Feasibility and usability of an obstetric ultrasound video colour overlay to assist placenta localisation to risk stratify high-risk pregnancies in rural and low- and middle-income country settings

Abstract Background In this study, we use quantitative and qualitative assessments to evaluate the feasibility and usability of an obstetric ultrasound video colour overlay to assist placenta localisation and hence risk stratify high-risk pregnancies that have a low-lying placenta. The colour overlay (designed in a previous study) simplifies clinical interpretation of ultrasound video to support screening for pregnant women in rural and low- and middle-income country (LMIC) settings who do not receive care, partly because of a trained operator shortage. Methods For feasibility, we assessed risk stratification (or checking for a low-lying placenta) of a trained sonographer (6.5 years of experience) using the combined video and colour overlay compared with a hospital freehand scan without a colour overlay. For usability, we recruited 31 Indian healthcare system clinicians in both north and south India hospital sites. We assessed clinical opinions and perceptions of the colour overlay over four study rounds of written questionnaires and a single round of oral interviews. In each round, participants interacted with 20 colour overlays on a portable tablet computer. Results For feasibility, the sonographer successfully risk stratified the 2 low-lying, high-risk placentas out of a cohort of 55 unique pregnancies (1 video per pregnancy). However, this approach also resulted in 18 false positives (normal placentas that were incorrectly labelled as low-lying). Future feasibility assessment would need to use a larger cohort of pregnancies to strengthen the preliminary findings reported here. For usability, participants gave positive written responses and reported an increase in both confidence when using the colour overlay, and trust in the colour overlay post-study compared to pre-study. From qualitative coding of interview transcripts (1,643 codes and 13 themes generated), the colour overlay was overwhelmingly perceived as an effective risk stratification tool and usable by healthcare workers in rural and LMIC settings. Non-trivial perceived challenges to translation included compliance of the colour overlay with India’s current fetal sex determination law (Pre-Conception and Pre-Natal Diagnostic Techniques Act, 1994), including compliance of targeted users of rural healthcare workers (who cannot currently legally use ultrasound devices), and ultrasound device purchase and maintenance costs. Conclusions Overall, the colour overlay was perceived favourably by clinicians. For successful adoption of the technology in the Indian healthcare system, the non-technical issues raised would need to be carefully and sensitively addressed.