Carboxyhemoglobin as an early predictor for pathological hyperbilirubinemia in preterm neonates

Background Hyperbilirubinemia is the most common condition requiring evaluation and treatment in newborns. Approximately 60% of term and 80% of preterm babies develop jaundice in the first week of life. Objectives To assess the role of carboxyhemoglobin (COHb) as an early predictor for pathological hyperbilirubinemia in preterm neonates. Patients and methods This prospective cohort study was conducted on 74 preterm newborns of less than 37 weeks gestation of both sexes, admitted in the first day of life at the neonatal ICU of Menoufia University Hospital from August 2019 to August 2020. All included newborns had serum COHb percentage and total serum bilirubin levels measured just after admission and then were followed up for developing pathological hyperbilirubinemia for 72 h. The case group included 40 preterm neonates who developed pathological hyperbilirubinemia from 24 to 72 h of life while the control group included 34 preterm neonates who did not develop pathological hyperbilirubinemia within the first 72 h of life. Results Both COHb percentage and total serum bilirubin level just after admission were significantly higher in cases than in controls (COHb 1.14 ± 0.28% in cases vs. 0.82 ± 0.22 in controls with P < 0.001). Receiver-operating characteristic case analysis showed that the cutoff point of COHb percentage just after admission more than 1.13% had 77.5% sensitivity and 80.2% specificity for cases with significant neonatal hyperbilirubinemia. Conclusion Serum COHb percentage at admission is a sensitive and specific method to predict preterm neonates who will develop pathological hyperbilirubinemia.