Investigation of Pulmonary Embolism at St. Peter’s Hospital: An Audit Series and Quality Improvement Project Dr Chloe Pettit & Dr Noel Murphy (F1s), Dr Shelley Chapman (SpR), Dr Vineet Prakash & Dr Alexander Chapman (Consultants) Problems Identified Changes Implemented Between Each Audit Conclusions

CT pulmonary angiography (CTPA) is a common Audit 1 Audit 2Audit 3 1. Our interventions have significantly investigation for suspected pulmonary embolism increased the number of complete (PE). We identified two areas for improvement: 1. Re‐education of hospital clinicians regarding 1. Pop‐up box at point of request: requests for CTPA from 6% to 54%. need for Wells score, D‐dimer if indicated and However, further improvements can still 1. Request forms to contain relevant clinical CXR for all CTPA requests, via email campaign be made so that 100% of patients have a information so CTPA is only performed when and Medical Grand Round presentation Wells score and CXR to determine pre‐test indicated. By following current guidelines up to one probability. third of CTPA scans may be avoidable1. 2. Technical changes to CTPA protocol e.g. auto‐ 2. Departmental rejection of incomplete requests trigger, cranio‐caudal scanning direction, 2. Adequate opacification of the pulmonary 2. Adequate contrast opacification of the pulmonary 3. Re‐education of hospital clinicians tree has increased from 52% to 81%, tree to maximise the diagnostic value of CTPA. standardisation of contrast injection rate and 4. Radiographer education regarding formalised volume improving the diagnostic value of our CTPA CTPA protocol and contrast administration studies. Audit Standards Results Recommendations 2 NICE guidelines 2012 : 1. Education for new doctors, A&E doctors 3 •All patients should have a Wells score Key findings: Adequacy of pre‐CTPA criteria and acute medical doctors via a new online •All patients whose Wells score is less than or e‐learning module equal to 4 should have a D‐dimer blood test Similar patient demographics in each audit: •All patients should have had a chest x‐ray (CXR) Average age 67‐69 years 2. Improved screening of requests by •Only those patients who fulfil the criteria below, Male gender 42% ‐ 57% radiographers and radiologists should have a CTPA: 3 main reasons for requests: Shortness of breath, hypoxia, chest pain 3. Departmental posters detailing NICE guidance Origin of requests: 25%‐39% A&E 4. Re‐audit 35%‐37% Acute medical wards Alternative diagnoses reported in 65%‐75% Most commonly consolidation References 17%‐19% Diagnostic yield for PE 1. Atkins SA, Munson S, Jacobson PJ and Kelly TJ. Cost and Risk analysis of CT Pulmonary Angiography to rule out Pulmonary embolism in Low and Very Low Risk CTPA Scans with Emergency Department Patients, RSNA, 2013. •The pulmonary trunk should be opacified with Adequate Opacification 2. NICE, Venous thromboembolic diseases: the 4 management of venous thromboembolic diseases and contrast >250HU according to literature the role of thrombophilia testing, June 2012.

3. Wells PS, Anderson DR, Rodger M, Ginsberg JS, Kearon Method C, Gent M, Turpie AG, Bormanis J, Weitz J, Chamberlain M, Bowie D, Barnes D and Hirsh J. (2000). Derivation of Audit 1 (Sep ‘13): retrospective review of 98 CTPAs a simple clinical model to categorize patients •Changes implemented probability of pulmonary embolism: increasing the models utility with the SimpliRED D‐dimer. Thromb Audit 2 (April ‘14): Re‐audit of 100 CTPAs Haemost 83 (3): 416–20. •Further changes implemented Fig 1: sub‐optimal opacification Fig 2: adequate opacification 4. Jones SE and Wittram C. (2005). The indeterminate CT Audit 3 (August’14): Re‐audit of 100 CTPA studies pulmonary angiogram: imaging characteristics and •Recommendations for the future patient clinical outcome. Radiology; 237 (1): 329‐337.