Evaluation of intensive care unit performance in Lithuania using the SAPS II system

Background and objective: Outcome prediction and evaluation of intensive care unit (ICU) performance using severity of illness scoring is a tool for the estimation of effectiveness and quality of intensive care. We used the simplified acute physiology score (SAPS) II system to evaluate ICU performance. Methods: The present study is a prospective observational study in an ICU at Vilnius University Emergency Hospital, Lithuania. The observed death rate was compared with the predicted death rate calculated using SAPS II system. The ability of the SAPS II prognostic system to predict the probability of hospital mortality was assessed with discrimination and calibration measures. Results: Two-thousand-and-sixty-seven patients consecutively admitted to the ICU were studied. The median SAPS II score on the first ICU day was 29. The SAPS II system showed a good ability to separate those patients predicted to live from those predicted to die (an area under the receiver operating characteristic curve was 0.883). The calibration curve demonstrated under-prediction of the actual death rate (Hosmer-Lemeshow goodness-of-fit test, Χ 2 = 56.98; df = 8; P < 0.001). The observed mortality was higher than predicted by the SAPS II equation (observed to predicted ratio is 1.28). Conclusions: The SAPS II system is a useful tool for the assessment of ICU performance. This system demonstrated a good ability of discrimination, but an under-prediction of the actual mortality rate, in Lithuanian ICUs.