Patients with
congestive heart failure and
Cheyne-Stokes respiration have a low arterial oxygen saturation, especially during sleep, which can be increased by breathing
oxygen. Chronic alterations in blood
gases are known to modulate the hypercapnic ventilatory response (HCVR). We therefore evaluated whether the HCVR is influenced by nocturnal nasal
oxygen in patients with
heart failure and
Cheyne-Stokes respiration. Twenty patients with chronic
congestive heart failure and a left ventricular ejection fraction < or = 35% (mean 18.3% +/- SD 6.0%) as well as 25 healthy control subjects were studied. The patients were assigned to 1 week each of nocturnal nasal
oxygen and room air with a flow of 41 min-1 in a randomized cross-over fashion. After each week resting ventilation and HCVR were evaluated by the rebreathing technique. Breathing
oxygen during the night for 1 week increased the basal nocturnal oxygen saturation from 92.5% +/- 1.6% to 96.5% +/- 0.9% (P < 0.000,01) and reduced
Cheyne-Stokes respiration. HCVR was 1.22 +/- 0.90 l min-1 mmHg-1 after nocturnal room air and did not differ from that in the control subjects (1.31 +/- 0.62 l min-1 mmHg-1). In the patients HCVR decreased to 0.91 +/- 0.52 l min-1 mmHg-1 after nocturnal
oxygen (P = 0.019). There were no significant changes with nocturnal
oxygen in resting minute ventilation, respiratory rate or end-tidal PCO2. We conclude that nocturnal nasal
oxygen reduces HCVR in patients with
congestive heart failure and
Cheyne-Stokes respiration.