Central sleep apnea treated by a constant low dose of CO2 supplied by a novel device

CO inhalation has been previously reported as a treatment for central sleep apnea both when associated with heart failure or where the cause is unknown. Here we evaluated a novel CO supply system using a novel open mask capable of comfortably delivering a constantly inspired fraction of CO (FiCO) during sleep. We recruited eighteen patients with central sleep apnea (13 patients with cardiac disease, and 5 patients idiopathic) diagnosed by diaphragm EMG recordings made during overnight full polysomnography (Night 1). In each case the optimal FiCO was determined by an overnight manual titration with PSG (Night 2). Titration commenced at 1% CO and increased by 0.2% increments until CSA disappeared. Patients were then treated on the third night (Night 3) with the lowest therapeutically effective concentration of CO derived from night 2. Comparing night 1 and night 3, both AHI (31±14 vs. 6±3 events/h, p<0.01) and arousal index (22±8 vs. 15±8 events/h, p<0.01) were significantly improved during CO treatment. Sleep efficiency improved from 71±18 to 80±11%, p<0.05, and sleep latency was shorter (23±18 vs. 10±10 min, p<0.01). Heart rate was not different between night 1 and night 3. Our data confirm the feasibility of our CO delivery system and indicate that individually titrated CO supplementation with a novel device including a special open mask can reduce sleep disordered breathing severity and improve sleep quality. Randomized controlled studies should now be undertaken to assess therapeutic benefit for patients with CSA.