Severity of Illness Scoring Systems in Critical Care

Abstract

Critical care consumes about 4% of national health expenditure and 0.65% of United States gross domestic product. There are approximately 94,000 critical care beds in the United States, and provision of critical care services costs approximately $80 billion per year. The enormous costs and the heterogeneity of critical care have led to scrutiny of patient outcomes and cost-effectiveness by a variety of governmental and nongovernmental organizations; furthermore, individual critical care practitioners and their hospitals should evaluate the care delivered. This review discusses scoring systems in medicine, critical care systems, development, validation, performance, and customization of the models, adult intensive care unit (ICU) prognostic models, model use, limitations, prognostic models in trauma care, perioperative scoring systems, assessment of organ failure, severity of illness and organ dysfunction scoring in children, and future directions. Figures show the distribution of predicted risk of death using two different prediction models among a population of patients who ultimately are observed to either live or die, a comparison of “expected” deaths (based on the expectation that the predicted probability from the model is correct) to observed deaths within each of the 10 deciles of predicted risk, the importance of disease in the risk of death equation, and the revised Rapaport-Teres graph for ICUs in the Project IMPACT validation set. Tables list three main ICU prognostic models, study characteristics and performance of the fourth-generation prognostic models, variables included in the fourth-generation prognostic models, potential uses of adult ICU prognostic models, variables included in the calculation of the organ failure scores, and sequential organ failure assessment. This review contains 4 highly rendered figures, 6 tables, and 293 references