Vigintiphobia, Unbound Bilirubin, and Auditory Brainstem Responses

Abstract

Objective. The management of nonhemolytic hyperbilirubinemia in term newborns is controversial. To evaluate the usefulness of serum unbound bilirubin concentrations (UBCs) in the management of hyperbilirubinemia, we compared the concentrations with abnormal auditory brainstem responses (ABRs). Methods. ABRs and serum UBCs in 37 hyperbilirubinemic term newborns (total bilirubin concentrations [TBCs] ≥20 mg/dL and direct bilirubin concentrations <2 mg/dL) were measured before treatment with either phototherapy or exchange transfusions. Eight of these newborns had blood incompatibilities. These hyperbilirubinemic newborns were divided into three groups according to the findings of ABR: group A, normal ABR (n = 18); group B, prolonged latency of wave I only (n = 8); and group C, prolonged interpeak latency of wave I-III/I-V and/or poor amplitude (n = 11). Results. The peak TBC was significantly different between groups A and C (22.8 ± 2.2 mg/dL and 25.4 ± 2.5 mg/dL, respectively; P < .05), though there were no differences between groups A and B and between groups B and C. The peak UBCs in groups B (1.27 ± 0.7 µg/dL) and C (1.34 ± 0.37 µg/dL) were significantly higher than in group A (0.78 ± 0.26 µg/dL) (P < .05 and P < .01, respectively), though there was no significant difference in the peak UBC between groups B and C. Abnormal ABR findings were more clearly associated with the level of UBC at 1.0 µg/dL than that of TBC at 23 mg/dL by multiple logistic regression analysis (odds ratio 16.6, P = .0026, vs 4.2, P = .1272). Conclusions. These results suggest that measuring UBC may help in evaluating the possible risk of bilirubin encephalopathy in full-term newborns when there is vigintiphobia (fear of 20).