title: The efficacy of individual computer heart rate indices in detecting acidemia at birth in growth-restricted fetuses.
abstract: OBJECTIVE
  To determine the efficacy of individual fetal heart rate (FHR) indices, as determined by computer analysis of the FHR tracing, in detecting fetal acidemia at birth in growth-restricted fetuses.
  
  
  METHODS
  The study population consisted of 38 growth-restricted fetuses at 26-37 weeks' gestation from pregnancies with abnormal uterine and/or umbilical artery Doppler velocimetry. The 1-hour FHR tracing was analyzed by computer within 4 hours of cesarean birth before the onset of labor. Umbilical artery cord blood was collected at birth, and pH was determined within 5 minutes of collection.
  
  
  RESULTS
  On linear regression, the duration of episodes of low variation in minutes (r = -0.77, r2 = 0.59) and short-term (r = 0.72, r2 = 0.52) and long-term (r = 0.69, r2 = 0.47) variation in milliseconds were significantly related to umbilical artery pH at birth, and more so than the number of accelerations of ten (r = 0.57, r2 = 0.32) and 15 (r = 0.38, r2 = 0.14) beats per minute. There were significant differences in computer measurements of FHR accelerations and variation between the umbilical artery pH categories of acidemia (pH less than 7.20), preacidemia (7.20-7.25), and nonacidemia (greater than 7.25). Stepwise regression revealed that episodes of low variation best described the model for predicting umbilical artery pH at birth (P < .001), with no improvement provided by the addition of other computer-analyzed FHR characteristics.
  
  
  CONCLUSIONS
  In this population of growth-restricted fetuses delivered by elective cesarean, the computer indices of duration of episodes of low variation and short-term and long-term variation were significantly associated with umbilical artery pH and predicted umbilical artery acidemia at birth.
authors.affiliation: Department of Obstetrics, University of Medicine and Dentistry of New Jersey-Robert Wood Johnson Medical School, New Brunswick, USA.
authors.forename: E R
authors.initials: ER
authors.lastname: Guzman
authors.forename: A M
authors.initials: AM
authors.lastname: Vintzileos
authors.forename: M
authors.initials: M
authors.lastname: Martins
authors.forename: C
authors.initials: C
authors.lastname: Benito
authors.forename: C
authors.initials: C
authors.lastname: Houlihan
authors.forename: M
authors.initials: M
authors.lastname: Hanley
mesh_terms: D000138:Acidosis / Q000097:blood / Q000151:congenital / Q000175:diagnosis*; D000328:Adult; D002585:Cesarean Section; D005260:Female; D005312:Fetal Blood / Q000737:chemistry; D005315:Fetal Diseases / Q000175:diagnosis*; D005317:Fetal Growth Retardation / Q000150:complications*; D006340:Heart Rate, Fetal; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007231:Infant, Newborn; D011247:Pregnancy; D012372:ROC Curve; D012680:Sensitivity and Specificity; D012815:Signal Processing, Computer-Assisted