Effect of bundling and high environmental temperature on neonatal body temperature

Objective. The effect of bundling and ambient heat on newborn body temperature has not been systematically studied. It was hypothesized that bundling and warm environments can elevate the newborn's temperatures to the range that would prompt clinical concern of neonatal sepsis. Methods. Twenty well, term newborns more than 1 day old were assigned to the control group (one blanket; 24.0°C room) or the experimental group (five blankets and hat; 26.6°C room). Continuous rectal probe temperatures were monitored over a 2 1/2 -hour period. Results. There were 8 control and 12 experimental newborns. The mean change in rectal temperature after 2 1/2 hours was -0.04°C (SD ± 0.23) in control newborns and + 0.56°C (SD ± 0.12) in the treatment group (P < .0001, t test). Temperatures in the treatment group rose, after an initial half-hour lag, at a linear rate of 0.27°C per hour without a plateau. Two newborns reached 38.0°C, a rectal temperature that may raise concern of infection. Conclusions. Bundling and warm environments can elevate newborn body temperature to the 'febrile' range in this age group. Physicians treating neonates with elevated temperature should ask about bundling and environmental conditions to differentiate endogenous from exogenous 'fevers.'