Altered autonomic function and reduced arousability in apparent life-threatening event infants with obstructive sleep apnea

Am J Respir Crit Care Med. 2002 Apr 15;165(8):1048-54. doi: 10.1164/ajrccm.165.8.2102059.


The aim of this study was to examine cardiorespiratory control in infants presenting with an apparent life-threatening event (ALTE). We performed six to eight 45 degrees head-up tilts in 10 ALTE infants (age, 14 +/- 3 weeks) and 12 age-matched control subjects during slow wave sleep and rapid eye movement sleep (REM). All infants underwent full overnight polygraphic sleep recordings with noninvasive measurement of beat-to-beat blood pressure. All control infants had normal sleep breathing. In contrast, 5 of the 10 ALTE infants had more than two obstructive apneas per hour of sleep, with short hypoxic episodes (obstructive sleep apnea [OSA]). In slow wave sleep, in response to the tilt, the ALTE infants with OSA showed a reduced heart rate response, and three of the five showed a marked postural hypotension. The ALTE infants with OSA also had altered heart rate and blood pressure variability and an increased arousal threshold in REM (p = 0.0002). By contrast, those ALTE infants with normal sleep breathing had cardiovascular and arousal responses similar to those of the control infants. We conclude that a number of ALTE infants with OSA have abnormal cardiovascular autonomic control that, combined with their decreased arousability in REM, may provide an explanation for the ALTE episodes.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Arousal / physiology*
  • Autonomic Nervous System / physiopathology*
  • Blood Pressure
  • Cardiovascular System / innervation
  • Heart Rate
  • Humans
  • Infant
  • Polysomnography
  • Risk Factors
  • Sleep Apnea, Obstructive / physiopathology*
  • Sudden Infant Death*