Improvement of exercise capacity with treatment of Cheyne-Stokes respiration in patients with congestive heart failure

Objectives. The aim of this study was to determine the impact of nasal nocturnal oxygen therapy on respiration, sleep, exercise capacity, cognitive function and daytime symptoms in patients with congestive heart failure and Cheyne-Stokes respiration. Background. Cheyne-Stokes respiration is common in patients with congestive heart failure and is associated with significant nocturnal oxygen desaturation and sleep disruption with arousals. Oxygen desaturations and arousals cause an increase in pulmonary artery pressure and sympathoneural activity and therefore may reduce exercise capacity. Oxygen is an effective treatment of Cheyne-Stokes respiration and should improve exercise capacity in these patients. Methods. The study was designed as a randomized, crossover, double-blind, placebo-controlled trial: 22 patients were assigned to 1 week each of nocturnal oxygen and room air. After each week polysomnography, maximal bicycle exercise with expiratory gas analysis and trail making test were performed, and a health assessment chart was completed. Results. Nocturnal oxygen significantly reduced the duration of Cheyne-Stokes respiration (162 +/- 142 vs. 88 +/- 105 min [mean +/- SD]; p < 0.005). Sleep improved as evidenced by less stage 1 sleep and fewer arousals (20 +/- 13 vs. 15 +/- 9/h total sleep time; p < 0.05) as well as more stage 2 and slow-wave sleep; nocturnal oxygen saturation also improved. Peak oxygen consumption during exercise testing increased after oxygen treatment (835 +/- 395 vs. 960 +/- 389 ml/min; p < 0.05). Cognitive function evaluated by the trail-making test improved, but daytime symptoms in the health assessment chart did not improve significantly. Conclusions. Successful treatment of Cheyne-Stokes respiration with nocturnal nasal oxygen improves not only sleep, but also exercise tolerance and cognitive function in patients with congestive heart failure.