Access to computerised analysis of intrapartum cardiotocographs improves clinicians’ prediction of newborn umbilical artery blood pH

Abstract

Please cite this paper as: Costa A, Santos C, DAyres-, de-Campos, Costa C, Bernardes J. Access to computerised analysis of intrapartum cardiotocographs improves clinicians’ prediction of newborn umbilical artery blood pH. BJOG 2010;117:1288–1293.

Objective To evaluate the impact of access to computerised cardiotocograph (CTG) analysis on reproducibility and accuracy of clinicians’ predictions of umbilical artery blood pH (UAB pH) and 5-minute Apgar score.

Design Prospective evaluation of pre-recorded cases.

Setting A tertiary-care university hospital.

Population From databases of intrapartum CTGs acquired in singleton term pregnancies, 204 tracings with low signal loss and short time interval to delivery were consecutively selected.

Methods Tracings were randomly assigned to computer analysis by the Omniview-SisPorto 3.5^® system (study group n = 104) or to no analysis (control group n = 100). Three experienced clinicians evaluated all tracing printouts independently and were asked to predict the newborns’ UAB pH and 5-minute Apgar scores from them.

Main outcome measures Interobserver agreement (measured by the intraclass correlation coefficient [ICC]) and accuracy in prediction of neonatal outcomes with 95% CI.

Results Agreement on prediction of UAB pH was significantly higher in the study group (ICC = 0.70; 95% CI 0.61–0.77) than in the control group (ICC = 0.43; 95% CI 0.21–0.60), and a trend towards better agreement was also seen in estimation of 5-minute Apgar scores (ICC = 0.55; 95% CI 0.38–0.68 versus ICC = 0.43; 95% CI 0.25–0.57). Observers predicted UAB pH values correctly within a 0.10 margin in 70% of cases in the study group (95% CI 0.61–0.79) versus 46% in the control group (95% CI 0.35–0.56). They predicted 5-minute Apgar scores within a margin of one in 81% of cases in the study group (95% CI 0.73–0.88) and in 70% of cases in the control group (95% CI 0.61–0.79).

Conclusions Prediction of UAB pH is more reproducible and accurate when clinicians have access to computerised analysis of CTGs.