Clinical Decision Support Increases PE Diagnoses

Emergency department physicians detect more acute pulmonary embolisms (PE) when they use evidence-based clinical decision support (CDS) than when they override the alerts, according to a study published in Radiology.

Researchers from Brigham and Women’s Hospital, Harvard Medical School, and Massachusetts General Hospital in Boston, MA, sought to determine the frequency of, and yield after, provider overrides of evidence-based CDS for ordering CT pulmonary angiography in the emergency department.

The researchers looked at all patients suspected of having PE and who underwent CT pulmonary angiography between January 1, 2011, and August 31, 2013, at a tertiary care, academic medical center ED. Each CT order for pulmonary angiography was exposed to CDS on the basis of the Wells criteria. According to the modified Wells criteria for PE, scores more than 4 indicate a likely PE; scores of 4 or less indicated that PE is unlikely. If patients had a Wells score of 4 or less, the CDS alerts suggested d-dimer testing.

The yield of CT pulmonary angiography (number of positive PE diagnoses/total number of CT pulmonary angiographic examinations) was compared in patients in whom providers overrode CDS alerts, by performing CT pulmonary angiography in patients with a Wells score 4 or less, and a normal d-dimer level or no d-dimer testing) (override group) and those in whom providers followed Wells criteria (CT pulmonary angiography only in patients with Wells score more than 4 or 4 or less with elevated d-dimer level) (adherent group).

The researchers found 2,993 CT pulmonary angiography studies were performed on 2,655 patients. Of these, 563 examinations had a Wells score of 4 or less but did not undergo d-dimer testing and 26 had a Wells score of 4 or less and had normal d-dimer levels. The results showed that the yield of CT pulmonary angiography was 4.2% in the override group (25 of 589 studies, none with a normal d-dimer level) and 11.2% in the adherent group (270 of 2404 studies). The researchers calculated that the odds of an acute PE finding were 51.3% lower when providers overrode alerts than when they followed CDS guidelines. Comparison of the two groups including only patients unlikely to have PE led to similar results.

Most overrides were due to the lack of d-dimer testing in patients who were unlikely to have a PE, the researchers noted. “The odds of an acute PE finding in the ED when providers adhered to evidence presented in CDS were nearly double those seen when providers overrode CDS alerts,” they concluded.