Does admission hypothermia predispose to intraventricular hemorrhage in very-low-birth-weight infants?

Background: The etiology of intraventricular hemorrhage (IVH) in very-low-birth-weight (VLBW) infants is multifactorial and is associated with low gestational age (GA) and severity of neonatal respiratory disease. The role of admission hypothermia (AHT) in the pathogenesis of IVH in VLBW infants has not yet been elucidated. We searched risk factors for IVH in VLBW infants while focusing on AHT. Patients and Methods: VLBW infants ≤33 weeks' gestation from three participating medical centers were included. From patients' medical charts we collected variables known to be associated with IVH, focusing on AHT. AHT was defined as rectal temperature ≤35.5°C at admission to the NICU. Head ultrasound was performed at 2-5 and 6-10 days of age and before discharge. Results: 271 VLBW infants were studied. Univariate analysis showed that AHT at ≤35.5°C was not significantly associated with IVH (all grades; p = 0.16), but associated with IVH grade 3-4 (p = 0.034), while AHT at ≤35°C was significantly associated with IVH (p = 0.036) and with IVH grade 3-4 (p = 0.003). Multivariate logistic regression analysis showed that AHT (at ≤35.5 and at ≤35°C) were not associated with IVH. Only four variables were independently significantly associated with IVH: GA, use of nitric oxide, hypocarbia and base deficit >10. Four variables were strongly associated with severe IVH (grades 3-4): GA, hypotension, base deficit >10 and hyponatremia. Conclusions: In VLBW infants, AHT at ≤35.5 and at ≤35.0°C were not significantly associated with IVH. GA, use of nitric oxide, hypocarbia and base deficit >10 were strongly associated with IVH.