The patient was classified as having a surgical pathology in the presence of cardiovascular, neurological, general surgery, orthopedic, transplants, or cardiac catheterization procedures. The admission was considered elective when the PICU admission or surgery could be postponed for more than six hours without adverse effects upon the patient. The probability of death for each patient was calculated using the instructions provided by the authors of the PIM2 score.4 The analyzed outcome variables were PICU discharge event (discharge or death)

and length of hospitalization. Descriptive statistics were used to characterize the patients, and the PIM2 performance was assessed by measures of score discrimination and calibration. Discrimination was assessed by calculating the area under Hydroxychloroquine price the receiver operator characteristic (ROC) curve,6 and was considered adequate Alisertib ic50 when the area was > 0.7.7 Calibration was assessed using the Hosmer-Lemeshow goodness-of-fit test,6 and was considered appropriate when the p-value of the test was > 0.05.7 In the Hosmer-Lemeshow test, patients were divided into ten groups with increasing risk probability and a similar number of cases in each group. The comparison between the

mortality rate in the study population with the mortality predicted by PIM2 score was performed by dividing the observed mortality rate by the expected mortality rate (as calculated by the score), termed the standardized mortality rate (SMR).8 The SMR was shown with its 95%

confidence interval (95% CI). If the 95% CI of the SMR included 1, its performance was considered medium; if the 95% CI of the SMR had an upper limit < 1, its performance was considered good; and if the 95% CI of the SMR had a lower limit > 1, its performance was considered poor.9 All analyses were performed using SPSS Statistics for Windows release 12 for Windows (SPSS, Chicago, Illinois, United States). During the study period, PTK6 756 patients were admitted to the PICU, of whom 79 were excluded: 63 patients were younger than 30 days old, ten patients were considered NCCT, four patients died within the first two hours after admission to the unit, and two patients had a suspected diagnosis of brain death on admission, which was later confirmed. A total of 677 patients were included in the study, of whom 568 (83.9%) had a CCC. The main clinical characteristics of the general population and the subgroups of patients with and without CCC are shown in Table 1. The median length of stay, mortality rates, and mean probability of death estimated by PIM2 and SMR of the general population and subgroups are shown in Table 1. When comparing patients with and without CCC, no statistically significant difference was observed in the median length of stay in PICU (3 days vs. 3 days; p = 0.84), in mortality (10.3% vs. 6.4%, p = 0.