Respiratory Physiology & Neurobiology最新文献

{"title":"Impact of posture and CPAP on nasal airflow","authors":"Ahmad T. Hamdan ,&nbsp;Sarin Rungmanee ,&nbsp;Nithita Sattaratpaijit ,&nbsp;Nader Shammout ,&nbsp;B. Tucker Woodson ,&nbsp;Guilherme J.M. Garcia","doi":"10.1016/j.resp.2024.104268","DOIUrl":"https://doi.org/10.1016/j.resp.2024.104268","url":null,"abstract":"<div><p>Obstructive sleep apnea (OSA) patients who use continuous positive airway pressure (CPAP) often complain of nasal dryness and nasal obstruction as side effects of CPAP. The physiological mechanisms by which CPAP may cause nasal dryness and nasal obstruction remain poorly understood. It has been hypothesized that CPAP interferes with the nasal cycle, abolishing the resting phase of the cycle and leading to nasal dryness. We performed rhinomanometry measurements in 31 OSA patients sitting, laid supine, and supine after 10 min of CPAP at 10 cmH₂O. A posture change from sitting to supine led to more symmetric airflow partitioning between the left and right nostrils in the supine position. CPAP did not have a significant impact on nasal resistance, unilateral airflows, or airflow partitioning. Our results suggest that airflow partitioning becomes more symmetric immediately after changing to a supine position, while CPAP had no effect on nasal airflow, thus preserving the nearly symmetric airflow partitioning achieved after the posture change.</p></div>","PeriodicalId":20961,"journal":{"name":"Respiratory Physiology & Neurobiology","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2024-04-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140816553","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Correlation of cervical-inspiratory-muscle electromyography and oxygen uptake during treadmill walking correlation of cervical-inspiratory-muscle electromyography and oxygen uptake","authors":"Kenta Kawamura ,&nbsp;Kazumichi Ae ,&nbsp;Rinri Uematsu ,&nbsp;Kazuto Yamaguchi ,&nbsp;Kazuhide Tomita","doi":"10.1016/j.resp.2024.104266","DOIUrl":"https://doi.org/10.1016/j.resp.2024.104266","url":null,"abstract":"<div><p>For measurements of exercise intensity, an individual's oxygen uptake (V̇O₂) is measured with an exhaled gas analyzer that involves a mask, but exercise coaching would benefit if an individual's V̇O₂ could be estimated with more easily obtained predictors. We investigated the predictability of V̇O₂ by electromyography (EMG) of the neck inspiratory muscles. We analyzed the EMG results of the sternocleidomastoid (EMGst) and scalene (EMGsc) muscles of 14 healthy adults who performed a treadmill exercise load test. Their V̇O₂, inspiratory flow rate, and heart rate were simultaneously recorded during the exercise. The exercise load test was performed twice at a ≥2-day interval. The first visit was an incremental exercise test, and the second was a repeated two-load exercise test at levels below and above the participant's ventilatory threshold (VT) as determined in the first test. We observed that the integrated EMG values for each exercise load showed partially significant positive correlations with the EMGst and EMGsc. However, the cervical inspiratory muscle EMGs did not show as high a correlation as the minute ventilation. These results indicate that (<em>i</em>) EMG of the cervical inspiratory muscles could be used to estimate V̇O₂, but (<em>ii</em>) these EMG parameters alone should be considered insufficient for estimating V̇O₂.</p></div>","PeriodicalId":20961,"journal":{"name":"Respiratory Physiology & Neurobiology","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2024-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140649271","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Airway stability in sleep apnea: Assessing continuous positive airway pressure efficiency","authors":"Suvash C. Saha ,&nbsp;Xinlei Huang ,&nbsp;Isabella Francis,&nbsp;Goutam Saha","doi":"10.1016/j.resp.2024.104265","DOIUrl":"https://doi.org/10.1016/j.resp.2024.104265","url":null,"abstract":"<div><p>Obstructive Sleep Apnea Syndrome (OSAS) disrupts millions of lives with its burden of airway obstruction during sleep. Continuous Positive Airway Pressure (CPAP) therapy has been scrutinized for its biomechanical impact on the respiratory tract. This study leverages computational fluid dynamics to investigate CPAP's effects at 9 cm H₂O (882.6 Pa) on the computed-tomography-based nasal-to-14-generation full respiratory tract model compared to ambient conditions, focusing on static pressure, airflow velocity, and shear stress. Our findings reveal that CPAP significantly increases static pressure, enhancing airway patency without adverse changes in airflow velocity or harmful shear stress on lung tissue, challenging prior concerns about its safety. Notably, the larynx experiences the highest shear stress due to its narrow anatomy, yet CPAP therapy overall supports airway walls against collapse. This investigation highlights CPAP's critical role in OSAS treatment, offering reassurance about its safety and efficacy. By clarifying CPAP therapy's physiological impacts, our study contributes vital insights for optimizing OSAS management strategies, affirming CPAP's benefit in maintaining open airways with minimal tissue strain.</p></div>","PeriodicalId":20961,"journal":{"name":"Respiratory Physiology & Neurobiology","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2024-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S1569904824000582/pdfft?md5=5cb9530c49f163cd56c74a778b8abb38&pid=1-s2.0-S1569904824000582-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140647019","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Sensitivity of the airway smooth muscle in terms of force, shortening and stiffness","authors":"Louis Gélinas,&nbsp;Andrés Rojas-Ruiz,&nbsp;Magali Boucher,&nbsp;Cyndi Henry,&nbsp;Ynuk Bossé","doi":"10.1016/j.resp.2024.104264","DOIUrl":"https://doi.org/10.1016/j.resp.2024.104264","url":null,"abstract":"<div><p>Eight pig tracheal strips were stimulated to contract with log increments of methacholine from 10^-8 to 10^-5 M. For each strip, the concentration-response was repeated four times in a randomized order to measure isometric force, isotonic shortening against a load corresponding to either 5 or 10 % of a reference force, and average force, stiffness, elastance and resistance over one cycle while the strip length was oscillating sinusoidally by 5 % at 0.2 Hz. For each readout, the logEC50 was calculated and compared. Isotonic shortening with a 5 % load had the lowest logEC50 (-7.13), yielding a greater sensitivity than any other contractile readout (p&lt;0.05). It was followed by isotonic shortening with a 10 % load (-6.66), elastance (-6.46), stiffness (-6.46), resistance (-6.38), isometric force (-6.32), and average force (-6.30). Some of these differences were significant. For example, the EC50 with the average force was 44 % greater than with the elastance (p=0.001). The methacholine sensitivity is thus affected by the contractile readout being measured.</p></div>","PeriodicalId":20961,"journal":{"name":"Respiratory Physiology & Neurobiology","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2024-04-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S1569904824000570/pdfft?md5=939eb67d802b05d3a7abebe3d7950765&pid=1-s2.0-S1569904824000570-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140546255","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Respiratory symptom perception during exercise in patients with heart failure with preserved ejection fraction","authors":"Josh T. Goh ,&nbsp;Bryce N. Balmain ,&nbsp;Andrew R. Tomlinson ,&nbsp;James P. MacNamara ,&nbsp;Satyam Sarma ,&nbsp;Thomas Ritz ,&nbsp;Denis J. Wakeham ,&nbsp;Tiffany L. Brazile ,&nbsp;Linda S. Hynan ,&nbsp;Benjamin D. Levine ,&nbsp;Tony G. Babb","doi":"10.1016/j.resp.2024.104256","DOIUrl":"https://doi.org/10.1016/j.resp.2024.104256","url":null,"abstract":"<div><p>We investigated whether central or peripheral limitations to oxygen uptake elicit different respiratory sensations and whether dyspnea on exertion (DOE) provokes unpleasantness and negative emotions in patients with heart failure with preserved ejection fraction (HFpEF). 48 patients were categorized based on their cardiac output (Q̇c)/oxygen uptake (V̇O₂) slope and stroke volume (SV) reserve during an incremental cycling test. 15 were classified as centrally limited and 33 were classified as peripherally limited. Ratings of perceived breathlessness (RPB) and unpleasantness (RPU) were assessed (Borg 0–10 scale) during a 20 W cycling test. 15 respiratory sensations statements (1–10 scale) and 5 negative emotions statements (1−10) were subsequently rated. RPB (Central: 3.5±2.0 vs. Peripheral: 3.4±2.0, p=0.86), respiratory sensations, or negative emotions were not different between groups (p&gt;0.05). RPB correlated (p&lt;0.05) with RPU (r=0.925), “anxious” (r=0.610), and “afraid” (r=0.383). While DOE provokes elevated levels of negative emotions, DOE and respiratory sensations seem more related to a common mechanism rather than central and/or peripheral limitations in HFpEF.</p></div>","PeriodicalId":20961,"journal":{"name":"Respiratory Physiology & Neurobiology","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2024-04-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140535287","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Mechanisms and consequences of excess exercise ventilation in fibrosing interstitial lung disease","authors":"Franciele Plachi ,&nbsp;Fernanda M. Balzan ,&nbsp;Ricardo Gass ,&nbsp;Kimberli D. Käfer ,&nbsp;Artur Z. Santos ,&nbsp;Marcelo B. Gazzana ,&nbsp;J.A. Neder ,&nbsp;Danilo C. Berton","doi":"10.1016/j.resp.2024.104255","DOIUrl":"10.1016/j.resp.2024.104255","url":null,"abstract":"<div><p>The causes and consequences of excess exercise ventilation (EEV) in patients with fibrosing interstitial lung disease (<em>f</em>-ILD) were explored. Twenty-eight adults with <em>f</em>-ILD and 13 controls performed an incremental cardiopulmonary exercise test. EEV was defined as ventilation-carbon dioxide output (⩒E-⩒CO₂) slope ≥36 L/L. Patients showed lower pulmonary function and exercise capacity compared to controls. Lower DL_CO was related to higher ⩒E-⩒CO₂ slope in patients (P&lt;0.05). 13/28 patients (46.4%) showed EEV, reporting higher dyspnea scores (P=0.033). Patients with EEV showed a higher dead space (VD)/tidal volume (VT) ratio while O₂ saturation dropped to a greater extent during exercise compared to those without EEV. Higher breathing frequency and VT/inspiratory capacity ratio were observed during exercise in the former group (P&lt;0.05). An exaggerated ventilatory response to exercise in patients with <em>f</em>-ILD is associated with a blunted decrease in the wasted ventilation in the physiological dead space and greater hypoxemia, prompting higher inspiratory constraints and breathlessness.</p></div>","PeriodicalId":20961,"journal":{"name":"Respiratory Physiology & Neurobiology","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2024-03-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140330103","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Tidal expiratory flow limitation during exercise is unrelated to peripheral hypercapnic chemosensitivity","authors":"Leah M. Mann ,&nbsp;Jason S. Chan ,&nbsp;Sarah A. Angus ,&nbsp;Connor J. Doherty ,&nbsp;Benjamin P. Thompson ,&nbsp;Glen E. Foster ,&nbsp;Paolo B. Dominelli","doi":"10.1016/j.resp.2024.104254","DOIUrl":"10.1016/j.resp.2024.104254","url":null,"abstract":"<div><p>We sought to determine if peripheral hypercapnic chemosensitivity is related to expiratory flow limitation (EFL) during exercise. Twenty participants completed one testing day which consisted of peripheral hypercapnic chemosensitivity testing and a maximal exercise test to exhaustion. The chemosensitivity testing consisting of two breaths of 10% CO₂ (O₂∼21%) repeated 5 times during seated rest and the first 2 exercise intensities during the maximal exercise test. Following chemosensitivity testing, participants continued cycling with the intensity increasing 20 W every 1.5 minutes till exhaustion. Maximal expiratory flow-volume curves were derived from forced expiratory capacity maneuvers performed before and after exercise at varying efforts. Inspiratory capacity maneuvers were performed during each exercise stage to determine EFL. There was no difference between the EFL and non-EFL hypercapnic chemoresponse (mean response during exercise 0.96 ± 0.46 and 0.91 ± 0.33 l min⁻¹ mmHg⁻¹, p=0.783). Peripheral hypercapnic chemosensitivity during mild exercise does not appear to be related to the development of EFL during exercise.</p></div>","PeriodicalId":20961,"journal":{"name":"Respiratory Physiology & Neurobiology","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2024-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140327076","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Extracellular acidification attenuates bronchial contraction via an autocrine activation of EP2 receptor: Its diminishment in murine experimental asthma","authors":"Yoshihiko Chiba ,&nbsp;Yamato Yamane ,&nbsp;Tsubasa Sato ,&nbsp;Wataru Suto ,&nbsp;Motohiko Hanazaki ,&nbsp;Hiroyasu Sakai","doi":"10.1016/j.resp.2024.104251","DOIUrl":"10.1016/j.resp.2024.104251","url":null,"abstract":"<div><h3>Purpose</h3><p>Extracellular acidification is a major component of tissue inflammation, including airway inflammation in asthmatics. However, its physiological/pathophysiological significance in bronchial function is not fully understood. Currently, the functional role of extracellular acidification on bronchial contraction was explored.</p></div><div><h3>Methods</h3><p>Left main bronchi were isolated from male BALB/c mice. Epithelium-removed tissues were exposed to acidic pH under submaximal contraction induced by 10⁻⁵ M acetylcholine in the presence or absence of a COX inhibitor indomethacin (10⁻⁶ M). Effects of AH6809 (10⁻⁶ M, an EP₂ receptor antagonist), BW A868C (10⁻⁷ M, a DP receptor antagonist) and CAY10441 (3×10⁻⁶ M, an IP receptor antagonist) on the acidification-induced change in tension were determined. The release of prostaglandin E₂ (PGE₂) from epithelium-denuded tissues in response to acidic pH was assessed using an ELISA.</p></div><div><h3>Results</h3><p>In the bronchi stimulated with acetylcholine, change in the extracellular pH from 7.4 to 6.8 caused a transient augmentation of contraction followed by a sustained relaxing response. The latter inhibitory response was abolished by indomethacin and AH6809 but not by BW A868C or CAY10441. Both indomethacin and AH6809 significantly increased potency and efficacy of acetylcholine at pH 6.8. Stimulation with low pH caused an increase in PGE₂ release from epithelium-denuded bronchi. Interestingly, the acidic pH-induced bronchial relaxation was significantly reduced in a murine asthma model that had a bronchial hyperresponsiveness to acetylcholine.</p></div><div><h3>Conclusion</h3><p>Taken together, extracellular acidification could inhibit the bronchial contraction <em>via</em> autocrine activation of EP₂ receptors. The diminished acidic pH-mediated inhibition of bronchial tone may contribute to excessive bronchoconstriction in inflamed airways such as asthma.</p></div>","PeriodicalId":20961,"journal":{"name":"Respiratory Physiology & Neurobiology","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2024-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140140634","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Analyzing key elements of breathing patterns, deriving remaining variables, and identifying cutoff values in individuals with chronic respiratory disease and healthy subjects","authors":"Ming-Lung Chuang","doi":"10.1016/j.resp.2024.104242","DOIUrl":"10.1016/j.resp.2024.104242","url":null,"abstract":"<div><h3>Background</h3><p>Pulmonary physiology encompasses intricate breathing patterns (BPs), characterized by breathing frequency (Bf), volumes, and flows. The complexities intensify in the presence of interstitial lung disease (ILD) and chronic obstructive pulmonary disease (COPD), especially during exercise. This study seeks to identify pivotal factors driving changes among these variables and establish cutoff values, comparing their efficacy in differentiating BPs to traditional methods, specifically a breathing reserve (BR) of 30% and a Bf of 50 bpm.</p></div><div><h3>Methods</h3><p>Screening 267 subjects revealed 23 with ILD, 126 with COPD, 33 healthy individuals, and the exclusion of 85 subjects. Lung function tests and ramp-pattern cardiopulmonary exercise testing (CPET) were conducted, identifying crucial BP elements. Changes were compared between groups at peak exercise. The area under the receiver operating characteristic curve (AUC) analysis determined cutoff values.</p></div><div><h3>Results</h3><p>Inspiratory time (TI) remained constant at peak exercise for all subjects (two-group comparisons, all p=NS). Given known differences in expiratory time (TE) and tidal volume (VT) among ILD, COPD, and healthy states, constant TI could infer patterns for Bf, total breathing cycle time (TTOT=60/Bf), I:E ratio, inspiratory duty cycle (IDC, TI/TTOT), rapid shallow breathing index (Bf/VT), tidal inspiratory and expiratory flows (VT/TI and VT/TE), and minute ventilation (V̇E=Bf×VT) across conditions. These inferences aligned with measurements, with potential type II errors causing inconsistencies. RSBI of 23 bpm/L and VT/TI of 104 L/min may differentiate ILD from control, while V̇E of 54 L/min, BR of 30%, and VT/TE of 108 may differentiate COPD from control. BR of 21%, TE of 0.99 s, and IDC of .45 may differentiate ILD from COPD. The algorithm outperformed traditional methods (AUC 0.84–0.91 versus 0.59–0.90).</p></div><div><h3>Conclusion</h3><p>The quasi-fixed TI, in conjunction with TE and VT, proves effective in inferring time-related variables of BPs. The findings have the potential to significantly enhance medical education in interpreting cardiopulmonary exercise testing. Moreover, the study introduces a novel algorithm for distinguishing BPs among individuals with ILD, COPD, and those who are healthy.</p></div>","PeriodicalId":20961,"journal":{"name":"Respiratory Physiology & Neurobiology","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2024-03-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140022524","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Using the gli spirographic prediction equations to revisit the allometric relationships between lung volumes, height and age in adults","authors":"Philippe Haouzi,&nbsp;Sairam Raghavan,&nbsp;Jonathan McCully","doi":"10.1016/j.resp.2024.104243","DOIUrl":"10.1016/j.resp.2024.104243","url":null,"abstract":"<div><p>The determination the forced vital capacity (FVC) and the forced expiratory volume in 1 second (FEV1) during spirometry studies, is at the core of the evaluation of the pulmonary function of patients with respiratory diseases. The Global Lung Function Initiative (GLI) offers the most extensive data set of normal lung functions available, which is currently used to determine the average expected/predicted FEV1 and FVC (_predV), and their lower limit of normal (LLN, 5th percentile) at any given height and age for women and men. These prediction equations are currently expressed in a rather complex form: _predV = <strong>exp [p+ (a x Ln (height) + (n x Ln (age)) + spline]</strong> and LLN = <strong>exp(Ln (</strong>_{<strong>pred</strong>}<strong>V) + Ln (1 – 1.645 x S x CV)/S)</strong>; and are currently used to generate interpretations in commercialized spinographic system. However, as shown in this paper, these equations contain physiological and fundamental allometric information on lung volumes that become obvious when rewriting mean predicted values as a “simple” power function of height and LLN as a percentage of the mean predicted values<em>.</em> We therefore propose to present the equations of prediction obtained from the GLI data using simplified expressions in adults (18–95 years old) to reveal some of their physiological and allometric meaning. Indeed, when predicted FEV1 and FVC (_predV) were expressed under the form _{<strong>pred</strong>}<strong>V= αx height</strong>^{<strong>a</strong>} <strong>x b(age),</strong> the resulting exponent (a) ranges between 2 and 3, transforming the one dimension of a length (size) into a <em>volume</em>, akin to the third-order power (cubic) function of height historically used to predict lung volumes. Only one function, b (age), is necessary to replace all the factors related to age, including the tables of discrete data of spline functions original equations. Similarly, LLN can be expressed as <strong>LLN = c (age) x</strong> _{<strong>pred</strong>}<strong>V</strong> to become a simple percentage of the predicted values, as a function of age. The equations with their respective new polynomial functions were validated in 52,764 consecutive spirometry tests performed in 2022 in 22,612 men and 30,152 women at the Cleveland Clinic. Using these equations, it become obvious that for both women and men, FEV1/FVC ratio decreases with the size as the exponent of the power function of height is lower for FEV1 than FVC. We conclude that rewriting the GLI predicted equations with simpler formulations restitutes to the GLI data some of their original allometric meaning, without altering the accuracy of their prediction.</p></div>","PeriodicalId":20961,"journal":{"name":"Respiratory Physiology & Neurobiology","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2024-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140022525","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}