Time-sensitive predictors of thermoregulation in preterm infants: A decision tree analysis during the early postnatal...

Maintaining normothermia is essential for the survival of preterm infants; however, the hour-to-hour determinants of thermoregulation in infants receiving respiratory support remain poorly understood. This study aimed to identify time-sensitive predictors of axillary temperature during the first 6 h after birth.

This retrospective observational study used hour-specific classification and regression tree (CART) analyses to explore time-sensitive predictors of axillary temperature in 300 preterm infants admitted immediately after birth who required respiratory support. Hourly temperatures and relevant perinatal, respiratory, and environmental variables were extracted from clinical records. For each hour, temporally segmented CART models were generated using only variables available up to that time point. To reduce overfitting, tree depth was restricted to four levels. Model performance was assessed using R², mean absolute error, and root mean square error. Differences in hourly temperatures were evaluated using the Friedman test.

Axillary temperature increased gradually over the first 6 h after birth. Birth-related anthropometric measures were the predominant determinants during the earliest hours, whereas respiratory and oxygenation parameters emerged as the strongest contributors as the postnatal period progressed. Hour-specific CART analyses demonstrated a temporal shift in predictor importance, suggesting rapid physiological transition during the early postnatal period.

The determinants of early temperature regulation in preterm infants shift from birth-related physiology characteristics to respiratory factors during the first hours after birth. These findings improve our understanding of the temporal evolution of thermoregulation during the early postnatal period and provide a foundation for future research on time-sensitive thermal management strategies.