Lidocaine response rate in aEEG ‐confirmed neonatal seizures: Retrospective study of 413 full‐term and preterm infants

Summary Objective To investigate the seizure response rate to lidocaine in a large cohort of infants who received lidocaine as second‐ or third‐line antiepileptic drug ( AED ) for neonatal seizures. Methods Full‐term (n = 319) and preterm (n = 94) infants, who received lidocaine for neonatal seizures confirmed on amplitude‐integrated EEG (aEEG), were studied retrospectively (January 1992–December 2012). Based on aEEG findings, the response was defined as good (>4 h no seizures, no need for rescue medication); intermediate (0–2 h no seizures, but rescue medication needed after 2–4 h); or no clear response (rescue medication needed <2 h). Results Lidocaine had a good or intermediate effect in 71.4%. The response rate was significantly lower in preterm (55.3%) than in full‐term infants (76.1%, p < 0.001). In full‐term infants the response to lidocaine was significantly better than midazolam as second‐line AED (21.4% vs. 12.7%, p = 0.049), and there was a trend for a higher response rate as third‐line AED (67.6% vs. 57%, p = 0.086). Both lidocaine and midazolam had a higher response rate as third‐line AED than as second‐line AED (p < 0.001). Factors associated with a good response to lidocaine were the following: higher gestational age, longer time between start of first seizure and administration of lidocaine, lidocaine as third‐line AED , use of new lidocaine regimens, diagnosis of stroke, use of digital aEEG , and hypothermia. Multivariable analysis of seizure response to lidocaine included lidocaine as second‐ or third‐line AED and seizure etiology. Significance Seizure response to lidocaine was seen in ~70%. The response rate was influenced by gestational age, underlying etiology, and timing of administration. Lidocaine had a significantly higher response rate than midazolam as second‐line AED , and there was a trend for a higher response rate as third‐line AED . Both lidocaine and midazolam had a higher response rate as third‐line compared to second‐line AED , which could be due to a pharmacologic synergistic mechanism between the two drugs.