The incidence of seizures in patients undergoing therapeutic hypothermia after resuscitation from cardiac arrest

Abstract

Non-convulsive seizures/status epilepticus occur in approximately 20% of comatose, non-cardiac arrest intensive care unit (ICU) patients, and are associated with increased mortality. The prevalence and clinical significance of seizures in comatose survivors of cardiac arrest undergoing therapeutic hypothermia is not well described. At this urban level I trauma center, every patient undergoing therapeutic hypothermia is monitored with continuous video encephalography (cvEEG). We abstracted medical records for all cardiac arrest patients treated with therapeutic hypothermia during 2010. Clinical data were extracted in duplicate. cvEEGs were independently reviewed for seizures by two board-certified epileptologists. There were 33 patients treated with therapeutic hypothermia after cardiac arrest in 2010 who met inclusion criteria for this study. Median age was 58 (range 28-86 years), 63% were white, 55% were male, and 9% had a history of seizures or epilepsy. During cooling, seizures occurred in 5/33 patients (15%, 95%CI 6%-33%). 11/33 patients (33%, 95% CI 19%-52%) had seizures at some time during hospitalization. 13/33 (39%) survived to discharge and of these, 7/13 (54%) survived to 30 days. 9/11 patients with seizures died during hospitalization, compared with 11/22 patients without seizures (82% vs. 50%; difference 32%, CI 951%-63%). No patient with seizures was alive at 30 days. Seizures are common in comatose patients treated with therapeutic hypothermia after cardiac arrest. All patients with seizures were deceased within 30 days of discharge. Routine use of EEG monitoring could assist in early detection of seizures in this patient population, providing an opportunity for intervention to potentially improve outcomes.