Thermal Alterations in Premature Neonates

Abstract

Introduction: Preterm neonates suffer frequent thermal alterations that result in increased morbidity and mortality rates. Thermal support is used to provide stability until thermal maturation is reached. The first manifestation of thermal control is peripheral vasoconstriction, estimated as the difference between central and peripheral temperatures (ΔT). However, very little is known regarding the point in time at which this maturation occurs and what values of ΔT characterize stability. Aim: To study the maturation of thermal control and temperature trends over time. To assess the possibility of improving the temperature settings of the neonatal incubators to minimize hypothermia and hyperthermia. To evaluate the potential of using ΔT as an indicator of stability or marker for sepsis. Methods: Very premature neonates (< 32 weeks of gestational age) admitted to the Neonatal Intensive Care Unit of the Erasmus Medical Center were included in the study. Peripheral and central body temperatures were recorded continuously for a maximum of 10 days were included. The temperature patterns were visually analyzed for possible trends over time. The percentage of time in which the neonates had hypothermia and hyperthermia was evaluated. The relation between adjustments in the incubator set temperature and the effects in the neonatal temperatures before and after the change were analyzed. Results: Fifteen neonates were included in the pilot study. All the neonates presented stable body temperatures for at least 72.8% of the time. No maturation of thermal control could be observed over time. ΔT was observed to increase with gestational age. Extreme premature neonates kept a consistent ΔT < 2°C, with slightly altered values in cases with sepsis (20% of the neonates). Temperatures of the neonates were mostly outside the stable range before an adjustment in the set temperature was made. Conclusions: ΔT might have the potential to help distinguishing between periods of stability, episodes of sepsis or hyperthermia. Preventive actions regarding adjustments of incubator set temperature could help minimizing episodes of hypothermia and hyperthermia.