[Automated fetal heart rate analysis and its trendgram in relation to gas analysis and acid-base balance of umbilical cord arterial blood].

The gas analysis and acid-base balance of the umbilical cord arterial blood of 108 newborn infants were compared with the results of the automated analysis of the intrapartum fetal heart rate (FHR) and its trendgrams. The parameters of the automated analysis of the FHR, which consisted of fetal distress (FD) index, uterine contraction area, FHR score, number of dips, baseline heart rate, variability amplitude and lag time, were shown on the trendgram every 5 minutes using a microcomputer. 1) The mean pH, BE and HCO3- of the 4 groups, that showed 0, 1, 2 and 3 or more on the FD index, were gradually decreased as the FD index was increased. 2) The FHR score, that was accumulated for 10 minutes from 0-10 minutes to 50-60 minutes prior to the birth, was well correlated with the umbilical cord arterial blood pH (r = -0.47), BE (r = -0.60) and HCO3- (r = -0.45). 3) The intrapartum trendgrams were classified into the normal and ominous groups on the basis of the FHR score and FD index. The differences between the respective mean pH, BE, HCO3-, PO2 and PCO2 for these groups were highly significant. 4) The specificity and the sensitivity of the trendgram were more than 70% in the prediction of a pH value lower than 7.25 and of a BE value lower than -6.0 mEq/l.