Survival and outcome prediction using the Apache III and the out-of-hospital cardiac arrest (OHCA) score in patients treated in the intensive care unit (ICU) following out-of-hospital, in-hospital or ICU cardiac arrest.

BACKGROUND: There are few data comparing outcome and the utility of severity of illness scoring systems following intensive care after out-of-hospital (OHCA), in-hospital (IHCA) and intensive care unit (ICUCA) cardiac arrest. We investigated survival, factors associated with survival and the correlation and accuracy of general and specific scoring systems, including the Apache III score and the OHCA score in OHCA, IHCA and ICUCA patients.
MATERIAL AND METHODS: Prospective analysis of data on all cardiac arrest patients treated in a tertiary hospital between August 1st 2008 and July 30th 2010. Collected data included resuscitation and post-resuscitation care data as defined by the Utstein Guidelines, Apache III on admission and the OHCA score on admission in OHCA and IHCA patients and after the arrest in ICUCA patients. Statistical methods were used to identify factors associated with outcome and the predictive ability and correlation of the aforementioned scores.
RESULTS: Of a total of 3931 patients treated in the ICU, 51 were admitted following OHCA, 50 following IHCA and 22 suffered an ICUCA and had sustained return of spontaneous circulation (ROSC). Survival at 30 days was highest among ICUCAs (67%) followed by IHCAs (38%) and OHCAs (29%). Using multivariate analysis delay ROSC was the only independent predictor of survival. The OHCA score performed with moderate accuracy for predicting 30-day mortality (area under the curve 0.77 [0.69-0.86] and was slightly better than the Apache III score 0.71 (0.61-0.80). Using multiple logistic regression the Apache III and the OHCA score were both independent predictors of hospital survival and correlation between these two scores was weak (correlation coefficient of 0.244).
CONCLUSIONS: Latency to ROSC seems to be the most important determinant of survival in patients following ICU care after a cardiac arrest in this single center trial. The OHCA score and the Apache III score offer moderate predictive accuracy in ICU cardiac arrest patients but correlated weakly with each other. Illness severity adjustment for cardiac arrest patients in ICU should include features of both these scoring systems.