Abstracts

Rationale: Emergent/stat electroencephalogram (sEEG) is a tool utilized to identify patients in non-convulsive status epilepticus (NCSE), especially in patients with unexplained mental status change. Previous smaller studies have evaluated the indications and usefulness of sEEG [1-2], with some arguing that neurological consultation is needed prior to obtaining a sEEG [3]. The primary objective of our study was to evaluate the utility of sEEG in detecting discrete seizures or status epilepticus as a function of ordering physician and clinical indication. Methods: We performed a retrospective review of all sEEGs reports at the Barrow Neurological Institute for the year 2008. sEEG is available 24 hours a day and are performed at the request of any ordering physician, except between 6 PM to 6 AM, and on weekends, when they must first be approved by a clinical neurophysiologist. All reports were reviewed for the parameters listed in Table 1. Statistical analysis was performed using either chi-squared or Fisher s exact test. Results: Of the 3,471 inpatient EEGs performed in our institution during the review period, 778 (22.4%) were sEEGs. Patients ranged in age from 4 days to 95 years (median age of 54 years). 49% of the patients were male. 3.5% (n=27) of all sEEGs demonstrated NCSE, while 0.4% (n=3) and 1.2% (n=9) revealed convulsive status epilepticus or discrete electrographic seizures, respectively (table 1). Although our volume has since increased by 7-fold, this yield did not differ significantly from 2005 data obtained at our institution [4]. Neurologist had the highest rate of finding status epilepticus (SE) or seizures at 7.3%, followed by intensivists (7%), neurosurgeons (4.1%), and other services (3.3%). However, there was no statistically significant difference among ordering physicians (p=0.20). The most useful clinical indicators for predicting SE or seizure were overt, continuous seizures and witnessed seizure without return to baseline (p<0.001)(table 2). Conclusions: In our tertiary care institution sample, the rate of finding SE or seizures among sEEG is 5.1%. In our sample, the best clinical predictors of finding NCSE or discrete seizures on a sEEG are overt, continuous seizures or witnessed seizure without return to baseline. Additional monitoring methods, such as continuous EEG, should be considered in critically ill patients for improved yield. Furthermore, our data suggests that perhaps neurological consultation should NOT be mandatory prior to obtaining a sEEG. References: 1. Towne AR, Waterhouse EJ, Boggs JG et al. Prevalence of nonconvulsive status epilepticus in comatose patients. Neurology 2000; 54:340-345. 2. Varelas PN, Spanaki MV, Hacein-Bey L et al. Emergent EEG: indications and diagnostic yield. Neurology 2003; 61:702-704. 3. Benbadis SR. Use and abuse of stat EEG. Expert Review of Neurotherapeutics 2008; 8(6): 865-868. 4. Shareef YS, Chung S, Ros-Escalante J, Williams P (2006). Utilization of Stat EEG To Evaluate Possible Subtle Status Epilepticus. American Epilepsy Society meeting abstracts, Abstract #1.073.