Revista de Técnicas Diagnósticas e Análise Biomédica

A Computerized Automatic Diagnosis of Fetal Heart Rate

Kazuo Maeda

Background: The author started automated fetal heart rate diagnosis in1970s by using HP 2100A. Minicomputer with the purpose to automatically diagnose Hon’s deceleration patterns. Fetal heart rate meter was an autocorrelation fetal heart rate meter with fetal heart sound, where it was unable to connect the heart rate meter directly to computer because the computer core memory was only 4 k-bytes. The heart rate and uterine contraction was punched to 8 bits paper tape. The data interval was 2 seconds in 5 minutes, namely each 150 data were punched in 5 minutes, which was traditional in our fetal heart rate analysis till present. The paper tape was read by a tape reader and the data were stored in core memory and analyzed by the system programmed using HP BASIC interpreter by the author. Heart rate baseline: The heart rate data was counted in 10 bpm steps to detect the step of the most heart rate data, where the averaged heart rate in the most step was the baseline heart rate in 5 minutes. Variability: The amplitude of baseline variability was averaged to achieve baseline variability amplitude.