A critical review: A combined conceptual framework of severity of illness and clinical judgement for analysing diagnostic judgements in critical illness

Aims and objectives: To analyse theoretical literature on severity of illness and clinical judgement and propose a combined conceptual framework for judgements taken to identify patients' clinical states in critical illness and also to critically review and synthesise general severity of illness prognostic models to identify dimensions and attributes of severity of illness in critical illness. Background: The effective treatment of the critically ill requires the early identification of severe illness, and in acute wards, this is predominantly addressed by applying early warning scores focusing on indicators of physiological severity. Clinical judgement complements the application of early warning scores, but is generally not the focus of research and so requires further investigation. Design: A critical review of the literature. Methods: Severity of illness and clinical judgement literature was reviewed to identify themes for a combined conceptual framework for patient assessment in critical illness. MEDLINE and CINAHL (January 1981-December 2011) were searched for general severity of illness prognostic models in critical illness. Eleven research and five systematic review papers meeting review inclusion criteria were selected. Results: Severity of illness is found to be a crucial theoretical construct in critical illness. It can enhance descriptive models of clinical judgement (such as social judgment theory and an inference/correspondence model in diagnostic judgment) when used to analyse and reflect on judgements made to diagnose the clinical state of the patient. Conclusions: A combined conceptual framework of severity of illness and a descriptive clinical judgement model further informs patient assessments about the identification of clinical states in critical illness, alongside early warning scores. Relevance to clinical practice: This article contributes to an understanding of the complexity of patient assessment and diagnostic judgement in critical illness.