37 studies (2403 patients) were included. A bilaterally absent N20 SSEP wave during TH (4 studies; QOE: Moderate) or after rewarming (5 studies; QOE: Low), a nonreactive EEG background (3 studies; QOE: Low) after rewarming, a combination of absent pupillary light and corneal reflexes plus a motor response no better than extension (M ¡Ü 2) (1 study; QOE: Very low) after rewarming predicted CPC 3-5 with 0 % FPR and narrow (<10 % ) 95 % confidence intervals. No consistent threshold for 0 % FPR could be identified for blood levels of biomarkers. In 6/8 studies on SSEP, in 1/3 studies on EEG reactivity and in the single study on clinical examination the investigated predictor was used for decisions to withdraw treatment, causing the risk of a self-fulfilling prophecy.
in the first 7 days after CA, a bilaterally absent N20 SSEP wave anytime, a nonreactive EEG after rewarming or a combination of absent ocular reflexes and M ¡Ü 2 after rewarming predicted CPC 3-5 with 0 % FPR and narrow 95 % CIs, but with a high risk of bias.