title: Does the International Classification of Disease (ICD-9) code accurately identify neonates who clinically have hypoxic-ischemic encephalopathy?
abstract: OBJECTIVE
  Hypoxic-ischemic encephalopathy (HIE) refers to neonatal neurological signs and symptoms of hypoxia and/or ischemia. Our aim was to determine the accuracy of ICD-9 codes to identify newborns with HIE confirmed by umbilical cord blood analysis.
  
  
  METHODS
  ICD-9 codes in the newborn chart for birth trauma, birth asphyxia, intrauterine hypoxia, and fetal distress were used to identify newborns with suspected HIE by neonatal personnel. Maternal charts were reviewed for umbilical cord gases meeting the HIE clinical criteria.
  
  
  RESULTS
  There were 21,008 deliveries at center I and 17,540 at center II. ICD-9 codes identified 172 neonates, 49 infants (2.3‰ births) at center I and 123 neonates (7‰) at center II. Only 3 neonates (6%) were ≥34 weeks and none met ACOG criteria [umbilical artery pH <7.00 or base excess (BE) ≥12 mmol/l at center I]. At center II, 80 infants were ≥34 weeks but only 5/123 (4%) met the ACOG clinical criteria for HIE (pH <7.00, BE ≥12 mmol/l, and Apgar ≤3 at 5 min).
  
  
  CONCLUSIONS
  ICD-9 codes are unreliable in identifying birth asphyxia and cannot identify newborns meeting the clinical criteria for intrapartum HIE.
authors.affiliation: Department of Obstetrics and Gynecology, University of Mississippi Medical Center, Jackson, Miss., USA.
authors.forename: Gregory A
authors.initials: GA
authors.lastname: Vance
authors.forename: Amy
authors.initials: A
authors.lastname: Niederhauser
authors.forename: Suneet P
authors.initials: SP
authors.lastname: Chauhan
authors.forename: Everett F
authors.initials: EF
authors.lastname: Magann
authors.forename: Joshua D
authors.initials: JD
authors.lastname: Dahlke
authors.forename: Jonathan K
authors.initials: JK
authors.lastname: Muraskas
authors.forename: John C
authors.initials: JC
authors.lastname: Morrison
mesh_terms: D000293:Adolescent; D000328:Adult; D001034:Apgar Score; D001238:Asphyxia Neonatorum / Q000145:classification; D005260:Female; D005312:Fetal Blood / Q000737:chemistry; D005316:Fetal Distress / Q000145:classification; D006801:Humans; D020925:Hypoxia-Ischemia, Brain / Q000145:classification* / Q000175:diagnosis; D007231:Infant, Newborn; D038801:International Classification of Diseases / Q000145:classification*; D011247:Pregnancy; D011248:Pregnancy Complications / Q000145:classification; D012720:Severity of Illness Index; D055815:Young Adult