Standardized EEG interpretation accurately predicts prognosis after cardiac arrest

Neurology. 2016 Apr 19;86(16):1482-90. doi: 10.1212/WNL.0000000000002462. Epub 2016 Feb 10.

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.

Publication types

  • Randomized Controlled Trial

MeSH terms

  • Aged
  • Anticonvulsants / therapeutic use
  • Body Temperature
  • Brain / physiopathology*
  • Comorbidity
  • Electroencephalography*
  • Female
  • Follow-Up Studies
  • Heart Arrest / diagnosis*
  • Heart Arrest / physiopathology*
  • Heart Arrest / therapy
  • Humans
  • Hypnotics and Sedatives / therapeutic use
  • Hypothermia, Induced
  • Male
  • Prognosis
  • Seizures / diagnosis
  • Seizures / physiopathology
  • Seizures / therapy
  • Sensitivity and Specificity
  • Severity of Illness Index
  • Single-Blind Method
  • Time Factors
  • Treatment Outcome

Substances

  • Anticonvulsants
  • Hypnotics and Sedatives