Improving Antibiotic Use for Ventilator-Associated Pneumonia Through Diagnostic Stewardship: A Proof-of-Concept Mixed-Methods Study

Abstract

Background Overtreatment of ventilator-associated pneumonia (VAP) in the intensive care unit (ICU) is driven by positive respiratory tract cultures in the absence of a clinical picture of pneumonia. We evaluated the potential for diagnostic stewardship at the respiratory culture reporting step. Methods In this mixed-methods study, we conducted a baseline evaluation of lower respiratory tract (LRT) culture appropriateness and antibiotic prescribing, followed by a non-randomized intervention in two adult ICUs. The intervention was a comment in the report to indicate potential colonization instead of organism identification when LRT cultures were inappropriate, i.e., not meeting criteria for pneumonia as adjudicated by a physician using a standard algorithm. Results At baseline, among 66 inappropriate LRT cultures, antibiotic treatment for VAP was more frequent with identification of potential pathogen(s) in the index culture compared to no growth/normal flora (16/35 (46%) vs 7/31 (23%), P=0.049). In the intervention period, 28 inappropriate cultures with growth of potential pathogen(s) underwent report modification. The proportion of episodes for which antibiotic therapy for VAP was completed was significantly lower in the intervention compared to baseline group (5/28 (18%) vs 16/35 (46%), P = 0.02). Conclusions Diagnostic stewardship for VAP could be facilitated by modification of LRT culture reporting guided by clinical features of pneumonia.