Abstracts

Rationale: Continuous EEG (cEEG) is being increasingly used in the inpatient setting and is ordered by various clinical services. Reviewing cEEG studies is time and labor intensive, and cEEG can increase the duration of hospital stay and cost. The indications, duration, and the impact of cEEG on the clinical management when ordered by different clinical services are unclear. Methods: This is a retrospective study involving chart review of 100 patients who underwent cEEG monitoring from January to June 2018 at our center. Data regarding the ordering service, primary diagnosis, and indication for cEEG, prior routine EEG findings, duration of recording, and impact on clinical management were analyzed. Results: There were 46 males and 54 females with ages ranging from 22 to 98 years. cEEG studies were ordered in various settings including intensive care, step down and floor, and by different primary services categorized as neurology and others (neurosurgery, medical ICU, trauma, internal medicine, family medicine, cardiology, and hematology/oncology). Neurology ordered 44% of the studies followed by neurosurgery (35%) and others (21%). Indications for cEEG by neurologists versus non-neurologists were similar, including ruling out or managing seizures or convulsive/non convulsive status epilepticus, altered mental status (AMS), and abnormal body movements. Neurology ordered 6.6% of the studies for AMS compared to 33.3% by non-neurology services. Duration of cEEG (hours) by neurologists versus non-neurologists varied with the indication - ruling out seizures (16-42/20-168), management of seizures or status epilepticus (12-120/12-114), AMS (20-44/18-49), abnormal movements (12-21/17-44). 64.7% showed relevant findings that led to change in management in the first 24 hours, followed by 11.7% in 24-48 hrs. All patients had a routine EEG or an initial 30-minute EEG segment reported prior to the cEEG. In patients with AMS, no difference was seen between first 30 minutes and later cEEG. 31% of the studies revealed similar findings on cEEG compared to the prior routine study; 69% showed new findings but all were ordered for indications other than AMS. Conclusions: cEEG is a useful technique for the diagnosis and treatment of epileptic seizures and non-epileptic events. The first 24-48 hours can show clinically relevant findings that may not be seen in the initial 30 minutes of recording. Its value in patients with only altered mental status and for duration exceeding 48 hours is limited. Non-neurology services tend to order cEEG for longer duration and more often for altered mental status or ruling out seizures/status epilepticus compared to neurology. cEEG studies should be used judiciously for maximal clinical impact. Funding: No funding