Objective: To assess the accuracy of provider estimates of ventilator-associated pneumonia (VAP) diagnostic probability in various clinical scenarios.
Design: We conducted a clinical vignette-based survey of intensive care unit (ICU) physicians to evaluate provider estimates of VAP diagnostic probability before and after isolated cardinal VAP clinical changes and VAP diagnostic test results. Responses were used to calculate imputed diagnostic likelihood ratios (LRs), which were compared to evidence-based LRs.
Setting: Michigan Medicine University Hospital, a tertiary-care center.
Participants: This study included 133 ICU clinical faculty and house staff.
Results: Provider estimates of VAP diagnostic probability were consistently higher than evidence-based diagnostic probabilities. Similarly, imputed LRs from provider-estimated diagnostic probabilities were consistently higher than evidence-based LRs. These differences were most notable for positive bronchoalveolar lavage culture (provider-estimated LR 5.7 vs evidence-based LR 1.4; P < .01), chest radiograph with air bronchogram (provider-estimated LR 6.0 vs evidence-based LR 3.6; P < .01), and isolated purulent endotracheal secretions (provider-estimated LR 1.6 vs evidence-based LR 0.8; P < .01). Attending physicians and infectious disease physicians were more accurate in their LR estimates than trainees (P = .04) and non-ID physicians (P = .03).
Conclusions: Physicians routinely overestimated the diagnostic probability of VAP as well as the positive LRs of isolated cardinal VAP clinical changes and VAP diagnostic test results. Diagnostic stewardship initiatives, including educational outreach and clinical decision support systems, may be useful adjuncts in minimizing VAP overdiagnosis and ICU antibiotic overuse.