Temperature Control of Infants with/without Asphyxia during Transport

Abstract

Background: Therapeutic hypothermia (TH) has been shown to improve the outcome following perinatal asphyxia. To obtain the maximum benefit, therapeutic hypothermia should be initiated as soon as possible within 6 hr after birth. In Japan, it is important to develop effective and safe protocols to control the temperature during transport. Objective: To evaluate the efficacy and safety of continuous monitoring of rectal temperatures during transport of infants with/without asphyxia in order to control body temperature properly and to induce passive cooling for infants with mild to severe Hypoxic-ischemic-encephalopathy (HIE) safely. Methods: Skin and rectal temperatures during transport were prospectively collected from transported newborns between August 2012 and August 2014 at three regional cooling centers. In the case of infants without asphyxia, the transport team controlled the temperature of the transport incubator 33 ± 2°C to maintain a target rectal temperature at as close to 36.0-36.5°C as possible. While in the case of infants with asphyxia, the transport team controlled the temperature of the transport incubator between 31 and 32°C to maintain a target rectal temperature at as close to 35.0°C as possible. The rectal and skin temperatures were monitored continuously and recorded by the bedside monitor for later analysis. Results: In the 2 year study period, the skin and rectal temperatures of 52 newborns without asphyxia were monitored continuously. The median gestational age and birth weight of them were 38.1 (36.0-41.3) weeks and 2905 (1904-4408) g. The rectal temperature is correlated significantly with skin temperature (p 35.5°C. One of 4 mild HIE infants had a rectal temperature at arrival between 34.5-35.5°C and three >35.5°C. Only one preterm infant with severe HIE was overcooled. Conclusion: Passive cooling by controlling the transport incubator temperature for infants with HIE was relatively safe and could prevent to be elevated body temperature. However, there may be a risk of unintended excessive cooling, especially in severe HIE infants and preterm infants during longer transfer. We suggest that continuous monitoring of the rectal temperature to control body temperature during transport especially for passive cooling is mandatory. We need further studies to clarify protocols to control body temperature of infants during transport including passive cooling.