Web-based comparison of historical vs contemporary methods of fetal heart rate interpretation

Abstract

Background: Contemporary interpretation of fetal heart rate patterns is based largely on the tenets of Drs Quilligan and Hon. This method differs from an older method that was championed by Dr Caldeyro-Barcia in recording speed and classification of decelerations. The latter uses a paper speed of 1 cm/min and classifies decelerations referent to uterine contractions as type I or II dips, compared with conventional classification as early, late, or variable with paper speed of 3 cm/min. We hypothesized that 3 cm/min speed may lead to over-analysis of fetal heart rate and that 1 cm/min may provide adequate information without compromising accuracy or efficiency.

Objective: The purpose of this study was to compare the Hon-Quilligan method of fetal heart rate interpretation with the Caldeyro-Barcia method among groups of obstetrics care providers with the use of an online interactive testing tool.

Study design: We deidentified 40 fetal heart rate tracings from the terminal 30 minutes before delivery. A website was created to view these tracings with the use of the standard Hon-Quilligan method and adjusted the same tracings to the 1 cm/min monitoring speed for the Caldeyro-Barcia method. We invited 2-4 caregivers to participate: maternal-fetal medicine experts, practicing maternal-fetal medicine specialists, maternal-fetal medicine fellows, obstetrics nurses, and certified nurse midwives. After completing an introductory tutorial and quiz, they were asked to interpret the fetal heart rate tracings (the order was scrambled) to manage and predict maternal and neonatal outcomes using both methods. Their results were compared with those of our expert, Edward Quilligan, and were compared among groups. Analysis was performed with the use of 3 measures: percent classification, Kappa, and adjusted Gwet-Kappa (P < .05 was considered significant).

Results: Overall, our results show from moderate to almost perfect agreement with the expert and both between and within examiners (Gwet-Kappa 0.4-0.8). The agreement at each stratum of practitioner was generally highest for ascertainment of baseline and for management; the least agreement was for assessment of variability.

Conclusion: We examined the agreement of fetal heart rate interpretation with a defined set of rules among a number of different obstetrics practitioners using 3 different statistical methods and found moderate-to-substantial agreement among the clinicians for matching the interpretation of the expert. This implies that the simpler Caldeyro-Barcia method may perform as well as the newer classification system.

Keywords: Caledyro-Barcia; Hon-Quilligan; fetal heart monitoring.