When attending a preterm delivery, we all learned that the cornerstones of resuscitation are the ABCs: airway, breathing, and circulation. Simple concepts that can take years to master. After any resuscitation, we are so focused on heart rate and oxygenation that the baby’s temperature may be the last thing on our minds. It is often the very last vital sign we obtain, finally checked as we get ready to transfer to the NICU. If they are cold, we’ll just warm them up when we get to the NICU, right? No big deal?
Unfortunately, early hypothermia seems to be much more dangerous than we might think. This week, Pediatrics is early releasing an article by Marije Hogeveen, MD, PhD, Lotty Hooft, PhD, and Wes Onland, MD, PhD, from Amalia Children’s Hospital, Utrecht University, and Amsterdam University Medical Center in the Netherlands, entitled “Hypothermia and Adverse Outcomes in Very Preterm Infants: A Systematic Review” (10.1542/peds.2024-069668). In this study, the authors sought to determine the impact of admission hypothermia on outcomes for very preterm infants (<32 weeks or <1500g).
They performed a systemic review that evaluated 32 studies including over 300,000 subjects from mostly high- and middle-income countries born in hospital settings. They identified 23 of these studies that reported mortality data for their meta-analysis and performed subgroup and sensitivity analyses demonstrating the robustness of their results.
So what did they find?
- Infants with admission hypothermia had double the odds of death compared to normothermic infants, with a corrected odds ratio (cOR) of 2.02 [95% confidence interval (CI) 1.84–2.21], p<0.00001.
- When using a temperature cutoff of less than 36 degrees Celsius, they found the cOR for death was 2.44 [95% CI 2.12–2.8] compared to normothermic infants.
- But even evaluating less severe hypothermia (less than 36.5 degrees Celsius), the odds of death was still double compared to normothermia, with cOR 1.98 [95% CI 1.8–2.19].
- Admission hypothermia was also significantly associated with increased odds of developing chronic lung disease of prematurity, intraventricular hemorrhage, retinopathy of prematurity, and sepsis.
- There were no differences between middle- and high-income countries.
These results demonstrate that premature infants experiencing early hypothermia are at increased risk of serious comorbidities and death. Although the authors found heterogeneity in their data, their sensitivity analysis demonstrated consistent results.
Moving forward, admission hypothermia must be recognized as a predictor of neonatal mortality and morbidity in the preterm population. We must focus more vigorously on appropriate thermoregulation before, during, and after neonatal resuscitation as well as upon admission to the NICU.
Think about it . . . interventions in the delivery room to simply maintain normothermia could cut the odds of death in half for our patients. It’s time we reframe the ABCs to move “temperature” to the forefront of our minds as well. Maybe it’s time for the ABCTs?
