New approach ruling out pulmonary embolism

Emergency doctors may soon be able to rule out pulmonary embolism earlier without radiation risk thanks to new research from Caboolture Hospital.

Pulmonary embolism (PE) is the third most common presenting acute cardiovascular syndrome and often results in significant harm and death. Clinical decision-making tools exist to guide clinicians in making a definitive diagnosis of PE, however it is equally important to have validated tools to exclude conditions, which in turn helps to optimise resources.

Caboolture Hospital Emergency Department Staff Specialist Dr Karen Furlong received funding from the Emergency Medicine Foundation Jumpstart grant scheme to undertake a retrospective cohort study to determine whether taking a different approach to low-risk patients who present to the emergency department (ED) is a safe strategy to rule out pulmonary embolism.

Clinical decision rules are based on symptoms or observations which allow a patient’s clinical pre-test probability of having a PE to be classified.The pre-test probability will determine if no further testing is required, or alternatively which further tests, such as D-dimer or imaging can be employed to establish a definitive diagnosis.

A D-dimer is a blood test that measures the presence of a protein fragment produced when a blood clot dissolves in the body. High levels of D-dimer protein in the blood can indicate the presence of blood clots, such as deep vein thrombosis or pulmonary embolism. The test is commonly used to help diagnose and monitor the treatment of these conditions.

Applying a higher cut off to low-risk patients has the potential for better patient outcomes and reduced health care costs.

Dr Furlong’s study found that patient benefits for a high-volume presenting population, with a high-stake presenting complaint, included reduced length of stay in ED and a reduction in medical imaging.

“All medical imaging carries risk of harmful radiation exposure,” Dr Furlong said.

“By eliminating potential low-value investigations in low-risk patients, the risk from potentially avoidable radiation exposure is reduced.”

Other studies have shown reduced imaging is not associated with a reduction in diagnostic performance. The flow on effects of reduced imaging is decreased costs to the health system, with this study finding that over the two-year trial period, approximately 323 scans were avoided by using the adjusted D-dimer blood test.

This was Dr Furlong’s first investigator-led project.

“To add to the evidence on reducing unnecessary testing and imaging without compromising patient safety is very pleasing,” Dr Furlong said.

“Generating new knowledge enables us to deliver the best quality health care for our community.”

This formative study provides evidence regarding the efficacy of a higher cut off D-dimer in low-risk groups and lays the foundation for a potential multi-site prospective registry to safely implement the new criteria in the Australian context.

Dr Furlong plans to build on this body of work to inform future value-based evaluations and monitor patient safety.

This research was supported by a grant from the Emergency Medicine Foundation (Australasia) Queensland Research Program.