Digital video-electroencephalographic monitoring in the neurological-neurosurgical intensive care unit: clinical features and outcome

Abstract

Background: Prolonged electroencephalographic (EEG) recordings in the neurological-neurosurgical intensive care unit (NICU) may be performed in patients with status epilepticus, repetitive seizure activity, or an encephalopathy with or without seizures. The electroclinical correlation and neurological outcome of patients undergoing digital video-EEG monitoring (DVEEG) in the NICU has not been determined.

Objectives: To evaluate the clinical utility and prognostic importance of the DVEEG in the NICU.

Methods: We retrospectively evaluated 105 patients who underwent DVEEG in the NICU at the Mayo Clinic, Rochester, Minn, between January 1, 1994, and July 31, 2001. All patients had a routine EEG recording performed prior to DVEEG.

Results: The mean age of the patients at the time of the DVEEG was 54 years (age range, 16-88 years). The mean duration of the DVEEG was 2.9 days (range, 1-17 days). Forty-four patients (42%) had a severe encephalopathy (Glasgow Coma Scale score, <8) at the time of the DVEEG. Forty-five patients (42.8%) had generalized convulsive status epilepticus, 19 patients (18.1%) had nonconvulsive status epilepticus, and 7 patients (6.7%) had epilepsia partialis continua. The mean duration of follow-up was 7 months (range, 1-54 months). The outcome in 84 patients included death in 38 patients, severe neurological deficits, that is, bed bound and needs support for activities of daily living, in 6 patients, and a vegetative state in 3 patients. Fifteen individuals had no neurological impairment during follow-up. Refractory status epilepticus (P<.003), hypoxic-ischemic encephalopathy (P<.004), and multiple cerebral infarcts (P<.003) were the factors associated with increased mortality in univariate analysis. With multivariate logistic regression analysis only the presence of multiple strokes (P<.03; odds ratio, 5.62) was predictive of mortality.

Conclusions: Continuous EEG monitoring is essential in the diagnosis and treatment of refractory status epilepticus or an encephalopathy with seizures in the NICU. A minority of these patients, however, experienced a favorable neurological outcome.