282 Implementation of a Pulmonary Embolism Diagnostic Protocol Reduces Imaging

Abstract

Knowledge translation (KT) in health care is defined by the synthesis, dissemination, and application of knowledge to improve health, provide more effective health services and products, and strengthen the health care system. Pulmonary artery computerized tomography (PACT) is considered the test of choice for diagnosis of pulmonary embolism (PE); however, it has well-known potential complications and implications for cost, throughput, patient satisfaction, and resource allocation. The Wells Criteria and pulmonary embolism rule-out criteria (PERC) are validated tools to rule out PE and can safely avoid PACT in patients; nonetheless they are not universally applied. In October 2012 ACEP sponsored a seminar on KT and the rational use of clinical rules in ruling out PE in the ED. Subsequently, to reduce the number of unnecessary PACTs in our department, and in keeping with the principles of KT, we implemented a rational, evidence-based protocol to reduce the number of PACTs performed in our emergency department (ED). We undertook to study the effectiveness of this protocol. This is a prospective observational before and after study. We compared the number of PACTs ordered in 2011 as a control to the number ordered in the 6 months after instituting a KT program followed by a departmentally mandated protocol for the ordering of PACT for all patients with suspected PE. The setting is an urban teaching tertiary care hospital with an ED census of 100,000. The patient population is those suspected of having PE. The protocol calls for a Wells score to be calculated for all patients. Low risk patients then have their PERC score calculated. No further testing is performed on PERC negative patients. Those who fail PERC criteria have d-dimer testing. Intermediate risk patients have immediate d-dimer testing, and high risk patients have a PACT ordered. Those patients who have negative d-dimer results have no further testing. An automatic report for all PACT for PE was generated. All providers who order a PACT outside the protocol are asked to explain why they thought the PACT necessary despite the negative evaluation. Primary endpoint was number of PACT ordered for which a sample size to detect a 20% reduction was determined to be 174 patients. During the six-month study period, 361 PACT were reported ordered. This represents 7.39 scans per 1000 patient visits versus 11.27 in the control period or a reduction of 34% (P<.0001). However, of PACTs ordered, only 263 PACTs were performed, the difference due to cancelled orders, miscounted scans done for other diagnoses, etc. This represents 5.38 scans per 1000 visits or a reduction of 52% (P<.0001). Mean age was 60.9 (SD 19.8) and 57.8% were women. The overall prevalence of PE was 13.4%. There were a total of 70 protocol violations during the protocol period. The PE prevalence when the protocol was followed was 14.5% versus 5.7% when it was not (P=.0368). The proportion of positive PE CTAs was significantly higher during the study period compared to a historical control from 2011 (13.4% versus 7.3%, P<.0001). The goal of this KT project was to reduce the number of PACTs performed in our ED by reinforcing the best evidence-based approach, and as departmental policy. We found the use of our protocol resulted in a significant reduction in PACTs. Our results show that KT can benefit patients with suspected PE in the ED by reducing unnecessary PACT.