title: The effect of oxygen on respiration and sleep in patients with congestive heart failure.
abstract: OBJECTIVE
  To determine the effect of supplemental oxygen on Cheyne-Stokes respiration, nocturnal oxygen saturation (SaO2), and sleep in male patients with severe, stable congestive heart failure.
  
  
  METHODS
  Randomized, single-blind, placebo-controlled crossover study.
  
  
  METHODS
  Patients referred from outpatient cardiology clinics of two teaching hospitals.
  
  
  METHODS
  Sequential sample of nine outpatients with severe, stable congestive heart failure.
  
  
  METHODS
  For each patient, sleep studies (after an adaptation night) from two consecutive randomized nights were compared; one study was done while the patient breathed compressed air and the other while the patient breathed oxygen (O2). Compressed air and oxygen were both administered through nasal cannulae at 2 to 3 L/min.
  
  
  RESULTS
  Cheyne-Stokes respiration, defined as periodic breathing with apnea or hypopnea, was found in all patients. Low-flow oxygen significantly reduced the duration of Cheyne-Stokes respiration (50.7% +/- 12.0% to 24.2% +/- 5.4% total sleep time), mainly during stage 1 NREM (non-rapid eye movement) sleep (21.3% +/- 7.1% to 6.7% +/- 2.3% total sleep time) with no significant change during stage 2 sleep, slow-wave sleep, or REM (rapid eye movement) sleep. Although patients had normal SaO2 (96.0% +/- 1.7%) while awake, severe sleep hypoxemia was common; breathing oxygen reduced the amount of time that SaO2 was less than 90% from 22.3% +/- 8.0% to 2.41% +/- 1.93% of total sleep time. Sleep, disrupted to a variable extent in all patients, improved with oxygen therapy: There was an increase in total sleep time from 275.3 min +/- 36.6 to 324.6 min +/- 23.3; a reduction in the proportion of stage 1 sleep (27.6% +/- 5.8% total sleep time to 15.2% +/- 2.6% total sleep time); and a reduction in the number of arousals (30.4/h +/- 8.0 to 13.8/h +/- 1.9). The apnea-hypopnea index was reduced from 30.0 +/- 4.7 to 18.9 +/- 2.4 with oxygen breathing.
  
  
  CONCLUSIONS
  In severe, stable congestive heart failure, nocturnal oxygen therapy reduces Cheyne-Stokes respiration, corrects hypoxemia, and consolidates sleep by reducing arousals caused by the hyperpneic phase of Cheyne-Stokes respiration. Correction of nocturnal hypoxemia and sleep disruption may improve the clinical status of these patients.
authors.affiliation: University of Manitoba, Winnipeg, Manitoba, Canada.
authors.forename: P J
authors.initials: PJ
authors.lastname: Hanly
authors.forename: T W
authors.initials: TW
authors.lastname: Millar
authors.forename: D G
authors.initials: DG
authors.lastname: Steljes
authors.forename: R
authors.initials: R
authors.lastname: Baert
authors.forename: M A
authors.initials: MA
authors.lastname: Frais
authors.forename: M H
authors.initials: MH
authors.lastname: Kryger
mesh_terms: D000328:Adult; D000368:Aged; D001143:Arousal / Q000187:drug effects; D002639:Cheyne-Stokes Respiration / Q000209:etiology / Q000628:therapy*; D006333:Heart Failure / Q000150:complications / Q000628:therapy*; D006801:Humans; D000860:Hypoxia / Q000209:etiology / Q000628:therapy; D008297:Male; D008875:Middle Aged; D010102:Oxygen Inhalation Therapy; D011897:Random Allocation; D012120:Respiration Disorders; D016037:Single-Blind Method; D012894:Sleep Stages / Q000187:drug effects; D012893:Sleep Wake Disorders / Q000209:etiology / Q000628:therapy*