Elsevier Masson SAS. All rights reserved.)

Introduction : Motor neuron disease (MND) causes respiratory insufficiency, which is managed in part through use of noninvasive ventilation (NIV). Guidelines for the initiation of NIV are based on pulmonary function tests (PFTs), usually performed once every three months. In the setting of MND telemedicine, remote monitoring of respiratory health may permit earlier intervention, but proof of equivalence to conventional PFTs is lacking. Methods : We implemented delivery of remote PFTs (rPFTs), based on our institution's telemedicine platform, with the goals of validating measurement equivalence to conventional forced vital capacity (FVC) and maximal inspiratory pressure (MIP) assessments, and assessing process acceptability from both patients and therapists. Results : When remotely guided by a respiratory therapist, 40 patient/caregiver teams produced respiratory parameters that were tightly correlated with those acquired through the standard evaluation. Both patients and therapists generally rated the setup and use of the devices positively, with patient ratings higher than those of the therapists. Discussion : This study suggests that rPFTs are accurate and acceptable, and thus may be incorporated into MND telemedicine for clinical and research use.

For more accurate lung evaluation in ex vivo lung perfusion (EVLP), we have devised a new parameter, PaO 2 /FiO 2 ratio difference (PFD); PFD 1-0.4  = P/F ratio at FiO 2 1.0 - P/F ratio at FiO 2 0.4. The aim of this study is to compare PFD and transplant suitability, and physiological parameters utilized in cellular EVLP. Thirty-nine human donor lungs were perfused. At 2 h of EVLP, PFD 1-0.4 was compared with transplant suitability and physiological parameters. In a second study, 10 pig lungs were perfused in same fashion. PFD 1-0.4 was calculated by blood from upper and lower lobe pulmonary veins and compared with lobe wet/dry ratio and pathological findings. In human model, receiver operating characteristic curve analysis showed PFD 1-0.4 had the highest area under curve, 0.90, sensitivity, 0.96, to detect nonsuitable lungs, and significant negative correlation with lung weight ratio (R 2  = 0.26, P < 0.001). In pig model, PFD 1-0.4 on lower and upper lobe pulmonary veins were significantly associated with corresponding lobe wet/dry ratios (R 2  = 0.51, P = 0.019; R 2  = 0.37, P = 0.060), respectively. PFD 1-0.4 in EVLP demonstrated a significant correlation with lung weight ratio and allowed more precise assessment of individual lobes in detecting lung edema. Moreover, it might support decision-making in evaluation with current EVLP criteria., (© 2019 Steunstichting ESOT.)

We propose that tongue protrusive strength and tone may be related to upper airway patency, and when protrusive strength is reduced, individuals are at higher risk of developing sleep apnea, or speech/swallow disorders. The goal of the current study was to determine normative values of maximum tongue protrusion force (MTPF) in healthy young adults, using a unique newly developed device. We hypothesized that MTPF would be greater in males than in females. One hundred and one healthy young adults (mean age: 22.99 years; male: 23, female: 78) participated in this study. The subjects pushed their tongue forward against the device's piston (protrusion) as hard as possible for 2-5 sec and MTPF was recorded in Newtons (N). A minimum of 5 MTPF measurements were obtained with 1-2 min rest between measurements. The average MTPF for all subjects was 15.4 N (SD: ±3.8), with a range of 8-29. The male average MTPF was higher than female (17.8 N, SD: ±3.7 vs. 14.7 N, SD: ±3.5; P = 0.001). There was no significant difference for age between males and females; males had significantly greater height and weight. The results demonstrate our novel device can effectively measure tongue protrusive force in healthy young adults. This study provides normative values for MTPF, and identified significant tongue protrusion strength differences between males and females., (© 2019 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of The Physiological Society and the American Physiological Society.)

Objectives/hypothesis: Phonation threshold pressure (PTP), the minimum subglottal pressure (P s ) required for phonation, is sensitive to changes in laryngeal biomechanics and is often elevated with pathology. Little is reported on PTP in children; challenges with task performance and measurement reliability represent barriers to routine clinical assessment., Study Design: Pilot study evaluating PTP and P s measurement reliability in children using labial and mechanical interruption., Methods: Twenty-two subjects aged 4 to 17 years (10.7 ± 3.9 years) participated. Ten trials were performed for each method; task order was randomized. For labial interruption, subjects produced /pα/ five times at softest (onset PTP) and comfortable amplitude. For mechanical interruption, subjects produced a sustained /α/ while a balloon valve interrupted phonation five times for 250 ms each; mechanical interruption was performed with a mouthpiece and mask. PTP was recorded as the difference between P s and supraglottal pressure at phonation cessation (offset PTP). Mean PTP and P s and intrasubject coefficients of variation were compared. Correlations with age were evaluated., Results: Mean PTP (P < .001) and P s (P = .005) were higher for labial interruption. Intrasubject coefficients of variation for PTP (P = .554) and P s (P = .305) were similar across methods. Coefficient of variation was related to age for mechanical-mask trials only (r = -0.628, P = .00175)., Conclusions: Differences in means are likely related to differences in task and PTP hysteresis effect. Reliability is comparable with all methods; using a mouthpiece may be preferable to a mask for mechanical interruption. Measurement of PTP is noninvasive, reliable, and may be a useful adjunct in pediatric voice assessment., Level of Evidence: 3b Laryngoscope, 129:1520-1526, 2019., (© 2018 The American Laryngological, Rhinological and Otological Society, Inc.)

Background: Obstructive lung disease is diagnosed by a decreased ratio of FEV 1 to the vital capacity (VC). Although the most commonly used VC is FVC, American Thoracic Society guidelines suggest alternative VCs, for example, slow VC (SVC), may offer a more-accurate evaluation of breathing capacity. There is recent evidence that using only FEV 1 /FVC underrecognizes obstruction in subjects at high risk and who are symptomatic. Previous studies have indicated that healthy individuals show a minimum difference between FVC and SVC; however, testing of individuals with asthma and who are symptomatic indicates that SVC can be markedly larger than FVC., Objective: To evaluate the differences among SVC, FVC, and SVC-based measurements in the diagnosis of symptomatic obstructive lung disease., Methods: A retrospective analysis was performed of spirometry and plethysmography measurements from studies conducted between 2011 to 2015. We established a pulmonary function database that incorporated predictive equations from the National Health and Nutrition Examination Survey III (NHANES III). The SVC to FVC difference was calculated. FEV 1 /SVC was compared with FEV 1 /FVC by using NHANES III lower limit of normal values., Results: A total of 2,710 studies with 2,244 subjects were reviewed. Spirometric obstruction, as defined by NHANES III, was identified in 26.1% of the studies (707/2,710). The mean (± SD) difference between SVC and FVC was 375.0 ± 623.0 mL and 258.8 ± 532.5 mL in those with and those without obstruction, respectively. Subgroup and multivariate analysis demonstrated age, body mass index, and FEV 1 associated contributions to the difference between SVC and FVC. By using FEV 1 /SVC, the prevalence of obstruction increased from 26.1 to 45.0% (1,219/2,710) and identified 566 additional studies of subjects with obstruction. Fifty-four percent of the subjects with newly-identified obstructive lung disease (305/566) had smoking histories, and 67.4% (345/512) received medications for obstructive lung disease., Conclusions: The isolated use of FVC-based diagnostic algorithms did not recognize individuals with symptomatic obstructive lung disease. Recognizing the difference between SVC and FVC measurements in subjects will improve testing and diagnosis of obstructive lung disease., (Copyright © 2019 by Daedalus Enterprises.)

Monitoring of respiratory mechanics is required for guiding patient-specific mechanical ventilation settings in critical care. Many models of respiratory mechanics perform poorly in the presence of variable patient effort. Typical modelling approaches either attempt to mitigate the effect of the patient effort on the airway pressure waveforms, or attempt to capture the size and shape of the patient effort. This work analyses a range of methods to identify respiratory mechanics in volume controlled ventilation modes when there is patient effort. The models are compared using 4 Datasets, each with a sample of 30 breaths before, and 2-3 minutes after sedation has been administered. The sedation will reduce patient efforts, but the underlying pulmonary mechanical properties are unlikely to change during this short time. Model identified parameters from breathing cycles with patient effort are compared to breathing cycles that do not have patient effort. All models have advantages and disadvantages, so model selection may be specific to the respiratory mechanics application. However, in general, the combined method of iterative interpolative pressure reconstruction, and stacking multiple consecutive breaths together has the best performance over the Dataset. The variability of identified elastance when there is patient effort is the lowest with this method, and there is little systematic offset in identified mechanics when sedation is administered., (Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.)

Background and Objective: To investigate the relationship between infant-specific preoperative pulmonary function tests (PFTs) and postoperative pulmonary complications (PPCs) in infants with congenital heart diseases (CHDs)., Methods: Patients of 1-3 years of age who received surgical treatment for CHDs from January 1 st , 2009, to December 31 st , 2017, were retrieved. Records of preoperative PFTs, methods of operation, anesthesia procedures, intraoperative vital signs, respiratory support modalities, and PPCs was retrieved and analyzed., Results: 122 infants met the preset inclusion criteria, including 72 males and 50 females. There were 76 cases of thoracotomy and 46 cases of cardiac catheterization. The overall incidence of PPCs was 15.6%, including 19.7% after thoracotomy and 8.7% after cardiac catheterization, respectively ( p > 0.05). The incidence of PPCs was 35.4% or 2.7% in infants with a rapid or a normal respiratory rate, respectively; 42.1% or 3.6% in infants with an abnormal or a normal time to reach peak tidal expiratory flow versus the total expiratory time (TPTEF/TE), respectively; 39.0% or 3.7% in infants with an abnormal or a normal volume to peak expiratory flow versus the total expiratory volume (VPEF/VE), respectively; and 46.9% or 4.4% in infants with a decreased or a normal lung compliance, respectively ( p < 0.01 in all comparisons)., Conclusions: The preoperative abnormal changes in respiratory rate, TPTEF/TE, VPEF/VE, and lung compliance are indicative of the risk of PPCs.

Ventilation and perfusion lung imaging with SPECT/CT permits accurate delineation of the individual lobes of the lungs using the CT images for use in ascribing the relative functional contribution to overall lung function of the lobes of both ventilation and perfusion. Moreover, an advantage of using Technegas as the ventilation agent and radiolabelled macro-aggregated albumin microspheres as the perfusion agent is that the deposition pattern is fixed upon administration and thus different patient postures can be studied and the effect of gravity and position determined, even though the scans must be acquired with the subject supine using conventional gamma camera SPECT/CT systems. In this paper we report on normal ranges for functional contribution of the individual lobes of the lung to overall function studied in the supine and erect positions in a small cohort of normal subjects. Differences are seen between the anatomical volumes as determined by segmentation of the CT scans and the ventilation and perfusion contributions in the different positions. As pulmonary function testing in the respiratory laboratory is usually performed in the upright position we perform all of our clinical imaging lung function studies in this position (for radiotracer administration) also. The methodology for measuring lobar function is minimally invasive, readily available, and would be hard to imagine being acquired as readily with any other technique., (Copyright © 2018. Published by Elsevier Inc.)