In the ED we think a lot about pulmonary embolism, and thus decision rules, d-dimers and CTAs. Because we have a low threshold to test for PE, we spend a fair amount of time trying to not get that CTA. There are a number of tools to risk stratify, but we commonly turn to Wells’, which contains a certain amount of clinical gestalt.
Wells’ Criteria is used to risk-stratify into different tiers using seven different criterion (http://www.mdcalc.com/wells-criteria-for-pulmonary-embolism-pe/). Wells’ draws criticism as one of its criterion is fairly subjective: PE is number one diagnosis, or equally likely.
Wether you are early in your career and haven’t formulated your “clinical gestalt” or you just don’t like the subjective nature of it, there is another tool to use….the Revised Geneva Score (http://www.mdcalc.com/geneva-score-revised-for-pulmonary-embolism/). This score uses simple clinical variables including risk factors, symptoms and clinical signs. A score is generated and used to stratify into low, intermediate and high clinical probability.
The probability tiers can be used similarly to Wells’. If the patient falls in the low risk tier, you can consider d-dimer or use PERC to rule out. If the patient is in the intermediate risk obtain d-dimer or if they fall in the high risk tier go straight to CTA.
ACEP Clinical Policy: Critical Issues in the Evaluation and Management of Adult Patients Presenting to the Emergency Department With Suspected Pulmonary Embolism.