Multimodal Prediction of Favorable Outcome After Cardiac Arrest: A Cohort Study

Objectives: Prognostic guidelines after cardiac arrest (CA) focus on unfavorable outcome prediction; favorable outcome prognostication received less attention. Our aim was to identify favorable outcome predictors and combine them into a multimodal model.

Design: Retrospective analysis of prospectively collected data (January 2016 to June 2021).

Setting: Two academic hospitals (Centre Hospitalier Universitaire Vaudois, Lausanne, Switzerland; Brigham and Women's Hospital, Boston, MA).

Patients: Four hundred ninety-nine consecutive comatose adults admitted after CA.

Interventions: None.

Measurements and main results: CA variables (initial rhythm, time to return of spontaneous circulation), clinical examination (Full Outline of UnResponsiveness [FOUR] score at 72 hr, early myoclonus), electroencephalography (EEG) (reactivity, continuity, epileptiform features, and prespecified highly malignant patterns), somatosensory-evoked potentials, quantified pupillometry, and serum neuron-specific enolase (NSE) were retrieved. Neurologic outcome was assessed at 3 months using Cerebral Performance Category (CPC); 1 and 2 were considered as favorable outcome. Predictive performance of each variable toward favorable outcomes were calculated, and most discriminant items were combined to obtain a multimodal prognostic score, using multivariable ordinal logistic regression, receiving operator characteristic curves, and cross-validation. Our analysis identified a prognostic score including six modalities (1 point each): 1) early (12-36 hr) EEG not highly malignant, 2) early EEG background reactivity, 3) late (36-72 hr) EEG background reactivity and 4) continuity, 5) peak serum NSE within 48 hours less than or equal to 41 µg/L, and 6) FOUR score greater than or equal to 5 at 72 hours. At greater than or equal to 4 out of 6 points, sensitivity for CPC 1-2 was 97.5% (95% CI, 92.9-99.5%) and accuracy was 77.5% (95% CI, 72.7-81.8%); area under the curve was 0.88 (95% CI, 0.85-0.91). The score showed similar performances in the validation cohort.

Conclusions: This study describes and externally validates a multimodal score, including clinical, EEG and biological items available within 72 hours, showing a high performance in identifying early comatose CA survivors who will reach functional independence at 3 months.