The clinical utility of invasive diagnostic techniques in the setting of ventilator-associated pneumonia

Objective: To evaluate the clinical utility of bronchoscopy with protected brush catheter (PBC) and BAL for patients with ventilator-associated pneumonia (VAP), Design: Prospective cohort study, Setting: Ten tertiary care ICUs in Canada. Patients: Ninety-two mechanically ventilated patients with a clinical suspicion of VAP who underwent bronchoscopy were compared with 49 patients with a clinical suspicion of pneumonia who did not. Interventions: None. Measurements and results: We compared antibiotic use, duration of mechanical ventilation, ICU stay, and mortality. In addition, for patients who received bronchoscopy, we administered a questionnaire (before and after bronchoscopy) to evaluate the effect of PBC or BAL on (1) physician perception of the probability of VAP, (2) physician confidence in the diagnosis of VAP, and (3) changes to antibiotic management. After bronchoscopy results became available, from the physician's perspective, the diagnosis of VAP was deemed much less likely (p < 0.001), confidence in the diagnosis increased (p = 0.03), and level of comfort with the management plan increased (p = 0.02). Following the results of invasive diagnostic tests, in the group that underwent bronchoscopy, patients were receiving fewer antibiotics (31/92 vs 9/49, p = 0.05) and more patients had treatment with all their antibiotics discontinued (18/92 vs 3/49, p = 0.04) compared with the group that did not undergo bronchoscopy. Duration of mechanical ventilation and ICU stay were similar between the two groups, but mortality was lower in the group that underwent bronchoscopy with PEG or BAI, (18.5% vs 34.7%, p = 0.03). Conclusions: Invasive diagnostic testing may increase physician confidence in the diagnosis and management of VAP and allows for greater ability to limit or discontinue antibiotic treatment. Whether performing PBC or BAL, affects clinically important outcomes requires further study.