title: Use of continuous positive airway pressure reduces airway reactivity in adults with asthma.
abstract: Asthma is characterised by airway hyperreactivity, which is primarily treated with β-adrenergic bronchodilators and anti-inflammatory agents. However, mechanical strain during breathing is an important modulator of airway responsiveness and we have previously demonstrated in animal models that continuous positive airway pressure (CPAP) resulted in lower in vivo airway reactivity. We now evaluated whether using nocturnal CPAP decreased airway reactivity in clinically-stable adults with asthma. Adults with stable asthma and normal spirometry used nocturnal CPAP (8-10 cmH(2)O) or sham treatment (0-2 cmH(2)O) for 7 days. Spirometry and bronchial challenges were obtained before and after treatment. The primary outcome was the provocative concentration of methacholine causing a 20% fall in forced expiratory volume in 1 s (PC(20)). The CPAP group (n=16) had a significant decrease in airway reactivity (change in (Δ)logPC(20) 0.406, p<0.0017) while the sham group (n=9) had no significant change in airway reactivity (ΔlogPC(20) 0.003, p=0.9850). There was a significant difference in the change in airway reactivity for the CPAP versus the sham group (ΔlogPC(20) 0.41, p<0.043). Our findings indicate that chronic mechanical strain of the lungs produced using nocturnal CPAP for 7 days reduced airway reactivity in clinically stable asthmatics. Future studies of longer duration are required to determine whether CPAP can also decrease asthma symptoms and/or medication usage.
authors: Division of Pulmonary, Allergy, Critical Care, Occupational, and Sleep Medicine, Indiana University School of Medicine, Indianapolis, IN, USA.
authors: Michael
authors: M
authors: Busk
authors: Nancy
authors: N
authors: Busk
authors: Paula
authors: P
authors: Puntenney
authors: Janet
authors: J
authors: Hutchins
authors: Zhangsheng
authors: Z
authors: Yu
authors: Susan J
authors: SJ
authors: Gunst
authors: Robert S
authors: RS
authors: Tepper
mesh_terms: D000328:Adult; D001249:Asthma / Q000503:physiopathology / Q000628:therapy*; D001985:Bronchial Provocation Tests / Q000379:methods*; D001993:Bronchodilator Agents; D045422:Continuous Positive Airway Pressure / Q000379:methods*; D005260:Female; D005541:Forced Expiratory Volume / Q000187:drug effects; D006801:Humans; D008168:Lung / Q000473:pathology*; D008297:Male; D016210:Methacholine Chloride / Q000494:pharmacology; D009569:Nitric Oxide / Q000378:metabolism; D012129:Respiratory Function Tests; D013147:Spirometry / Q000379:methods; D013314:Stress, Mechanical; D013997:Time Factors; D016896:Treatment Outcome
chemical_list: D001993:Bronchodilator Agents; D016210:Methacholine Chloride; D009569:Nitric Oxide