Physiologic and Pharmacologic Effects of Therapeutic Hypothermia for Neonatal Hypoxic Ischemic Encephalopathy

Cooling strategies during neonatal transport for hypoxic-ischaemic encephalopathy

AIM

We reviewed the literature on cooling methods during transport of newborn infants with hypoxic-ischaemic encephalopathy (HIE) born in a non-tertiary centre and transferred to a neonatal intensive care unit for therapeutic hypothermia.

METHODS

The electronic databases CENTRAL, MEDLINE, Embase, CINAHL, and Scopus were searched from inception up to 8 March 2022 for studies comparing cooling versus no cooling, active versus passive cooling, and servo-controlled versus non-servo-controlled cooling. Odds ratio and confidence of interval were calculated for dichotomous outcomes and mean difference and confidence interval for continuous outcomes.

RESULTS

The final analysis included 14 studies, 1 randomised and 13 non-randomised, involving 1098 newborn infants. Compared with the other cooling methods, servo-controlled active cooling was more likely to maintain body temperature within the target range of 33°C-34°C on arrival at a neonatal intensive care unit: odds ratio 13.58, 95% confidence interval 4.32-42.66, risk difference 0.33, 95% confidence interval 0.19-0.46; 224 participants; three studies; I² 0%. The certainty of evidence was low. Only five studies reported mortality rates.

CONCLUSION

Servo-controlled active cooling may be the preferred method during transport of newborn infants with HIE. A future area of focus should be long-term neurodevelopmental outcomes after servo-controlled active cooling.

"Caution! Contents should be cold": developing a whole-body hypothermia program

Hypoxic-ischemic encephalopathy (HIE) is characterized as brain injury that results from lack of oxygen or blood flow to the brain in the perinatal period. Neonatal whole-body hypothermia and selective head cooling are becoming increasingly common care practices across the U.S. and Canada for infants with moderate-to-severe HIE because of the demonstrated ability of these approaches to reduce reperfusion injury to the brain. Health care professionals must develop a clinical care path for these fragile infants. For best results, induced hypothermia should be initiated within six hours of birth; therefore, care must be organized and provided without delay. This article provides bedside clinicians with care recommendations for infants being treated with these new interventions.