Standardized EEG interpretation accurately predicts prognosis after cardiac arrest

Abstract

Objective:To identify reliable predictors of outcome in comatose patients after cardiac arrest using a single routine EEG and standardized interpretation according to the terminology proposed by the American Clinical Neurophysiology Society.Methods:In this cohort study, 4 EEG specialists, blinded to outcome, evaluated prospectively recorded EEGs in the Target Temperature Management trial (TTM trial) that randomized patients to 33°C vs 36°C. Routine EEG was performed in patients still comatose after rewarming. EEGs were classified into highly malignant (suppression, suppression with periodic discharges, burst-suppression), malignant (periodic or rhythmic patterns, pathological or nonreactive background), and benign EEG (absence of malignant features). Poor outcome was defined as best Cerebral Performance Category score 3–5 until 180 days.Results:Eight TTM sites randomized 202 patients. EEGs were recorded in 103 patients at a median 77 hours after cardiac arrest; 37% had a highly malignant EEG and all had a poor outcome (specificity 100%, sensitivity 50%). Any malignant EEG feature had a low specificity to predict poor prognosis (48%) but if 2 malignant EEG features were present specificity increased to 96% (p < 0.001). Specificity and sensitivity were not significantly affected by targeted temperature or sedation. A benign EEG was found in 1% of the patients with a poor outcome.Conclusions:Highly malignant EEG after rewarming reliably predicted poor outcome in half of patients without false predictions. An isolated finding of a single malignant feature did not predict poor outcome whereas a benign EEG was highly predictive of a good outcome.

Targeted temperature management and neuroprognostication after cardiac arrest: A survey in Belgium

“…Indeed, studies using continuous EEG monitoring and consensus definitions have shown that EEG had the best predictive value at 12 and 24 h after ROSC [40,42,43]. A normal voltage, continuous EEG devoid of periodic or epileptiform discharges (referred to as ''benign'' EEG) at 12 h or, to a lesser extent, at 24 h after ROSC is most often associated with good recovery [42] (Fig. 1a).…”

“…1a). On the contrary, a suppressed (\10 lV) or suppression-burst (including generalized periodic discharges on a suppressed background) background (referred to as ''highly malignant'' EEG) at 24 h is associated with lack of neurological recovery [42][43][44] (Fig. 1b-e).…”

Multimodal Outcome Prognostication After Cardiac Arrest and Targeted Temperature Management: Analysis at 36 °C

“…Specifically, bilateral absence of brainstem reflexes, absence of motor response to pain and treatmentresistant myoclonus (7-10) unreactive or discontinuous EEG background activity (10)(11)(12) bilateral absence of N20 Somatosensory Evoked Potentials (SSEP) (7) and high serum Neuron Specific Enolase (NSE) (13) are related to poor neurological recovery.…”

Serum tau and neurological outcome in cardiac arrest

“…Some methods, notably SSEP, have high specificity to predict poor outcome but limited sensitivity to identify patients with severe brain injury 5. Other methods, such as EEG6 and neuroimaging,7 appear more sensitive but may be prone to interpreter variability 8…”