Chest
Clinical InvestigationsAirtrappingEffect of Heliox Breathing on Dynamic Hyperinflation in COPD Patients
Section snippets
MATERIALS AND METHODS
Twenty-two stable COPD patients (one woman) with a mean (± SE) age of 71 ± 1 years were studied. Patients had no other cardiopulmonary diseases, and had not experienced an upper respiratory tract infection during the previous month. No patient was being treated with oral β2-agonists, theophylline, or systemic corticosteroids, or had received inhaled short-acting β2-agonistic or anticholinergic drugs for 8 h or long-acting β2-agonists for 24 h before the study. The study was approved by the
RESULTS
Table 1 shows the anthropometric characteristics and baseline lung function data of seated patients, who were stratified according to the presence or absence of expiratory flow limitation while sitting. Only FEV1, FEV1/FVC ratio, and the midexpiratory phase of maximal mean expiratory flow were significantly lower in flow-limited patients. Among all of the respiratory variables studied, the only significant correlation of MRC score was with the IC percent predicted in flow-limited patients (r =
DISCUSSION
Our main findings are that in all COPD patients who were flow-limited while breathing air at rest, heliox had no effect on dynamic hyperinflation, independent of posture, while, in the same flow-limited patients, salbutamol significantly increased IC in both the sitting and the supine position.
In the present COPD population, there was a high prevalence (59%) of flow limitation during air breathing while in the sitting position. There are no previous reports on the correlation of IC and FEV1/FVC
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2022, Revue des Maladies RespiratoiresPlethysmographic assessment of tidal expiratory flow limitation
2022, Respiratory Physiology and NeurobiologyCitation Excerpt :Indeed, markedly higher Rexp/Rins and R2exp/Rins values must occur in the presence of tEFL, as it causes a selective increase of Rexp with respect to Rins, a discrepancy that is enhanced by the fact that the plethysmographic software provides the peak rather than the average values of intra-breath Rexp and Rins, and that in tEFL patients the width of the Palv-V̇ loop is markedly more pronounced in expiration than inspiration. The differences of routine spirometric and plethysmographic variables between tEFL and non-tEFL patients before bronchodilator administration (Table 1) as well as those caused by bronchodilator administration (Table 2) are in good agreement with the corresponding observations reported in previous studies (Koulouris et al., 1995; Eltayara et al., 1996; Diaz et al., 2001; Pecchiari et al., 2004; D’Angelo et al., 2009). Indeed, tEFL patients were characterized by higher ITGV, RV and airway resistance, hence lower IC and FEV1, as well as by a significant decrease of ITGV and RV with bronchodilator administration, which was not shared by non-tEFL patients.
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2011, Respiratory MedicineCitation Excerpt :These increases prevent dynamic airway closure during exhalation32). A greater maximal exhalation flow for a given lung volume will allow patients to sustain the same ventilation before and after administration of helium–oxygen but with a lower end-expiratory lung volume under the latter condition.33 The capacity to maintain the same ventilation with a lower end-expiratory lung volume with helium–oxygen can take place as long as expiratory flow-limitation is located in the central airways.33
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This study was supported by Ministero dell'Istruzione, dell'Università e della Ricerca Scientifica (MIUR), Rome, Italy.
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