Does a force function enhance the use of evidence-based practice when ordering a CTPA? A project to reduce low-value care in the Royal Hobart Hospital Emergency Department

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.

To improve alignment of CTPA ordering with best practice, the Royal Hobart Hospital emergency department implemented a new policy in mid-April 2019. This policy specified that, rather than all CTPA requests requiring approval by the department of medical imaging, a CTPA would be automatically approved if it met the requirements of the Well’s criteria for PE. Implementing this automated process to enhance best practice, potentially reduces the burden on clinicians working in an already busy emergency department.

Data will be collected retrospectively across a 17-month study period (8.5 months both before and after the change), with 519 records from January 2018 to mid-April 2019, and 557 records from mid-April 2019 to December 2019 inclusive. The pre- and post-implementation data will be collected to evaluate the effectiveness of the policy change through identifying the yield (number of CTPA positive for PE), and whether a recognised clinical practice guideline was used prior to ordering the scan.