External validation of Pittsburgh Cardiac Arrest Category illness severity score

Early prognostication post-cardiac arrest can help determine appropriate medical management and help evaluate effectiveness of post-arrest interventions. The Pittsburgh Cardiac Arrest Category (PCAC) severity score is a 4-level illness severity score found to strongly predict patient outcomes in both in- (IHCA) and out-of-hospital cardiac arrests (OHCA). We aimed to validate the PCAC severity score in an external cohort of cardiac arrest patients.

We retrospectively assigned PCAC scores to both IHCA and OHCA patients treated by our hypothermia team from July 1, 2009 to July 1 2016. Our primary outcome was survival to hospital discharge. Secondary outcomes were favorable functional status defined as favorable discharge disposition (home or acute rehabilitation), discharge Cerebral Performance Category (CPC); and discharge modified Rankin Scale (mRS). We tested the association of PCAC and outcomes using a multivariable adjusted logistic regression model.

We included 317 subjects in our model. PCAC was strongly associated with survival I Reference; II adjusted odds ratio (OR) 0.20 95% confidence interval (CI) 0.35-0.66, III (OR 0.14 CI 0.3-0.73, p < 0.05); IV (OR 0.05 CI 0.01-0.24, p < 0.01). PCAC was similarly associated with favorable functional outcomes: favorable discharge disposition II (OR 0.12 CI 0.02-0.68), III (OR 0.19 CI 0.05-0.74, p < 0.05) IV (OR 0.05 CI 0.01-0.22, p < 0.01); favorable CPC score II (OR 0.25 CI 0.06-1.03), III (OR 0.14 CI 0.03-0.57, p < 0.01), IV (OR 0.05 CI 0.01-0.20, p < 0.01) and favorable mRS (OR 0.47 CI (0.33-0.68)).

Early (<6 h post-arrest) PCAC severity scoring strongly predicts patient outcomes from cardiac arrest in both OHCA and IHCA.