Abstract:
RATIONALE:Breathing supplemental oxygen reduces breathlessness during exercise in patients with chronic obstructive pulmonary disease (COPD). Replacing nitrogen with helium reduces expiratory flow resistance and may improve lung emptying. Combining these treatments should be independently effective. OBJECTIVES:Study the effect of changing oxygen or helium concentration in inspired gas during exercise in patients with stable COPD. METHODS:In 82 patients (mean age, 69.7 yr; mean FEV(1), 42.6% predicted), we measured endurance shuttle walking distance, resting and exercise oxygen saturation, and end-exercise dyspnea (Borg scale) while patients breathed Heliox28 (72% He/28% O(2)), Heliox21 (79% He/21% O(2)), Oxygen28 (72% N(2)/28% O(2)), or medical air (79% N(2)/21% O(2)). Gases were administered using a randomized, blinded, crossover design via a face mask and an inspiratory demand valve. RESULTS:Breathing Heliox28 increased walking distance (mean+/-SD, 147+/-150 m) and reduced Borg score (-1.28+/-1.30) more than any other gas mixture. Heliox21 significantly increased walking distance (99+/-101 m) and reduced dyspnea (Borg score, -0.76+/-0.77) compared with medical air. These changes were similar to those breathing Oxygen28. The effects of helium and oxygen in Heliox28 were independent. The increase in walking distance while breathing Heliox28 was inversely related to baseline FEV(1) breathing air. CONCLUSION:Reducing inspired gas density can improve exercise performance in COPD as much as increasing inspired oxygen. These effects can be combined as Heliox28 and are most evident in patients with more severe airflow obstruction.
journal_name
Am J Respir Crit Care Medauthors
Laude EA,Duffy NC,Baveystock C,Dougill B,Campbell MJ,Lawson R,Jones PW,Calverley PMdoi
10.1164/rccm.200506-925OCkeywords:
subject
Has Abstractpub_date
2006-04-15 00:00:00pages
865-70issue
8eissn
1073-449Xissn
1535-4970pii
200506-925OCjournal_volume
173pub_type
杂志文章,随机对照试验abstract::Premature lungs are highly susceptible to lung injuries, leading to bronchopulmonary dysplasia (BPD). Keratinocyte growth factor (KGF) is produced by the developing lung and may reduce the risk of BPD by preventing injury to the lung epithelium and enhancing its repair. To determine whether KGF concentrations in the a...
journal_title:American journal of respiratory and critical care medicine
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journal_title:American journal of respiratory and critical care medicine
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journal_title:American journal of respiratory and critical care medicine
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更新日期:2001-06-01 00:00:00