Meta-analysis comparing temperature on arrival at the referral hospital of newborns with hypoxic ischemic encephalopathy cooled with a servo-controlled device versus no device during transport


BACKGROUND: Therapeutic hypothermia reduces mortality and neurological injury for neonates with hypoxic ischemic encephalopathy (HIE). The aim of this meta-analysis is to evaluate use of servo-controlled devices during transport to the referral hospital.

METHODS: PubMed and Medline (Ovid) searches were used to identify studies comparing HIE patients’ temperatures on arrival at the referral hospital for those cooled with servo-controlled devices versus no device during. Random effects models were used to conduct a meta-analysis comparing the two groups’ proportion of patients arriving in the target temperature range as well as the mean and variability in body temperature on arrival. Studies’ level of evidence and risk of bias were also assessed.

RESULTS: Eight published studies with total of 573 patients met the inclusion criteria, with a “B” grade of recommendation overall. A significantly higher proportion of infants cooled with a servo-controlled device arrived in the target temperature range (pooled relative risk = 2.47, 95% confidence interval: 1.46–4.17, p < 0.001). The arrival temperature in the device cooled group was on average 0.82°C lower (95% CI: 0.29–1.35°C, p = 0.002) with an 82% lower temperature variance.

CONCLUSIONS: Although the predominance of observational studies and presence of some risks of bias somewhat limits the strength of recommendation, the existing research consistently indicates that using a servo-controlled device during transport of neonates with HIE increases the probability of arriving at the referral hospital in the target temperature range, with a lower body temperature and less variability. Future research is needed to investigate differences in mortality and neurological impairment.

*Corresponding Author: 

Joseph L. Hagan, ScD, MSPH, Assistant Professor, Baylor College of Medicine, Department of Pediatrics, Section of Neonatology, Address: Texas Children’s Hospital - Pavilion for Women, Room PFW F0720.54, 6651 Main Street, Houston, TX 77030 USA. Tel.: +1 832 824 3090; Fax: +1 832 825 7899; E-mail: