The CAHP (Cardiac Arrest Hospital Prognosis) score: a tool for risk stratification after out-of-hospital cardiac arrest

Aims: Survival after out-of-hospital cardiac arrest (OHCA) remains disappointingly low. Among patients admitted alive, early prognostication remains challenging. This study aims to establish a stratification score for patients admitted in intensive care unit (ICU) after OHCA, according to their neurological outcome.

Methods and results: The CAHP (Cardiac Arrest Hospital Prognosis) score was developed from the Sudden Death Expertise Center registry (Paris, France). The primary outcome was poor neurological outcome defined as Cerebral Performance Category 3, 4, or 5 at hospital discharge. Independent prognostic factors were identified using logistic regression analysis and thresholds defined to stratify low-, moderate-, and high-risk groups. The CAHP score was validated in both a prospective and an external data set (Parisian Cardiac Arrest Registry). The developmental data set included 819 patients admitted from May 2011 to December 2012. After multivariate analysis, seven variables were independently associated with poor neurological outcome and subsequently included in the CAHP score (age, non-shockable rhythm, time from collapse to basic life support, time from basic life support to return of spontaneous circulation, location of cardiac arrest, epinephrine dose, and arterial pH). Three risks groups were identified: low risk (score ≤150, 39% of unfavourable outcome), medium risk (score 150-200, 81% of unfavourable outcome) and high-risk group (score ≥200, 100% of unfavourable outcome). The AUC of the CAHP score were 0.93, and the discrimination value in the validation data sets was consistent (respectively, AUC 0.91 and 0.85).

Conclusion: The CAHP score represents a simple tool for early stratification of patients admitted in ICU after OHCA. A high-risk category of patients with very poor prognosis can be easily identified.