A comparison of visual and automated methods of analyzing fetal heart rate tests

Abstract

Objectives: Our objective in this study was to compare evaluation and clinical implications of visual versus computerized analysis of nonstress tests.

Methods: Nonstress tests of 575 high-risk patients were analyzed visually and by a computer using the Oxford Sonicaid System 8000. Standard reactivity criteria were used for visual assessment; the System 8000 used an algorithm with the Dawes-Redman criteria.

Results: Ninety-six percent of nonstress tests that met Dawes-Redman criteria were reactive by visual analysis; 93% of reactive nonstress tests met Dawes-Redman criteria. Only 30% of tests that failed Dawes-Redman criteria were nonreactive, whereas 44% of nonreactive tests failed to meet Dawes-Redman criteria. Sensitivities, specificities, and positive and negative predictive values were similar for both approaches. Additional tests or interventions would have occurred in 9% of the cases analyzed by System 8000 and in 49% of the cases analyzed visually.

Conclusions: Although these approaches rate nonstress tests differently, their diagnostic performances are similar. Automated fetal heart rate testing may become an acceptable alternative to conventional visual analysis.