Effectiveness and acceptability of a computerized decision support system using modified Wells criteria for evaluation of suspected pulmonary embolism.

STUDY OBJECTIVE Ready availability of computed tomography (CT) angiography for evaluation of pulmonary embolism in emergency departments (EDs) is associated with a dramatic increase in the number of CT angiography tests. The aims of this study are to determine whether a validated prediction algorithm embedded in a computerized decision support system improves the positive yield rate of CT angiography for pulmonary embolism and is acceptable to emergency physicians. METHODS This study was conducted as a prospective interventional study with a retrospective preinterventional comparison group. RESULTS The implementation of the computerized physician order entry-based computerized decision support system was associated with an overall increase in the positivity rate of from 8.3% (95% confidence interval [CI] 4.9% to 12.9%) preintervention to 12.7% (95% CI 8.6% to 17.7%) postintervention, with a difference of 4.4% (95% CI -1.4% to 10.1%). A total of 404 patients were eligible for inclusion. Physician nonadherence to the computerized decision support system occurred in 105 (26.7%) cases. Fifteen patients underwent CT angiography despite low Wells score and negative D-dimer result, all of whose results were negative for pulmonary embolism. Emergency physicians did not order CT angiography for 44 patients despite high pretest probability, with one receiving a diagnosis of pulmonary embolism on a subsequent visit and another, of DVT. When emergency physicians adhered to the computerized decision support system for the evaluation of suspected pulmonary embolism, a higher yield of CT angiography for pulmonary embolism occurred, with 28 positive results of 168 CT angiography tests (16.7%; 95% CI 11.4% to 23.2%) and a difference compared with preintervention of 8.4% (95% CI 1.7% to 15.4%). Physicians cited the time required to apply the computerized decision support system and a preference for intuitive judgment as reasons for not adhering to the computerized decision support system. CONCLUSION Use of an evidence-based computerized physician order entry-based computerized decision support system for the evaluation of suspected pulmonary embolism was associated with a higher yield of CT angiography for pulmonary embolism. The computerized decision support system, however, was poorly accepted by emergency physicians (partly because of increased computer time), leading to possibly selective use, reducing the effect on overall yield, and leading to removal of the computerized decision support system from the computer order entry. These findings emphasize the importance of facilitation of rule-based decisionmaking in the ED and attentiveness to the complex demands placed on emergency physicians.