Prevention of NICU Admission Hypothermia in Moderate- and Late-Preterm Infants.

Background: Neonatal hypothermia is a common and preventable cause of neonatal morbidity and mortality. Although hypothermia prevention has been extensively studied in infants <32 weeks' gestation, the authors of few studies have targeted moderate- and late-preterm infants (MLPIs) in the delivery room.

Methods: This quality improvement initiative was conducted from June 2019 to June 2023 at the Massachusetts General Hospital NICU and Labor and Delivery Unit. All inborn MLPIs 32 + 0/7 to 36 + 6/7 weeks' gestation admitted to the NICU were included. We expanded thermoregulatory measures typically used in protocols for infants <32 weeks' gestation, including increasing delivery room ambient temperature to 74°F and thermal mattress use. The primary outcome was hypothermia (<36.5°C) after NICU admission. The balancing measure was hyperthermia (≥38 °C).

Results: During the study period, there were 566 inborn MLPIs with a mean gestational age of 34 + 3/7 weeks and a mean birth weight of 2269 g. Special cause variation in neonatal hypothermia incidence was observed with a decrease from a mean baseline of 27% to 7.8% postintervention. Special cause variation was observed in hyperthermia incidence, with an increase from 1.4% to 6.2% postintervention largely initially associated with noncompliance with the protocol for thermal mattress removal.

Conclusions: The expansion of several thermoregulation techniques commonly used in infants <32 weeks' gestation, particularly thermal mattress use, was associated with a decreased incidence of NICU admission hypothermia in MLPIs, with an increase in mild hyperthermia predominantly associated with concomitant polyethylene wrap use.