Diagnosing pulmonary embolism

Diagnosing pulmonary embolus (PE) remains one of the great challenges of emergency medicine. The diagnosis relies on a balance of probabilities rather than any definitive test. The probability is based on history, examination and investigations. The principal investigations are chest X‐ray, arterial blood gas, electrocardiograph, ventilation perfusion scan, ultrasound and angiography where necessary. Newer techniques such as CT scan and magnetic resonance imaging will become more useful as the technology improves. Transoesophoegeal echocardiography is an important investigative tool for massive PE. Thrombolysis is increasingly being used in the management of PE and the higher risk of adverse outcome should be balanced against the probability of false positive results and the use of invasive angiography. 1995 Australasian College for Emergency Medicine and Australasian Society for Emergency Medicine