A Research Program to Examine Evidenced-Based Practices in Newborn Thermoregulation

Background: Thermoregulation is a critical component of neonatal care. Practices surrounding thermoregulation have not been re-tested though the frontier of viability has markedly changed. Maintaining a neutral thermal environment (NTE) is one foundation of care for this population. There is no easy way to determine whether an infant is in his or her NTE. Rather clinicians have extrapolated data from historical studies that have determined the correlation between O2 consumption, rectal temperature, and skin temperature. These studies were conducted on infants that did not reflect the demographics of the infant population in modern NICUs. Less than 20 years ago, the survival for infant <1000 grams was a rare event. Hence, some of these data need to be re-examined to determine if practices surrounding temperature control are still valid and to determine if the methods of driving heater control algorithms are influenced by these demographic differences. Further, one should realize that approximately 50% of the nurseries in the world practice a baby-control philosophy to thermoregulation while others practice an air-control philosophy. Does the data show that one approach is better for the baby that the other?

Objective: A thermoregulatory research group has been convened at Universitätsklinikum Mannheim. During the first phase, the primary goal is to evaluate and compare thermal and physiological homeostasis of very low birthweight infants during two methods of heating control (baby versus air control conditions) during the first week of life. Specific primary outcome measures will be the effect of heating method on skin and core temperatures, heart and respiratory rates, blood pressure, SpO2, pH, PaO2, and PaCO2.

Methods: 30 infants <1500 grams will be randomized to the following conditions: Giraffe baby mode versus Giraffe air mode. The Giraffe bed will be set-up and pre-warmed according to manufacturer's guidelines in closed bed/incubator/manual mode, using temperature recommendations from the Comfort ZoneTM chart. Admission temperatures will be documented and procedures will be conducted in their usual manner. The baby will then be randomized to baby versus air mode. The initial thermal goal will be to maintain skin temperature at 36.5 degrees C in both groups and rectal temperature within a range of 36.5 to 37.2 degrees C. Humidity will be controlled for the period of data collection. Variations in the level of humidity will be statistically handled as a covariate. Rectal temperature will be monitored at least every 4 hours.

Results: Data on 15 of 30 babies has been collected. To date, 93% of babies in baby control spend more time in the defined “normal“ range versus 84% in air mode, p=0.005. Further analysis is pending data collection. It is anticipated the findings derived from this investigation will strengthen the evidenced-based approach to clinicians.

Variable	Baby Mode	Air Mode	P Value
% time skin temp 36.5–37.2° C	93	84	.005
Average skin temperature (@ thermistor)	36.7	36.3	.02
Average rectal temperature	36.8	36.6	.06
Average set relative humidity	65%	68%	.09