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

Abstract

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.