Fetal heart rate and amniotic fluid volume measurements with a home ultrasound device.

Objective: Pulsenmore ES is a self-scanning ultrasound system for remote fetal assessment. It is composed of a hand-held transducer that serves as a smartphone cradle coupled with an application and clinician's web-viewer dashboard. Recently, a novel capability was added to the system allowing for offline fetal heart rate (FHR) and maximal vertical pocket (MVP) measurements. The aim of this study was to evaluate these tools for usability and accuracy.

Study design: A prospective, non-randomized, non-blinded clinical study design was used. Pulsenmore ES scans were obtained by non-professional laypersons in app-guided (AG) mode (user follows video tutorials in the application) or clinician-guided (CG) mode (user is guided by a health-care professional in a real-time telemedicine visit). The scans were stored on a cloud for later interpretation by a health-care professional. Each self-scan was immediately followed by a standard ultrasound scan performed by a clinician. The asynchronous FHR and MVP measurements made on the AG and CG scans through the designated dashboard were analyzed and compared with the real-time, in-clinic, measurements.

Results: The cohort included 28 women. Rates of successful utilization of the Pulsenmore tool for measurement of FHR were 84.7±11.24% of scans made in AG mode and 96.3±6.35% of scans made in CG mode. Corresponding values for MVP were 91.7±2.31% and 95.0±1.73%. FHR accuracy (difference from in-clinic values) was 10.8±7.5 bpm (7.2%) in AG mode and 5.8±5.1 bpm (4%) in CG mode; MVP accuracy was 1.3±1.4cm (22%) and 0.9±0.8cm (14%), respectively. Sensitivity (87.5% and 100%, in AG and CG modes respectively) and specificity (95% and 95.5%, in AG and CG modes, respectively) were established for MVP.

Conclusion: FHR and MVP measurements obtained from scans captured by the self-operated Pulsenmore ES ultrasound platform are highly accurate and reliable for clinical use relative to standard in-clinic measurements.