Emergency EEG: study of survival.

OBJECTIVE

To determine the survival rate according to the main findings of emergency electroencephalography (EEGs) of patients treated in a tertiary hospital.

METHOD

In this prospective study, the findings of consecutive emergency EEGs performed on inpatients in Hospital de Base in São José do Rio Preto, Brazil were correlated with survival utilizing Kaplan-Meyer survival curves.

RESULTS

A total of 681 patients with an average age of 42 years old (1 day to 96 years) were evaluated, of which 406 were male. The main reasons for EEGs were epileptic seizures (221 cases), hepatic encephalopathy [116 cases of which 85 (73.3%) were men, p-value=0.001], status epilepticus (104 cases) and impaired consciousness (78 cases). The underlying disease was confirmed in 578 (84.3%) cases with 119 (17.5%) having liver disease [91 (76.0%) were men, p-value=0.001], 105 (15.4%) suffering strokes, 67 (9.9%) having metabolic disorders, 51 (7.5%) central nervous system infections and 49 (7.2%) epilepsy. In the three months following EEG, a survival rate of 75% was found in patients with normal, discreet slow activity or intermittent rhythmic delta activity EEGs, of 50% for those with continuous delta activity and generalized epileptiform discharges, and of 25% for those with burst-suppression, diffuse depression, and in alpha/theta-pattern coma. Death was pronounced immediately in patients with isoelectric EEGs.

CONCLUSION

The main findings of EEGs, differentiated different survival rates and are thus a good prognostic tool for patients examined in emergencies.