Assessment of rewarming methods in unplanned out-of-hospital births from a prospective cohort.

Background: Mobile intensive care units frequently manage unplanned out-of-hospital births (UOHB). Rewarming methods during pre-hospital management of UOHB have not yet been compared. The aim was to compare rewarming methods used during pre-hospital management in a large prospective cohort of UOHB in France.

Methods: We analysed UOHB from the prospective AIE cohort from 25 prehospital emergency medical services in France. The primary outcome was the change in body temperature from arrival at scene to arrival at hospital.

Results: From 2011 to 2018, 1854 UOHB were recorded, of whom 520 were analysed. We found that using incubator care was the most effective rewarming method (+ 0.8 °C during transport), followed by the combination of plastic bag, skin-to-skin and cap (+ 0.2 °C). The associations plastic bag + cap and skin-to-skin + cap did not allow the newborn to be warmed up but rather to maintain initial temperature (+ 0.0 °C). The results of the multivariate model were consistent with these observations, with better rewarming with the use of an incubator. We also identified circumstances of increased risk of hypothermia according to classification and regression tree, like premature birth (< 37 weeks of gestation) and/or low outside temperature (< 8.4 °C).

Conclusions: Using an incubator was the most effective rewarming method during pre-hospital management of UOHB in our French prospective cohort. Based on our model, in cases of term less than 37 weeks of gestation or between 37 and 40 weeks with a low outside temperature or initial hypothermia, using such a method would be preferred.