Anisuddin Ahmed: Development and testing of a reusable Thermal Jacket for managing hypothermia among preterm or low birthweight neonates in Bangladesh

Abstract

Background: Neonatal hypothermia remains a leading yet preventable contributor to morbidity and mortality among preterm and low birthweight (LBW) neonates, particularly in low- and middle-income countries where access to conventional thermal care technologies is severely constrained. While Kangaroo Mother Care (KMC) remains the cornerstone of thermal care in resource-limited settings, structural, logistical, physical, and social barriers significantly impede its consistent practice. This thesis presents the development and phased clinical evaluation of the Thermal Jacket, a reusable, electricity-independent neonatal thermoregulatory device designed to supplement KMC for managing hypothermia among preterm or LBW neonates in Bangladesh.

Methods: The thesis comprises four sequential studies conducted aligned with the WHO four-phase clinical trial model at different tiers of healthcare facilities in Bangladesh. Study I was a laboratory preclinical trial (81 mannequin events), which tested the device’s thermal performance across ambient conditions and reusability. Study II was a single-arm open-label safety trial (68 events among nine neonates) at a tertiary hospital. Study III was a stepped-wedge cluster-randomised trial (854 events among 150 neonates) across three secondary-level hospitals. Study IV was an exploratory qualitative study using in-depth interviews (n=30), focus group discussions (n=3), and key informant interviews (n=12).

Results: The Thermal Jacket maintained the target temperature range (36-38°C) for over 120 minutes in 98% of laboratory events, with no significant effect of ambient temperature or reuse up to 9 times on performance (Study I). In the safety trial, euthermia was maintained in 96% of events with no adverse clinical signs (Study II). The effectiveness trial showed that the Thermal Jacket, adjunct to KMC, significantly improved euthermia maintenance compared with KMC alone (91% vs. 77%; adjusted OR 2.65), with the largest gains observed among hypothermic neonates (Study III). Bayesian mediation analysis revealed that 37% of the intervention effect was mediated through increased thermal care duration. Study IV found that caregivers and healthcare providers navigated thermal care as a situated, morally informed practice, positioning the Thermal Jacket as an institutionally legitimate supplement that extended caregiving agency without displacing KMC.

Conclusions: Collectively, the evidence establishes that the Thermal Jacket is effective and clinically safe in managing hypothermia and contextually acceptable within Bangladesh's public health system, providing a strong empirical foundation for its integration into national neonatal care guidelines and scaled implementation.