An assessment of nonconvulsive seizures in the intensive care unit using continuous EEG monitoring: an investigation of variables associated with mortality.

Of 49 patients with nonconvulsive seizures studied with continuous EEG monitoring, the overall mortality was 33% (16/49). Of the 23 patients with nonconvulsive status epilepticus (NCSE), 13 died (mortality 57%). Individual variables significantly associated with mortality were age, presence of NCSE, seizure duration, hospital and NICU length of stay, and delay to diagnosis and etiology (acute illness versus remote symptomatic). With multivariate logistic regression, only seizure duration (p = 0.0057, OR = 1.131/hour) and delay to diagnosis (p = 0.0351, OR = 1.039/hour) were associated with increased mortality. Acute symptomatic cases could not be adequately classified as either absence, simple, or complex partial status epilepticus when the impairment of consciousness arose form the initial illness. Current classifications of status epilepticus are inadequate for such cases.