title: Impaired parasympathetic response to feeding in ventilated preterm babies.
abstract: BACKGROUND
  Premature very low birthweight (VLBW) infants are born with an underdeveloped parasympathetic nervous system (PNS) which may limit their ability to respond adequately to feeding and may limit their capacities for extrauterine growth and development.
  
  
  OBJECTIVE
  To describe the patterns of autonomic response to feeding and identify relationships between change in heart period variability measures over time with selected infant characteristics.
  
  
  METHODS
  Individual growth curve analysis techniques were used to describe the patterns of change over time in sympathetic and parasympathetic tone as measured by low and high frequency heart period power.
  
  
  RESULTS
  Sixteen mechanically ventilated VLBW infants with a mean corrected gestational age of 30.4 weeks participated in the study. The low frequency (LF) power slope was -17.67 (p = 0.0002) and the high frequency (HF) power slope was -0.92 (0.0003). There was a significant relationship between HF slope and birth gestational age (r = -0.49, p = 0.05).
  
  
  CONCLUSIONS
  HF power, representing primarily parasympathetic activity, did not increase with enteral feeding as anticipated. LF power, an indicator of sympathetic tone, decreased during and after feeding suggesting the anticipated effect of inhibition of the sympathetic nervous system in response to the gut stimulus. Critically ill VLBW infants possess an overriding sympathetic response, but may not have adequate PNS tone development.
authors.affiliation: University of Utah, 10 South 2000 East, Salt Lake City, UT 84112, USA. Sandra.smith@nurs.utah.edu
authors.forename: S L
authors.initials: SL
authors.lastname: Smith
authors.forename: A K
authors.initials: AK
authors.lastname: Doig
authors.forename: W N
authors.initials: WN
authors.lastname: Dudley
mesh_terms: D001724:Birth Weight; D005260:Female; D005865:Gestational Age; D006339:Heart Rate; D006801:Humans; D007227:Infant Nutritional Physiological Phenomena / Q000502:physiology*; D007231:Infant, Newborn; D007234:Infant, Premature / Q000502:physiology*; D019102:Infant, Very Low Birth Weight / Q000502:physiology*; D007442:Intubation, Intratracheal; D008297:Male; D010275:Parasympathetic Nervous System / Q000503:physiopathology*; D012121:Respiration, Artificial; D013564:Sympathetic Nervous System / Q000503:physiopathology