To compare mortality rate, the adjustment of case-mix variables is needed. The Pediatric Index of Mortality (PIM) 3 score is a widely used case-mix adjustment system of a pediatric intensive care unit (ICU), but there has been no validation study of it in Korea. We aim to validate the PIM3 in a Korean pediatric ICU, and extend the validation of the score from those aged 0–16 to 0–18 years, as patients aged 16–18 years are admitted to pediatric ICU in Korea. A retrospective cohort study of 1,710 patients was conducted in a tertiary pediatric ICU. To validate the score, the discriminatory power was assessed by calculating the area under the receiver-operating characteristic (ROC) curve, and calibration was evaluated by the Hosmer-Lemeshow goodness-of-fit (GOF) test. The observed mortality rate was 8.47%, and the predicted mortality rate was 6.57%. For patients aged < 18 years, the discrimination was acceptable (c-index = 0.76) and the calibration was good, with a χ2 of 9.4 in the GOF test (P = 0.313). The observed mortality rate in the hemato-oncological subgroup was high (18.73%), as compared to the predicted mortality rate (7.13%), and the discrimination was unacceptable (c-index = 0.66). In conclusion, the PIM3 performed well in a Korean pediatric ICU. However, the application of the PIM3 to a hemato-oncological subgroup needs to be cautioned. Further studies on the performance of PIM3 in pediatric patients in adult ICUs and pediatric ICUs of primary and secondary hospitals are needed.

BackgroundIn spite of improved survival after palliation for single ventricle, interstage mortality for a single ventricle with heterotaxy syndrome is unknown. The purpose of this study was to quantify interstage mortality and influence mortality risk factors.MethodsFrom November 1994 until February 2012, all patients that had a functional single ventricle and heterotaxy syndrome who underwent palliative operations at our center were included. Patients with hypoplastic left heart syndrome and operative mortality cases were excluded. The factors that influenced interstage mortality were determined by multivariate Cox analysis.ResultsThere were 16 patients with interstage mortality (41.0%), much higher than the non-heterotaxy group (vs. 11.3%, P = 0.001, OR = 5.478). The major presumptive causes of death were infection or sepsis (37.5%) and unknown sudden death (31.3%). When we compared the survival group and the mortality group with heterotaxy syndrome, Blalock-Taussig shunt as a 1st palliation is most common for both groups but there were more for the mortality group (81.2% vs. 52.2%), and there were more with bidirectional cavo-pulmonary shunt as a 1st palliation in the survival group (10 patients vs. 2 patients). The existence of pulmonary vein stenosis at initial diagnosis was more common for the mortality group. In multivariate Cox analysis, however, the duration of hospitalization at palliation, the duration of intensive care unit stay after palliation and the existence of pulmonary vein stenosis at diagnosis were significant risk factors.ConclusionInterstage mortality for a functional single ventricle with heterotaxy syndrome is significantly higher than for non-heterotaxy syndrome. Therefore more attention should be given to the prevention of interstage mortality in these patients with risk factors.

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