Computed tomography pulmonary angiograms (CTPAs) have become the most widely used technique for diagnosis or exclusion of a pulmonary embolism. Choosing Wisely Australia, in conjunction with The Royal Australian and New Zealand College of Radiologists, recommend "Do not request any diagnostic testing for suspected pulmonary embolism (PE) unless indicated by Wells Score (or Charlotte Rule) followed by PE Rule-out Criteria (in patients not pregnant). Low risk patients in whom diagnostic testing is indicated should have PE excluded by a negative D dimer, not imaging". Our recent literature review identified that CTPAs continue to be overused in emergency departments, and that while clinical practice guidelines, such as the Wells Score or Charlotte Rule, have a strong effect on reducing unnecessary CTPAs, with no significant increased risk of missed diagnosis, the adoption of these tools by emergency department clinicians has remained low.

This study explores the use of CTPAs across all four of Tasmania’s public emergency departments – the Launceston General Hospital, the Mersey Community Hospital, the North West Regional Hospital, and the Royal Hobart Hospital – to identify whether current ordering practices align with evidence-based best practice. These four hospitals cover a wide range of the regional and rural areas across the state, meaning the findings will be relevant and translatable to many health services internationally. A total of 2,957 patient records from across the four emergency departments will be analysed to identify the yield (number of CTPA positive for PE), and whether a recognised clinical practice guideline was used prior to ordering the scan.