Abstract
Methemoglobinemia is a rare but potentially serious complication of lidocaine (LDC) use for local anesthesia in infants and young children, yet its prevalence during continuous systemic infusion for neonatal seizures remains unclear. Given the increasing use of LDC as add-on therapy for neonatal seizures, this retrospective cohort study evaluated methemoglobin (MetHb) levels in 51 neonates with (serial) measurements within 96 h before and after LDC infusion. Methemoglobinemia was defined as MetHb > 2% in arterial or capillary blood gas samples. Prevalence increased from 6% (3/51) before LDC to 47% (24/51) after administration (p < 0.001). Most neonates had mildly elevated MetHb levels (< 5%); three had a MetHb level > 5%, with a highest peak of 9.5%. In one neonate LDC was discontinued due to hypoxemia, the others were asymptomatic. In neonates who developed methemoglobinemia after LDC, the mean time to peak MetHb was 29.1 h (95% CI 11.1-73.3), and mean time to recover to < 2% after the peak was 27.5 h (95% CI 8.4-75.5). Over half of neonates receiving regimen III (> 36 weeks without therapeutic hypothermia [TH]) developed methemoglobinemia, compared to none on regimen IV (with TH). This suggests an association with a higher cumulative dose and longer infusion duration.Conclusion: In conclusion, methemoglobinemia occurred in nearly half of neonates receiving continuous LDC for seizures and was associated with the dosing regimen. It is important to be aware of this complication, especially in infants who develop respiratory deterioration and oxygenation problems following continuous LDC administration.