Non-pathological bilious vomiting complicating therapeutic hypothermia for hypoxic ischaemic encephalopathy in neonates: a retrospective cohort study

Objective Therapeutic hypothermia (TH) for moderate-to-severe neonatal hypoxic ischaemic encephalopathy (HIE) is generally described as safe. We performed this study to determine the incidence of bilious vomiting or bilious drainage (BVD) attributable to TH in this population. Design A single-centre, retrospective cohort study. Setting Neonatal and paediatric intensive care units (NICU and PICU) of a single tertiary care centre. Patients All newborns with HIE who met criteria for TH between 2009 and 2014. Interventions Cases were matched 1:1 for unit of care (NICU vs PICU), gestational age, gender, and Sarnat score with historic controls who did not receive TH. Groups were compared with Pearson's X-2 analysis. Relative risk was calculated, and ORs were used to allow regression analysis. Results Forty-seven patients met all inclusion criteria. The incidence of BVD in patients who received TH was 26%. The group exposed to TH was more likely to experience BVD compared with the control group with a relative risk of 6.0(95% CI 1.4 to 25.4), even after accounting for improper or unchecked nasogastric position, opioids and muscle relaxant use, OR=7.8(95% CI 1.4 to 43.3), and when positive blood culture was included in the regression model, OR=11.6(95% CI 1.2 to 115.0). Three patients underwent investigation and no patients had surgical pathology. Conclusion TH appears to be associated with non-pathological bilious vomiting or gastric drainage. Further prospective data are needed to identify the patients in whom investigation and intervention may be avoided.