Auditory toxicity in late preterm and term neonates with severe jaundice

Jaundice may cause auditory toxicity (auditory neuropathy and hearing loss). However, total serum bilirubin (TSB) does not discriminate neonates at risk for auditory toxicity. We compared TSB, bilirubin:albumin molar ratio (BAMR), and unbound bilirubin for their association with auditory toxicity in neonates with severe jaundice (TSB ≥342μmol/L, or that met exchange transfusion).

Neonates greater or equal to 34 weeks gestational age with severe jaundice during the first 2 postnatal weeks were eligible for prospective cohort study, unless they had craniofacial malformations, chromosomal disorders, toxoplasmosis, other infections, rubella, cytomegalovirus, herpes simplex infections, surgery, or family history of congenital deafness.

Twenty-eight out of 100 neonates (mean gestational age 37.4wks; 59 males, 41 females) had auditory toxicity. Peak unbound bilirubin, but not peak TSB and BAMR, was associated with auditory toxicity (p<0.05) in neonates with severe (TSB <427.5μmol/L) and extreme hyperbilirubinemia (TSB ≥427.5μmol/L). Area under the receiver operating characteristic curve for unbound bilirubin (0.78) was significantly greater (p=0.03) than TSB (0.54) among neonates with severe but not extreme hyperbilirubinemia.

Unbound bilirubin is more strongly associated with auditory toxicity than TSB and/or BAMR in greater or equal to 34 weeks gestational age neonates with severe jaundice. Unbound bilirubin is a better predictor than TSB in neonates with severe hyperbilirubinemia.