Seizures and risks for recurrence in critically ill patients: an observational cohort study

Background To assess the frequency and clinical characteristics of seizures in adult critically ill patients, to identify predictors of recurrent seizures not transforming into status epilepticus and to characterize their effects on course and outcome. Methods ICU patients at a Swiss academic medical center with seizures not transforming into status epilepticus from 2015 to 2020 were included. Recurrent seizures and associated clinical characteristics were primary, death, and return to premorbid neurologic function were secondary outcomes. Results Two hundred of 26,370 patients (0.8%) with a median age of 65 years had seizures during ICU stay. Seizure semiology was described in 82% (49% generalized; 33% focal) with impaired consciousness during seizures in 80% and motor symptoms in 62%. Recurrent seizures were reported in 71% (36% on EEG) and associated with longer mechanical ventilation (p = 0.031), higher consultation rate by neurologists (p < 0.001), and increased use of EEG (p < 0.001) when compared to single seizures. The use of EEG was not associated with secondary outcomes. Acidosis at seizure onset and prior emergency operations were associated with decreased odds for seizure recurrence (OR 0.43; 95% CI 0.20-0.94 and OR 0.48; 95% CI 0.24-0.97). Epilepsy had increased odds for seizure recurrence (OR 3.56; 95% CI 1.14-11.16). Conclusions Seizures in ICU patients are infrequent, but mostly recurrent, and associated with higher resource utilization. Whenever seizures are observed, clinicians should be vigilant about the increased risk of seizures recurrence and the need for antiseizure treatment must be carefully discussed. While known epilepsy seems to promote recurrent seizures, our results suggest that both acidosis and previous emergency surgery seem to have protective/antiseizure effects.