Abstract
Epileptiform electroencephalographic (EEG) patterns are common after resuscitation from cardiac arrest, are associated with patient outcome, and may require treatment. It is unknown whether continuous EEG monitoring is needed to detect these patterns or if brief intermittent monitoring is sufficient. If continuous monitoring is required, the necessary duration of observation is unknown. To quantify the time-dependent sensitivity of continuous EEG for epileptiform event detection, and to compare continuous EEG to several alternative EEG-monitoring strategies for post-cardiac arrest outcome prediction. This observational cohort study was conducted in 2 academic medical centers between September 2010 and January 2018. Participants included 759 adults who were comatose after being resuscitated from cardiac arrest and who underwent 24 hours or more of EEG monitoring. Epileptiform EEG patterns associated with neurological outcome at hospital discharge, such as seizures likely to cause secondary injury. Overall, 759 patients were included in the analysis; 281 (37.0%) were female, and the mean (SD) age was 58 (17) years. Epileptiform EEG activity was observed in 414 participants (54.5%), of whom only 26 (3.4%) developed potentially treatable seizures. Brief intermittent EEG had an estimated 66% (95% CI, 62%-69%) to 68% (95% CI, 66%-70%) sensitivity for detection of prognostic epileptiform events. Depending on initial continuity of the EEG background, 0 to 51 hours of monitoring were needed to achieve 95% sensitivity for the detection of prognostic epileptiform events. Brief intermittent EEG had a sensitivity of 7% (95% CI, 4%-12%) to 8% (95% CI, 4%-12%) for the detection of potentially treatable seizures, and 0 to 53 hours of continuous monitoring were needed to achieve 95% sensitivity for the detection of potentially treatable seizures. Brief intermittent EEG results yielded similar information compared with continuous EEG results when added to multivariable models predicting neurological outcome. Compared with continuous EEG monitoring, brief intermittent monitoring was insensitive for detection of epileptiform events. Monitoring EEG results significantly improved multimodality prediction of neurological outcome, but continuous monitoring appeared to add little additional information compared with brief intermittent monitoring.
Highlights
Sudden cardiac arrest affects more than 600 000 individuals in the US each year.1 Most patients hospitalized after resuscitation from cardiac arrest are initially comatose,2,3 and of these, 25% to 50% have electroencephalographic (EEG) activity on the ictal-interictal continuum.4-6 Patients who develop epileptiform EEG activity generally have worse clinical outcomes.5,7-11 It remains controversial whether this association reflects a causal relationship mediated by secondary brain injury, as has been observed in other disease states,12-14 or if abnormal EEG findings are a marker of primary injury severity.15 Regardless, most clinicians treat convulsive or nonconvulsive status epilepticus when detected.16-19 In short, EEG findings have established prognostic value, and detection of EEG abnormalities may alter clinical care
Compared with continuous EEG monitoring, brief intermittent monitoring was insensitive for detection of epileptiform events
Monitoring EEG results significantly improved multimodality prediction of neurological outcome, but continuous monitoring appeared to add little additional information compared with brief intermittent monitoring
Summary
Sudden cardiac arrest affects more than 600 000 individuals in the US each year. Most patients hospitalized after resuscitation from cardiac arrest are initially comatose, and of these, 25% to 50% have electroencephalographic (EEG) activity on the ictal-interictal continuum. Patients who develop epileptiform EEG activity generally have worse clinical outcomes. It remains controversial whether this association reflects a causal relationship mediated by secondary brain injury, as has been observed in other disease states, or if abnormal EEG findings are a marker of primary injury severity. Regardless, most clinicians treat convulsive or nonconvulsive status epilepticus when detected. In short, EEG findings have established prognostic value, and detection of EEG abnormalities may alter clinical care. Most patients hospitalized after resuscitation from cardiac arrest are initially comatose, and of these, 25% to 50% have electroencephalographic (EEG) activity on the ictal-interictal continuum.. Patients who develop epileptiform EEG activity generally have worse clinical outcomes.. Patients who develop epileptiform EEG activity generally have worse clinical outcomes.5,7-11 It remains controversial whether this association reflects a causal relationship mediated by secondary brain injury, as has been observed in other disease states, or if abnormal EEG findings are a marker of primary injury severity.. EEG findings have established prognostic value, and detection of EEG abnormalities may alter clinical care. Based on these facts, consensus guidelines strongly recommend that patients who are comatose after cardiac arrest undergo frequent or continuous EEG monitoring.
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