EFFECT OF OXYGEN ON SLEEP QUALITY, COGNITIVE FUNCTION AND SYMPATHETICACTIVITY IN PATIENTS WITH CHRONIC HEART-FAILURE AND CHEYNE-STOKES RESPIRATION

Background Cheyne-Stokes respiration disrupts sleep, leading to daytim e somnolence and cognitive impairment. It is also an independent marke r of increased mortality in heart failure. This study evaluated the ef fectiveness of oxygen therapy for Cheyne-Stokes respiration in heart f ailure. Methods Eleven patients with stable heart failure and Cheyne-S tokes breathing were studied. Oxygen and air were administered for 4 w eeks in a double-blind, cross-over study. Sleep and disordered breathi ng was assessed by polysomnography. Symptoms were assessed using the E pworth Sleepiness Scale, visual analogue and quality of life scores. C ognitive function was assessed by neuro-psychometric testing. Overnigh t urinary catecholamine excretion was used as a measure of sympathetic nerve activity. Results Ninety-seven percent of apnoeas were central in origin. Oxygen therapy reduced the central apnoea rate (18.4+/-4.1 vs 3.8+/-2.1 per hour; P=0.05) and periodic breathing time (33.6+/-7.4 vs 10.7+/-3.9% of actual sleep time; P=0.003). Oxygen did not improve sleep quality, patient symptoms or cognitive failure. Oxygen reduced urinary noradrenaline excretion (8.3+/-1.5 vs 4.1 +/- 0.6 nmol. mmol(- 1) urinary creatinine; P=0.03). Conclusion Oxygen stabilized sleep dis ordered breathing and reduced sympathetic activity in patients with he art failure and Cheyne-Stokes respiration. We were unable to demonstra te an effect on either patient symptoms or cognitive function.