title: Relations between behavioral and cardiac autonomic reactivity to acute pain in preterm neonates.
abstract: OBJECTIVE
  The purpose of this study was to assess relations and concordance between behavioral and physiologic reactivity to pain in preterm neonates at 32 weeks postconceptional age as a function of gestational age at birth.
  
  
  METHODS
  Level III neonatal intensive care unit.
  
  
  METHODS
  The study group comprised 136 preterm neonates (mean [range] birthweight, 1,020 g [445-1,500 g]: gestational age at birth, 28 weeks [23-32 weeks]) separated into three groups according to gestational age at birth as follows: 23 to 26 weeks (n = 48), 27 to 29 weeks (n = 52), and 30 to 32 weeks (n = 36).
  
  
  METHODS
  Reactivity to routine blood collection at 32 weeks postconceptional age was assessed using bedside-recorded behavioral and autonomic measures. Coders who were blinded to the study design scored behavioral responses (facial activity using the Neonatal Facial Coding System, sleep/waking state, and finger splay). Autonomic reactivity was assessed by change in heart rate and spectral analysis of heart rate variability (change in low-frequency and high-frequency power, and the ratio of low-frequency to high-frequency power during blood collection).
  
  
  RESULTS
  Facial activity and state correlated moderately with change in heart rate across gestational age groups (r = 0.41-0.62). Facial activity and state did not correlate significantly with change in low-frequency and high-frequency power, or the ratio of low-frequency to high-frequency power (r = 0.00-0.31). Finger splay did not correlate with any autonomic recording (r = 0.03-0.41). Concordance between established biobehavioral measures of pain revealed individual differences. Although some neonates showed high behavioral but low physiologic reactivity, other neonates displayed the opposite reaction; however, the majority displayed concordant reactions.
  
  
  CONCLUSIONS
  The study findings confirm the value of measuring domains independently, especially in neonates born at a very young gestational age.
authors.affiliation: Center for Community Health and Health Evaluation Research, British Columbia Research Institute For Children's and Women's Health, Vancouver, Canada. smorison@cw.bc.ca
authors.forename: S J
authors.initials: SJ
authors.lastname: Morison
authors.forename: R E
authors.initials: RE
authors.lastname: Grunau
authors.forename: T F
authors.initials: TF
authors.lastname: Oberlander
authors.forename: M F
authors.initials: MF
authors.lastname: Whitfield
mesh_terms: D000208:Acute Disease; D001341:Autonomic Nervous System / Q000503:physiopathology*; D005260:Female; D005865:Gestational Age; D006329:Heart Conduction System / Q000503:physiopathology*; D006801:Humans; D018730:Infant Behavior; D007231:Infant, Newborn; D007234:Infant, Premature; D008297:Male; D010146:Pain / Q000503:physiopathology*