Objective: To examine the effect of oxygen on apneas and sleep quality in patients with frequent central apneas during sleep.
Design/subjects: Prospective intervention study of 20 consecutive patients with predominant central apnea identified from 570 patients referred for suspected sleep apnea syndrome. Sixteen patients had congestive heart failure and seven of them had a previous stroke. Three of the remaining four patients without heart failure had experienced a previous stroke, and one was being treated with morphine.
Setting: The Department of Pulmonary Medicine at Umeå (Sweden) University Hospital.
Interventions: The patients were investigated for one night receiving nasal oxygen and one night without it.
Measurements: Overnight polysomnography with transcutaneous PCO2 and arterial blood gases.
Results: Central apneas occurred during Cheyne-Stokes respiration in 18 of 20 patients and two patients had idiopathic central apneas. Without oxygen, the median number of all central apneas and hypopneas was 33.5 (range, 8.0 to 52.0) per hour of sleep. These episodes decreased to 5.0 (range, 0.0 to 31.0)(p < 0.01) during oxygen therapy. In 17 of 20 patients, the frequency of central apneas was reduced by more than 50%. Central apneas were reduced by oxygen irrespective of the presence or absence of heart failure or Cheyne-Stokes respiration. The arousal frequency was reduced during oxygen treatment. Daytime sleepiness, difficulty falling asleep, snoring, and self-scored awakenings were reduced in seven patients who were given nocturnal oxygen at home. Obstructive and mixed apneas were unaffected by oxygen.
Conclusions: Oxygen effectively reduces central sleep apnea in eucapnic patients.