Abstracts

Rationale: In recent years, continuous EEG (cEEG) with accompanying video monitoring has been increasingly recognized as a powerful non-invasive tool for the monitoring of cerebral function in critically ill patients. Whether the results of cEEG impact clinical decision making is not clear. The purpose of this study was to review the utilization of cEEG in our ICU, and to determine whether or not clinical decisions were made based on cEEG results. Methods: This study was a retrospective review of a total of 52 continuous EEGs performed in a 32-bed ICU for the period of January 2008 to June 2013. Pediatric patients (age <18 years) were excluded from the study. All EEGs were initially read by one of two neurologists certified in EEG by the Canadian Society of Clinical Neurophysiology (AES and DGB). A third neurologist certified by the CSCN (LBL) was blinded to the patient's clinical history and subsequently re-read the EEGs and provided a comprehensive report. The two reports were compared. When they differed, the initial assessment was used for data collection. Results: 52 cEEGs were performed during the study period. The most common indication for cEEG was to rule out non-convulsive seizure or status epilepticus (51.9%; n=27). Within this group, epileptiform activity was detected in 55.6% of patients and its presence led to a change in clinical management in almost all patients (93.3%). Other indications for cEEG included monitoring during hypothermia after cardiac arrest (15.4%, n=8), clinical activity suspicious for seizure (21.2%; n=11), and unexplained decreased LOC (9.6% n=5). In patients who displayed clinical activity suspicious for seizure, an event was captured in 73% of patients. Interestingly, none of these events correlated with electrographic epileptiform activity. This absence of epileptiform activity led to a change in management in 75% of patients, usually weaning of sedation and/or anticonvulsant medications. Among all patients who had withdrawal of life support, cEEG data was used as part of the decision process in 32%. Common findings in these cEEG were epileptiform activity, burst suppression pattern, and lack of reactivity. Conclusions: In our centre, cEEG appears to contribute to clinical decision making, including the titration of sedation and anticonvulsant medications, as well as withdrawal of life support. Interestingly, physicians and nurses have a great deal of difficulty differentiating non-epileptic movements from seizures, and cEEG assists in this differentiation. Larger, prospective studies are required to validate these findings.