Intrapartum Asphyxia and Hypoxic Ischaemic Encephalopathy in a Public Hospital: Incidence and Predictors of Poor Outcome

Objective: To determine the incidence of asphyxia and hypoxic ischaemic encephalopathy (HIE) and predictors of poor outcome in a hospital in a developing country.

Methods: Neonates of birth weight ≥ 2,000 g who required bag-and-mask ventilation and were admitted with a primary diagnosis of asphyxia from January to December 2011 were included. Medical records were retrieved and maternal and infant data collected and analysed. Infants who had severe HIE and/or died were compared with those who survived to hospital discharge with no or mild to moderate HIE.

Results: There were 21 086 liveborn infants with a birth weight of 2 000 g over the study period. The incidence of asphyxia ranged from 8.7 to 15.2/1 000 live births and that of HIE from 8.5 to 13.3/1 000, based on the definition of asphyxia used. In 60% of patients with HIE it was moderate to severe. The overall mortality rate was 7.8%. The mortality rate in infants with moderate and severe HIE was 7.1% and 62.5%, respectively. The odds of severe HIE and/or death were high if the Apgar score was <5 at 10 minutes (odds ratio (OR) 19.1; 95% confidence interval (CI) 5.7-66.9) and if there was no spontaneous respiration at 20 minutes (OR 27.2; 95% CI 6.9-117.4), a need for adrenaline (OR 81.2; 95% CI 13.2-647.7) and a pH of < 7 (OR 5.33; 95% CI 1.31-25.16). Predictors of poor outcome were Apgar score at 10 minutes (p = 0.004), need for adrenaline (p = 0.034) and low serum bicarbonate (p = 0.028).

Conclusion: The incidence of asphyxia in term and near-term infants is higher than that reported in developed countries. Apgar score at 10 minutes and need for adrenaline remain important factors in predicting poor outcome in infants with asphyxia.