Effects of increasing tidal volume and end-expiratory lung volume on induced bronchoconstriction in healthy humans.

IF 5.8 2区 医学 Q1 Medicine
Alessandro Gobbi, Andrea Antonelli, Raffaele Dellaca, Giulia M Pellegrino, Riccardo Pellegrino, Jeffrey J Fredberg, Julian Solway, Vito Brusasco
{"title":"Effects of increasing tidal volume and end-expiratory lung volume on induced bronchoconstriction in healthy humans.","authors":"Alessandro Gobbi, Andrea Antonelli, Raffaele Dellaca, Giulia M Pellegrino, Riccardo Pellegrino, Jeffrey J Fredberg, Julian Solway, Vito Brusasco","doi":"10.1186/s12931-024-02909-9","DOIUrl":null,"url":null,"abstract":"<p><strong>Background: </strong>Increasing functional residual capacity (FRC) or tidal volume (V<sub>T</sub>) reduces airway resistance and attenuates the response to bronchoconstrictor stimuli in animals and humans. What is unknown is which one of the above mechanisms is more effective in modulating airway caliber and whether their combination yields additive or synergistic effects. To address this question, we investigated the effects of increased FRC and increased V<sub>T</sub> in attenuating the bronchoconstriction induced by inhaled methacholine (MCh) in healthy humans.</p><p><strong>Methods: </strong>Nineteen healthy volunteers were challenged with a single-dose of MCh and forced oscillation was used to measure inspiratory resistance at 5 and 19 Hz (R<sub>5</sub> and R<sub>19</sub>), their difference (R<sub>5-19</sub>), and reactance at 5 Hz (X<sub>5</sub>) during spontaneous breathing and during imposed breathing patterns with increased FRC, or V<sub>T</sub>, or both. Importantly, in our experimental design we held the product of V<sub>T</sub> and breathing frequency (BF), i.e, minute ventilation (V<sub>E</sub>) fixed so as to better isolate the effects of changes in V<sub>T</sub> alone.</p><p><strong>Results: </strong>Tripling V<sub>T</sub> from baseline FRC significantly attenuated the effects of MCh on R<sub>5</sub>, R<sub>19</sub>, R<sub>5-19</sub> and X<sub>5</sub>. Doubling V<sub>T</sub> while halving BF had insignificant effects. Increasing FRC by either one or two V<sub>T</sub> significantly attenuated the effects of MCh on R<sub>5,</sub> R<sub>19</sub>, R<sub>5-19</sub> and X<sub>5</sub>. Increasing both V<sub>T</sub> and FRC had additive effects on R<sub>5</sub>, R<sub>19</sub>, R<sub>5-19</sub> and X<sub>5</sub>, but the effect of increasing FRC was more consistent than increasing V<sub>T</sub> thus suggesting larger bronchodilation. When compared at iso-volume, there were no differences among breathing patterns with the exception of when V<sub>T</sub> was three times larger than during spontaneous breathing.</p><p><strong>Conclusions: </strong>These data show that increasing FRC and V<sub>T</sub> can attenuate induced bronchoconstriction in healthy humans by additive effects that are mainly related to an increase of mean operational lung volume. We suggest that static stretching as with increasing FRC is more effective than tidal stretching at constant V<sub>E</sub>, possibly through a combination of effects on airway geometry and airway smooth muscle dynamics.</p>","PeriodicalId":49131,"journal":{"name":"Respiratory Research","volume":null,"pages":null},"PeriodicalIF":5.8000,"publicationDate":"2024-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11304934/pdf/","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Respiratory Research","FirstCategoryId":"3","ListUrlMain":"https://doi.org/10.1186/s12931-024-02909-9","RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"Medicine","Score":null,"Total":0}
引用次数: 0

Abstract

Background: Increasing functional residual capacity (FRC) or tidal volume (VT) reduces airway resistance and attenuates the response to bronchoconstrictor stimuli in animals and humans. What is unknown is which one of the above mechanisms is more effective in modulating airway caliber and whether their combination yields additive or synergistic effects. To address this question, we investigated the effects of increased FRC and increased VT in attenuating the bronchoconstriction induced by inhaled methacholine (MCh) in healthy humans.

Methods: Nineteen healthy volunteers were challenged with a single-dose of MCh and forced oscillation was used to measure inspiratory resistance at 5 and 19 Hz (R5 and R19), their difference (R5-19), and reactance at 5 Hz (X5) during spontaneous breathing and during imposed breathing patterns with increased FRC, or VT, or both. Importantly, in our experimental design we held the product of VT and breathing frequency (BF), i.e, minute ventilation (VE) fixed so as to better isolate the effects of changes in VT alone.

Results: Tripling VT from baseline FRC significantly attenuated the effects of MCh on R5, R19, R5-19 and X5. Doubling VT while halving BF had insignificant effects. Increasing FRC by either one or two VT significantly attenuated the effects of MCh on R5, R19, R5-19 and X5. Increasing both VT and FRC had additive effects on R5, R19, R5-19 and X5, but the effect of increasing FRC was more consistent than increasing VT thus suggesting larger bronchodilation. When compared at iso-volume, there were no differences among breathing patterns with the exception of when VT was three times larger than during spontaneous breathing.

Conclusions: These data show that increasing FRC and VT can attenuate induced bronchoconstriction in healthy humans by additive effects that are mainly related to an increase of mean operational lung volume. We suggest that static stretching as with increasing FRC is more effective than tidal stretching at constant VE, possibly through a combination of effects on airway geometry and airway smooth muscle dynamics.

增加潮气量和呼气末肺活量对健康人诱发支气管收缩的影响。
背景:在动物和人类中,增加功能残余容量(FRC)或潮气量(VT)可降低气道阻力,减轻对支气管收缩刺激物的反应。目前尚不清楚的是,上述机制中哪一种在调节气道口径方面更有效,以及两者结合是否会产生相加或协同效应。为了解决这个问题,我们研究了增加 FRC 和增加 VT 对减轻健康人吸入甲氧胆碱(MCh)引起的支气管收缩的影响:19 名健康志愿者接受了单剂量 MCh 的挑战,并使用强迫振荡法测量了自主呼吸时的 5 赫兹和 19 赫兹吸气阻力(R5 和 R19)、它们的差值(R5-19)以及 5 赫兹的电抗(X5),还测量了强加的 FRC 或 VT 增加或两者同时增加的呼吸模式。重要的是,在我们的实验设计中,我们将 VT 与呼吸频率(BF)的乘积(即分钟通气量(VE))保持不变,以便更好地隔离 VT 单独变化的影响:结果:将 VT 在基线 FRC 的基础上增加三倍,可明显减弱 MCh 对 R5、R19、R5-19 和 X5 的影响。将 VT 增加一倍,同时将 BF 减半的效果不明显。增加一个或两个 VT 的 FRC 可明显减弱 MCh 对 R5、R19、R5-19 和 X5 的影响。增加 VT 和 FRC 对 R5、R19、R5-19 和 X5 有叠加效应,但增加 FRC 的效应比增加 VT 更一致,这表明支气管扩张作用更大。在等容积条件下进行比较时,除了 VT 比自主呼吸时大三倍外,其他呼吸模式之间没有差异:这些数据表明,增加 FRC 和 VT 可通过相加效应减轻健康人的诱导性支气管收缩,而这种效应主要与平均肺活量的增加有关。我们认为,在 VE 保持不变的情况下,静态拉伸和增加 FRC 比潮汐拉伸更有效,这可能是通过对气道几何形状和气道平滑肌动力学的综合影响实现的。
本文章由计算机程序翻译,如有差异,请以英文原文为准。
求助全文
约1分钟内获得全文 求助全文
来源期刊
Respiratory Research
Respiratory Research RESPIRATORY SYSTEM-
CiteScore
9.70
自引率
1.70%
发文量
314
审稿时长
4-8 weeks
期刊介绍: Respiratory Research publishes high-quality clinical and basic research, review and commentary articles on all aspects of respiratory medicine and related diseases. As the leading fully open access journal in the field, Respiratory Research provides an essential resource for pulmonologists, allergists, immunologists and other physicians, researchers, healthcare workers and medical students with worldwide dissemination of articles resulting in high visibility and generating international discussion. Topics of specific interest include asthma, chronic obstructive pulmonary disease, cystic fibrosis, genetics, infectious diseases, interstitial lung diseases, lung development, lung tumors, occupational and environmental factors, pulmonary circulation, pulmonary pharmacology and therapeutics, respiratory immunology, respiratory physiology, and sleep-related respiratory problems.
×
引用
GB/T 7714-2015
复制
MLA
复制
APA
复制
导出至
BibTeX EndNote RefMan NoteFirst NoteExpress
×
提示
您的信息不完整,为了账户安全,请先补充。
现在去补充
×
提示
您因"违规操作"
具体请查看互助需知
我知道了
×
提示
确定
请完成安全验证×
copy
已复制链接
快去分享给好友吧!
我知道了
右上角分享
点击右上角分享
0
联系我们:info@booksci.cn Book学术提供免费学术资源搜索服务,方便国内外学者检索中英文文献。致力于提供最便捷和优质的服务体验。 Copyright © 2023 布克学术 All rights reserved.
京ICP备2023020795号-1
ghs 京公网安备 11010802042870号
Book学术文献互助
Book学术文献互助群
群 号:481959085
Book学术官方微信