Servocontrol of skin temperature for the critically ill premature neonate nursed on a radiant warmer bed has been assumed to be analogous to skin temperature control for infants nursed in convection-warmed incubators. There are significant differences between these two warming techniques, and no definitive data exist to aid the clinical specialist in governing radiant warmer control. Eighteen low birth weight premature infants less than 2 weeks of age were studied under powerful overhead radiant warmers to determine the optimal skin temperature for servocontrol of radiant heater output. Anterior abdominal wall temperature was servocontrolled at 35.5 degrees, 36.5 degrees, and 37.5 degrees C in a randomized fashion for three periods of 90 minutes each after thermal equilibrium was established. Oxygen consumption was measured during the entire 90-min sample period at each temperature by a computerized metabolic apparatus to determine the optimal thermal neutral control temperature defined as minimal oxygen consumption with normal body temperature. Skin, deep rectal, and environmental temperature measurements, as well as behavior assessments, were made concurrently. Oxygen consumption was significantly elevated at 35.5 degrees C (8.62 +/- 0.73 mL/kg/min, mean +/- SEM) compared with 36.5 degrees C (7.30 +/- 0.55 mL/kg/min). Changing servocontrol temperature to 37.5 degrees C produced no further significant decrease in oxygen consumption (7.41 +/- 0.70 mL/kg/min), and nine infants manifested supranormal deep rectal temperatures (greater than 37.5 degrees C). Optimal abdominal skin temperature control at 36.5 degrees C (slightly warmer than previously reported but less than 37.5 degrees C) is recommended for premature neonates nursed on radiant warmer beds.(ABSTRACT TRUNCATED AT 250 WORDS)