title: Effect of cardiac compressions and hypothermia treatment on cardiac troponin I in newborns with perinatal asphyxia.
abstract: BACKGROUND
  The American Heart Association, the European Resuscitation and the International Liaison Committee issued new neonatal resuscitation guidelines (2010) where therapeutic hypothermia is introduced after hypoxic-ischaemic encephalopathy (HIE) in term infants to prevent brain injury. Our study aimed to investigate whether hypothermia can reduce the release of a cardiac cellular marker, cardiac troponin I (cTnI), in HIE infants compared to normothermia care, if cTnI can be used as a prognostic marker for long term neuro-developmental outcome and if cardiac compression at birth affects the level of cTnI.
  
  
  METHODS
  We retrospectively collected resuscitation data at birth and cTnI levels for the first 3 days in HIE infants who fulfilled cooling entry criteria. These infants received either normothermia care or induced hypothermia treatment in the neonatal period and were then followed up and tested by standard cognitive and motor assessments. The outcome is defined as death, disability or good.
  
  
  RESULTS
  We confirmed an increase in cTnI after cardiac compressions (p=0.003, Mann-Whitney test). We found that hypothermia significantly reduced the release of cTnI (peak level and area under the curve within 24h of age), p=0.002, linear regression. Receiver operating characteristic curves showed a level of cTnI at 24 h of age <0.22 ng/ml for normothermic and <0.15 ng/ml for hypothermic infants predicts a good outcome.
  
  
  CONCLUSIONS
  Our results suggest that hypothermia is cardio protective after HIE. The level of cTnI at 24h of age is a good prognostic marker for neuro-developmental outcome at 18-22 months in both normothermia and hypothermia infants.
authors.affiliation: Neonatal Neuroscience, School of Clinical Sciences, University of Bristol, Level D, Neonatal Neuroscience, St. Michael's Hospital, Bristol BS2 8EG, UK. Electronic address: xun.liu@bristol.ac.uk.
authors.forename: Xun
authors.initials: X
authors.lastname: Liu
authors.forename: Ela
authors.initials: E
authors.lastname: Chakkarapani
authors.forename: Janet
authors.initials: J
authors.lastname: Stone
authors.forename: Marianne
authors.initials: M
authors.lastname: Thoresen
mesh_terms: D001238:Asphyxia Neonatorum / Q000097:blood* / Q000628:therapy*; D015415:Biomarkers / Q000097:blood; D005260:Female; D006336:Heart Massage; D006801:Humans; D007036:Hypothermia, Induced; D020925:Hypoxia-Ischemia, Brain / Q000517:prevention & control*; D007231:Infant, Newborn; D008297:Male; D012189:Retrospective Studies; D016896:Treatment Outcome; D019210:Troponin I / Q000097:blood*
chemical_list: D015415:Biomarkers; D019210:Troponin I
keywords: Cardiac protection; Hypothermia; Neonates; Perinatal asphyxia; cTnI