Researchers at the Mayo Clinic, Rochester, MN studied the outcome and identified prognostic factors for refractory status epilepticus (RSE) in 54 adult patients, median age 52 years [range 18-93]. RSE was defined as generalized convulsive or nonconvulsive status epilepticus that continued despite initial first and second-line therapies. Patients younger than 18 years, anoxic/myoclonic, psychogenic, simple partial, and absence SE were excluded. Of 63 consecutive episodes of RSE, anesthetic agents were used in 55 (87.3%). Duration of drug-induced coma was a mean of 11 days (SD 17.9 days). Cardiac arrhythmias occurred in 21 of 60 episodes (35%) and required intervention in 14 of 21 cases (66.67%). In hospital mortality was 31.75%, in 20 of 63 episodes. Functional outcome at discharge was poor in 48 (76.19%) episodes. Hospital length of stay was a mean of 27.7 days (SD 37.3 days). Poor functional outcome was associated with drug-induced coma (p=0.03), cardiac arrhythmias requiring intervention (p=0.01), and pneumonia (p=0.01). Prolonged mechanical ventilation was associated with mortality (p=0.04). Good functional recovery (p=0.01) followed seizure control without suppression-burst or isoelectric EEG. Functional outcome was not related to age, history of epilepsy, previous SE, type of SE, and anesthetic drug used. 
COMMENT. In adults with refractory status epilepticus, risk factors for a poor prognosis include the severity of the SE, the need for drug-induced coma, cardiopulmonary complications requiring prolonged mechanical ventilation, and pneumonia. Aggressive EEG suppression does not improve outcome of RSE. Three-quarters of adult RSE patients have a poor outcome.
A review of studies of status epilepticus published from 1990-2009 shows that children have a better prognosis than adults, and age and depth of coma are the strongest predictors of outcome of SE . In otherwise normal children with focal epilepsy, SE has no significant effect on long-term intellectual and seizure outcome.