Brainstem auditory evoked potentials in icteric fullterm newborns: alterations after exchange transfusion

Area of Science:

• Neonatal Neurology
• Auditory Neurophysiology
• Bilirubin Metabolism

Background:

• Hyperbilirubinemia in newborns can lead to bilirubin neurotoxicity.
• Brainstem auditory evoked potentials (BAEP) are sensitive indicators of auditory pathway function.
• The impact of acute bilirubin reduction on neonatal BAEP requires further investigation.

Purpose of the Study:

• To evaluate changes in BAEP following acute decreases in bilirubin levels via exchange transfusion (ET).
• To assess the reversibility of bilirubin-induced neurotoxicity on auditory pathways.
• To explore the relationship between bilirubin levels and BAEP alterations in newborns.

Main Methods:

• BAEP were recorded in five full-term newborns with hyperbilirubinemia (ABO incompatibility) before, during, and at 1, 24, and 48 hours after ET.
• Newborns had no other risk factors known to affect BAEP.
• BAEP parameters, including latencies I, V, and interpeak latency V-III, were analyzed and compared to laboratory data.

Main Results:

• Pre-ET recordings showed significant differences in latencies I, V, and interpeak latency V-III compared to normal data.
• Post-ET, a trend towards shortened latencies and interpeak latencies correlated with decreased bilirubin levels was observed.
• Predominant post-ET alterations included shortening of wave V latency and wave V-I interval; these changes were linked to bilirubin variations in four patients.

Conclusions:

• Bilirubin neurotoxicity, as indicated by BAEP alterations, appears to be rapidly reversible following exchange transfusion.
• Even moderate increases in bilirubin can deleteriously influence neonatal BAEP, impacting the determination of neurotoxicity thresholds.
• Follow-up BAEP assessments are crucial for hyperbilirubinemic newborns to monitor the effects and reversibility of bilirubin-induced neurotoxicity.