Ancillary Investigations Used in Suspected Pulmonary Embolism (PE)

PE is a relatively common condition that needs to be excluded with confidence due to its significant associated mortality if undiagnosed. Unfortunately, the history is variable, and there are no pathognomonic findings on clinical examination, ABG analysis, ECG or CXR. However, information acquired from this initial clinical assessment, considered in association with historical risk factors for venous thromboembolic disorders can be calculated as a Wells score for PE. This will allow the emergency physician to confidently ascribe the patient to a low, intermediate or high risk category [7].

Without further investigation, however, patients at low risk cannot be confidently reassured and discharged, and those at high risk should not be committed to prolonged anticoagulation. For patients at low risk, the diagnosis can be confidently excluded with a negative D-dimer assay [8]. For patients at intermediate or high risk the diagnosis can be confidently confirmed or excluded with a ventilation perfusion (V/Q) scan or CT pulmonary angiogram (CTPA) [8]. A detailed discussion of the diagnosis and management of PE is presented in session Pulmonary Embolism.