Abstracts

Rationale: Continuous EEG (cEEG) is increasingly employed to assess brain function in critically ill patients. The indications for cEEG, as proposed by the American Clinical Neurophysiology Society (ACNS), include diagnosis of seizures and/or status epilepticus, identification of cerebral ischemia in high risk patients, assessment of level of consciousness in sedated patients, and post-cardiac arrest prognostication. While cEEG identifies seizures in 8-48% of critically ill patients who undergo monitoring and often informs treatment decisions, the impact of cEEG on clinical outcomes in this patient population is not well established.  We aimed to characterize utilization of cEEG over time as the first step in elucidating the impact of cEEG use on clinical outcomes.  Methods: We performed a retrospective cross-sectional study using the National Inpatient Sample (NIS) from 2004 to 2013. We sampled the population of adult patients who received intensive care during their hospitalization through use of the ICD-9 procedure code for mechanical ventilation (96.7x). Within this sample, we identified patients who underwent cEEG at some point during their admission (89.19). We examined patient subgroups by primary discharge diagnosis of seizure, status epilepticus, subarachnoid hemorrhage, coma, and cardiac arrest. Results: From 2004 to 2013, a total of 7,896,064 critically ill patients were identified, of which 26,660 patients received cEEG. Over this time period, there was a marked increase in the proportion of mechanically ventilated patients who received cEEG from 0.064% (95%CI 0.033-0.095) to 0.835% (95%CI 0.654-1.015). Growth in cEEG utilization was observed across all primary discharge diagnoses (Figure 1). cEEG was most frequently employed for patients with a primary discharge diagnosis of status epilepticus- up to 7.72% of patients by 2013.   Conclusions: There was a greater than ten-fold increase in cEEG utilization from 2004 to 2013. The next step will be to investigate the how use of cEEG impacts the outcomes of mortality, discharge disposition, and length of stay with consideration of patient-specific and hospital-specific characteristics. Funding: National Institute of Neurological Disorders and Stroke (NINDS) T32 Award in Neurologic Clinical Epidemiology