Criteria for ICU admission and severity of illness scoring

In the UK critical care is a limited resource so must be targeted to those patients who are most likely to benefit. Timely recognition and treatment of the critically ill patient may avoid the need for critical care admission and improve outcome. There is no comprehensive guide to when patients need critical care admission. The support of single-organ failure can generally be managed in high-dependency care, whereas respiratory failure or more than two-organ failure requires ICU admission. Track and trigger systems and critical care outreach teams have been introduced following Department of Health advice to identify sick ward patients and ensure they are treated in a timely fashion to avert deterioration into organ failure. So far there is no conclusive evidence that they achieve these aims. Several severity of illness scores are used in critical care medicine, which have been developed to compare the performance of different units, and as a research and audit tool. Such tools predict outcomes of populations of critically ill patients rather than individuals. Choosing which patient to admit still therefore relies on clinicians’ judgement in addition to assessment of acute physiological derangement and chronic health status.