Effects of continuous positive airway pressure on pulmonary function and exercise tolerance in patients with congestive heart failure.

STUDY OBJECTIVES

Continuous positive airway pressure (CPAP) has been used to improve cardiopulmonary function and reduce pulmonary edema symptoms in patients with congestive heart failure (CHF). The objective of this study was to evaluate the efficacy of CPAP therapy on pulmonary function and exercise tolerance in patients with CHF.

DESIGN

Prospective blind randomized clinical study.

PARTICIPANTS

Twenty-four patients with class II or III CHF and dilated cardiomyopathy were randomly assigned to 30 min of CPAP therapy and respiratory exercises (CPAP group) or respiratory exercise only (control group) once a day for 14 days.

MEASUREMENTS AND RESULTS

Evaluation of pulmonary function was performed measuring FEV1 and FVC. Exercise tolerance was assessed measuring the distance walked during the 6-min walking test (6MWT). These parameters were measured before treatment and 4 days, 9 days, and 14 days later. CPAP therapy caused a progressive increase (p < 0.05) in both FVC (maximum of 16% after 9 days) and FEV1 (maximum of 14% after 14 days) compared to basal values, without significant changes in the control group. The 6MWT showed a progressive improvement in the distance walked in the CPAP group, reaching approximately 28% above the basal values in the CPAP group and without significant changes in the control group.

CONCLUSIONS

These data show that the use of CPAP therapy for 2 weeks on a daily basis is able to enhance pulmonary function and consequently improve the tolerance to physical activities in patients with CHF. The clinical implication of this finding is that CPAP therapy could potentially be used as an adjunct to the treatment of CHF patients.