The CAHP (Cardiac Arrest Hospital Prognosis) SCORE: Predicting neurological outcome after out-of-hospital cardiac arrest

Background: Out-of-hospital cardiac arrest (OHCA) carries a very poor prognosis. Early prognostication of patients admitted in ICU after resuscitated OHCA is a key issue but remains challenging. The aim of that study was to establish a new scoring system to predict poor neurological outcome in these patients. Materials and Methods: The CAHP (Cardiac Arrest Hospital Prognosis) score was developed from the Sudden Death Expertise Center registry (SDEC, Paris, France). Objective risk factors were weighted on the basis of a logistic regression analysis. The primary outcome was poor neurological outcome defined as Cerebral Performance Category 3, 4 or 5. Thresholds were defined to distinguish low, moderate and high-risk groups. The CAHP score was then validated in an external dataset (Parisian OHCA Registry). Score calibration and discrimination characteristics were assessed in the validation dataset. Results: The developmental dataset included 819 patients admitted in ICU from May 2011 to December 2012. After logistic regression, 7 variables were independently associated with poor neurological outcome: age, initial shockable rhythm, time form collapse to basic life support (BLS), time from BLS to return of spontaneous circulation (ROSC), location of cardiac arrest, epinephrine dose during resuscitation and arterial pH at admission. These variables were included in the CAHP score. 3 risks groups were identified: a low risk group (score ≤ 150, 39 % of unfavorable outcome), medium risk group (score 150-200, 81% of unfavorable outcome) and high-risk group (CAHP score ≥ 200, 100 % of unfavorable outcome). AUC of the CAHP score was 0.93. In the external validation dataset, discrimination value of the CAHP score was consistent with an AUC of 0.85. Conclusion: The CAHP score is a simple and objective tool for early assessment of prognosis in patients admitted to ICU after OHCA. Moreover it allows to stratify the probability of poor neurological outcome by identifying a very high-risk category of patients (score ≥ 200).