A comparison between computerised (mean range) and clinical visual cardiotocographic assessment.

Objective: To compare computer cardiotocographic (CTG) analysis with clinical visual analysis.
Design: A retrospective blind comparison of the two techniques of CTG assessment.
Setting: Fetal Assessment Unit, King's College Hospital, London.
Subjects: One hundred CTG traces of women referred to the unit were studied; the traces were taken after 32 weeks' gestation, within 10 days of delivery and where outcome was known.
Interventions: The CTG traces were assessed both by the computer (System 8000 computerised CTG analyser, Oxford Sonicaid Ltd) and visually, by one of us.
Main Outcome: Computer mean range from 0 to 80 in ms clinical visual CTG score from 0 to 80 (arbitrary units). A score < 20 is ominous; suspicious when between 20 and 30; and normal when > 30.
Results: There was close correlation between the computer mean range and clinical visual assessment (r = 0.78, n = 100, P = 0.001). However, there were 13 occasions where the computer classified the trace as abnormal when clinical visual assessment was normal, indicating computer false positives. All these pregnancies had normal outcomes. There were no traces where computer analysis was normal and clinical visual assessment abnormal.
Conclusions: Computerised CTG analysis gives an objective assessment which agrees closely with experienced visual assessment. It also provides a number which can be used to assess the value of fetal heart rate analysis.