Validation of APACHE II score in a surgical intensive care unit

The APACHE II scoring system was applied to 301 surgical intensive care admissions over a 9-month period. The mean age of patients admitted was 52.39 years (SD 19.3) and the mean duration of stay was 5.37 days (SD 8.93). The overall mortality was 17.27%. The mean APACHE II scores for survivors was 12.94 (SD 7.43) and non-survivors 28.19 (SD 10.43). There was good correlation between expected mortality predicted by the APACHE II system and observed mortality (r = 0.9732). Using a predicted risk criterion of 0.5 to distinguish between those predicted to survive and die, of the 45 patients predicted to die, only 30 actually did so. No patient survived with an APACHE II score of more than 40 and with a predicted risk of death greater than 0.87. We found the APACHE II system useful for evaluating ICU performance and risk stratification for the purpose of therapeutic trials but not as a triage tool.