Pulmonary embolism (PE) refers to blood clots in the lung. They can cause sudden death, collapse, chest pain, shortness of breath yet sometimes they cause no symptoms at all and are discovered incidentally. As they can be severe, they have become regarded as a not-to-miss diagnosis. As they can present with a variety of symptoms, emergency clinicians consider the possibility of PE on a frequent basis.
When considering whether a patient has a PE, the clinician may confirm or exclude the diagnosis directly with definitive chest scans. However, these scans are time consuming, costly and have other side effects including exposure to radiation and to chemical contrast agents. When patients are assessed to be less likely of having a PE, it is often possible to safely exclude PE by applying a set of clinical decision rules or doing a blood test called a D-dimer. If the level of D-dimer is below a certain threshold, then PE can be excluded.
We aim to safely exclude PE without scans where possible. Evidence has been building that employing a higher D-dimer threshold is reasonable, yet uptake of this newer approach is limited. We hope to demonstrate that a higher threshold can work in Australia without compromising safety. This will be a large study that answers this question and if shown to be the case, then patient care can be improved while using less resources in busy emergency departments.