52: Evaluation of an external fetal ECG monitoring system: a randomized controlled trial

Abstract

To compare interpretability of two intrapartum abdominal fetal heart rate (FHR) monitoring strategies. We hypothesized that an external fetal electrocardiogram (fECG) monitoring system, a new technology using cable-free abdominal pads, would produce more interpretable FHR data compared to standard of care (SOC) external Doppler FHR monitoring. Randomized trial conducted at 4 Utah hospitals. Patients were enrolled at labor admission and randomized in blocks based on body mass index (BMI) to SOC or fECG. Primary outcome was the percentage of interpretable minutes of FHR tracing. An interpretable minute was defined as >25% FHR data present and no more than 25% continuous missing FHR data or artifact present. FHR tracings were read in blinded fashion by two reviewers. We also considered the rate of successful device set up, defined as the ability to obtain any interpretable FHR tracing, as well as the number of interpretable 10 minute FHR segments, device adjustments, clinical outcomes, and patient/provider device satisfaction as determined by Likert scale survey. We calculated that 100 patients per arm (200 total) would be needed to detect a 5% difference in interpretability with 95% power. 218 women were randomized, 108 to fECG and 110 to SOC (Figure). Device set up failure occurred more often in the fECG group (7.4% vs 0% for SOC). There were no differences in the primary outcome or 10 minute FHR segment analyses, but fECG produced more interpretable FHR tracing in BMI≥30 (Table). Maternal demographics and clinical outcomes were similar between arms. More device changes occurred in the fECG group, however fECG use required fewer nursing adjustments compared to SOC. There was no difference in physician device satisfaction between groups, but fECG generated higher patient device satisfaction scores. Although the primary outcome did not differ between groups, patients preferred the fECG system. Significant differences were noted with BMI stratification, where fECG outperformed SOC in women with BMI≥30. To our knowledge, this is the first randomized clinical comparison of an external fECG device and SOC. Further investigation should focus on predictors of fECG device failure and determining settings in which fECG may be the preferred and more cost-effective FHR monitoring strategy.View Large Image Figure ViewerDownload Hi-res image Download (PPT)