Table 1 Description of the components of the intervention

Leadership endorsement

We obtained approval from the clinical and managerial leads for the ED, radiology, hematology, and thrombosis for a new protocol for the diagnosis of PE.

Ordering D-dimer and CTPA/VQ scan

We moved from the concept of ordering D-dimer or imaging for PE, to the broader concept of “testing for PE.” We created a new order set (Appendix A) which guides ED testing for PE.

The new diagnostic PE pathway starts with D-dimer blood testing in all patients.

We no longer asked the physician to calculate the Wells score to simplify the process and to avoid having physicians artificially increasing the score in order to avoid using D-dimer.

The testing process has been semi-automated. If the D-dimer result is lower than the threshold, the attending physician is notified by the nurse and PE is excluded. If the D-dimer result is higher than the threshold, the patients go directly for a CTPA without the need for physician reassessment. The physician is notified when the imaging report is available.

We made the new PE diagnostic pathway attractive to use by enabling ordering of CTPA without the requirement to first discuss with a radiologist.

Physicians’ education

We met with the ED physicians and nurses with educational material to support the use of the proposed diagnostic workflow.

Personalized confidential physician feedback

We sent each physician a quarterly confidential personalized report containing the following:

The proportion of eligible patients (based on the presenting complain) who had an imaging test, expressed as a percentage: (number of exams requested) × 100/(total number of eligible patients).

The proportion of imaging tests ordered without D-dimer or despite a negative D-dimer, expressed as a percentage: (number of cases in which the algorithm has not been followed in patients receiving imaging) × 100/(total number of imaging test performed).

These metrics were calculated for the individual physician, and compared to the average of all the physicians working in the same ED.

The form was piloted with some of the study clinical investigators (the research manager and two ED physicians with expertise in quality improvement and knowledge translation) and then with a convenience sample of four physicians. The form was modified according to their feedback.

Patients’ information

We developed patient information about the testing process, as well as the risks and benefits of undergoing CT scanning. Moreover, the PE testing order set incorporated nurse facilitated identification of patient-specific goals (for example treatment of pain) so the treating ED physician can focus their treatment and advice on patient-specific needs.