Clinical Decision Rules

Emergency medicine as a speciality involves a great deal of uncertainty, probability, and risk. Taking a history and examining a patient provides information which informs our clinical picture. This informs what further investigations we think we will need to provide further information. Through synthesising these discrete pieces of information, we come to what we think is a well-considered diagnosis.

Increasingly, evidence-based tools called clinical decision rules, or CDRs, are used to assist our patient assessment and decision making. These rules are designed to help clinicians make diagnostic or therapeutic decisions. They often involve the synthesis of multiple criteria which are combined to estimate the likelihood of a diagnosis or indicate who may (or may not) require further imaging1.

CDRs are developed in three distinct stages; derivation, validation and implementation2. They serve to offer a standardisation of care using statistical models to guide patient management. Throughout these developmental stages, they are assessed on their accuracy, reliability as well as their impact on patient care3.

• Derivation involves the analysis of patient groups in order to identify factors which may influence outcomes. Such factors are then used as predictors informing the CDR.
• Validation is the process whereby the CDR is assessed prospectively and studied on its accuracy and reliability.
• Implementation study involves adopting the rule in clinical practice and assessing impact on patient care

There are many CDRs available and widely used within Emergency Medicine. We will explore the evidence base around a number of common ED presentations, from minor to severe, to explore how these scores are derived, created, and used. After youve completed this session, weve also included the evidence base behind some other common clinical decision rules.