Helium–oxygen ventilation in the presence of expiratory flow-limitation: A model study

Brighenti, Chiara; Barbini, Paolo; Gnudi, Gianni; Cevenini, Gabriele; Pecchiari, Matteo; D’Angelo, Edgardo

doi:10.1016/j.resp.2006.12.012

Cited by 19 publications

(18 citation statements)

References 34 publications

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“…It is located beyond the seventh (i.e. from the eighth onwards) generation during tidal breathing [2][3][4][5].…”

mentioning

confidence: 99%

“…Initially, the latter is histologically characterised by denuded epithelium, rupture of alveolar airway attachments, and increased number of polymorphonuclear leukocytes [6][7][8]. Studies in which heliox (80% He/20% O 2 ) was administered in COPD and chronic heart failure patients also provided corroborative evidence that EFLT was located in the peripheral airways [2][3][4][5]. EFLT promotes dynamic pulmonary hyperinflation and intrinsic positive end-expiratory pressure (PEEPi) with concurrent dyspnoea and exercise limitation [9].…”

mentioning

confidence: 99%

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Physiological techniques for detecting expiratory flow limitation during tidal breathing

Koulouris¹,

Hardavella²

2011

Eur Respir Rev

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Patients with severe chronic obstructive pulmonary disease (COPD) often exhale along the same flow-volume curve during quiet breathing as they do during the forced expiratory vital capacity manoeuvre, and this has been taken as an indicator of expiratory flow limitation at rest (EFLT). Therefore, EFLT, namely attainment of maximal expiratory flow during tidal expiration, occurs when an increase in transpulmonary pressure causes no increase in expiratory flow. EFLT leads to small airway injury and promotes dynamic pulmonary hyperinflation, with concurrent dyspnoea and exercise limitation. In fact, EFLT occurs commonly in COPD patients (mainly in Global Initiative for Chronic Obstructive Lung Disease III and IV stage), in whom the latter symptoms are common, but is not exclusive to COPD, since it can also be detected in other pulmonary and nonpulmonary diseases like asthma, acute respiratory distress syndrome, heart failure and obesity, etc. The existing up to date physiological techniques of assessing EFLT are reviewed in the present work. Among the currently available techniques, the negative expiratory pressure has been validated in a wide variety of settings and disorders. Consequently, it should be regarded as a simple, noninvasive, practical and accurate new technique.

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“…It is located beyond the seventh (i.e. from the eighth onwards) generation during tidal breathing [2][3][4][5].…”

mentioning

confidence: 99%

mentioning

confidence: 99%

Physiological techniques for detecting expiratory flow limitation during tidal breathing

Koulouris¹,

Hardavella²

2011

Eur Respir Rev

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“…The resistive inspiratory work may also have been reduced [34,35]. In fact, the potential for helium to improve expiratory flow limitation increases with disease severity and with higher flow rates [34], i.e. the precise conditions found in the present study.…”

Section: Discussionmentioning

confidence: 50%

“…It is noteworthy that resting physiological variables were poorly predictive of changes in Tlim with HeHOx. Previous studies have suggested that any benefit from HeHOx would be particularly observed in patients with more central airflow limitation [13,34,35], which would allow them to maintain the same ventilation (or even higher, as in the present study) with a lower EELV. In practical terms, however, our data suggest that if HeHOX is to be used as an ergogenic aid in advanced COPD under LTOT its positive effects should be unequivocally demonstrated in individual patients.…”

Section: Discussionmentioning

confidence: 51%

“…It is legitimate to assume that the deflating effects of helium coupled with the lower pressure to overcome frictional resistance [13] may have summed up with the lower ventilatory drive induced by HOx [3,4] to diminish the elastic and the resistive work of breathing [6]. The resistive inspiratory work may also have been reduced [34,35]. In fact, the potential for helium to improve expiratory flow limitation increases with disease severity and with higher flow rates [34], i.e.…”

Section: Discussionmentioning

confidence: 99%

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Exercise tolerance with helium-hyperoxiaversushyperoxia in hypoxaemic patients with COPD

et al. 2012

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The purpose of this study was to investigate whether helium-hyperoxia (HeHOx) would allow greater tolerance to maximal and submaximal exercise compared to hyperoxia (HOx) on isolation in hypoxaemic chronic obstructive pulmonary disease (COPD) patients under long-term oxygen therapy.In a double-blind study, 24 males in the Global Initiative for Chronic Obstructive Lung Disease functional class IV (forced expiratory volume in 1 s 35.2¡10.1% predicted and arterial oxygen tension 56.2¡7.5 mmHg) were submitted to incremental and constant load cycling at 70-80% peak work rate while breathing HOx (60% nitrogen and 40% oxygen) or HeHOx (60% helium and 40% oxygen).HeHOx improved resting airflow obstruction and lung hyperinflation in all but two patients (p,0.05). Peak work rate and time to exercise intolerance were higher with HeHOx than HOx in 17 (70.8%) out of 24 patients and 14 (66.6%) out of 21 patients, respectively (p,0.05). End-expiratory lung volumes were lower with HeHOx, despite a higher ventilatory response (p,0.05). HeHOx speeded on-exercise oxygen uptake kinetics by ,30%, especially in more disabled and hyperinflated patients. Fat-free mass was the only independent predictor of higher peak work rate with HeHOx (r 2 50.66, p,0.001); in contrast, none of the resting characteristics or exercise responses were related to improvements in time to exercise intolerance (p.0.05).Helium is a valuable ergogenic aid when added to HOx for most long-term oxygen therapy-dependent patients with advanced COPD. @ERSpublications Helium is a valuable ergogenic aid when added to hyperoxia for most advanced COPD patients on long-term oxygen therapy

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Respiratory Mechanics

Miserocchi

2023

Perspectives in Physiology

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Helium–oxygen ventilation in the presence of expiratory flow-limitation: A model study

Cited by 19 publications

References 34 publications

Physiological techniques for detecting expiratory flow limitation during tidal breathing

Physiological techniques for detecting expiratory flow limitation during tidal breathing

Exercise tolerance with helium-hyperoxiaversushyperoxia in hypoxaemic patients with COPD

Respiratory Mechanics

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