Tabbutt S, et al. - Researchers performed an observational analysis of 8,543 admissions from 23 dedicated cardiac ICUs to develop a postoperative mortality case-mix adjustment model to facilitate assessment of cardiac ICU quality of care, and to describe variation in adjusted cardiac ICU mortality across hospitals within the Pediatric Cardiac Critical Care Consortium. The novel case-mix adjustment model finally included age, chromosomal abnormality/syndrome, previous cardiac surgeries, preoperative mechanical ventilation, and surgical complexity. Open sternum, mechanical ventilation, maximum vasoactive inotropic score, and extracorporeal membrane oxygenation were the significant early postoperative risk factors. The model exhibited excellent discrimination (C statistic, 0.92) and sufficient calibration. Five-fold difference in standardized mortality ratio were voted when comparison across Pediatric Cardiac Critical Care Consortium hospitals was done. Two hospitals displayed markedly better-than-expected and two displayed markedly worse-than-expected mortality. This study for the first time demonstrated the existence of variation in mortality as a quality metric across dedicated cardiac ICUs. These findings may assist in reducing mortality after cardiac surgery.