The Association between Admission Hypothermia and Neonatal Outcomes in Very Low Birth Weight Infants

ABSTRACT

PURPOSE: We aimed to evaluate the effect of admission hypothermia on neonatal outcomes in very low birth weight infants (VLBWIs). METHODS: Medical records of 153 preterm infants, with birth weights <1,500 g and gestational ages <32 weeks, were retrospectively reviewed. The clinical characteristics and neonatal outcomes in infants who experienced moderate hypothermia during the first hour of life (Group I) were compared to those in infants with mild hypothermia or normothermia (Group II). RESULTS: Fifty of 153 infants experienced moderate hypothermia after birth. Group I had lower birth weight than Group II (867.8±304.4 g vs. 1,140.3±247.5 g, P<0.001), and were younger than Group II (27.6±2.6 weeks vs. 29.1±1.9 weeks, P<0.001). Adjusted proportion of moderate to severe bronchopulmonary dysplasia (BPD) and persistent pulmonary hypertension of newborn (PPHN) were higher in Group I than in Group II (56% vs. 21.8%, P=0.005), (9.1% vs. 1.5%, P=0.019). Multiple logistic regression analysis that did not control for PPHN (model II) showed that gestational age (Odds ratio [OR] 0.93, P=0.001), moderate hypothermia (OR 4.07, P=0.013), and surgical patent ductus arteriosus (OR 4.96, P=0.023) were associated with moderate to severe BPD. Association of moderate hypothermia with moderate to severe BPD was invalid when further multiple logistic regression analysis adjusting for PPHN (model I), which had a strong association with moderate to severe BPD (OR=15.46, P=0.039), was performed. CONCLUSION: Moderate hypothermia after birth in VLBWIs was associated with PPHN and moderate to severe BPD. The association between moderate hypothermia and moderate to severe BPD might be mediated by PPHN.