Oral decontamination with chlorhexidine reduces the incidence of ventilator-associated pneumonia

Rationale: Ventilator-associated pneumonia (VAP) is the most frequently occurring nosocomial infection associated with increased morbidity and mortality. Although oral decontamination with antibiotics reduces incidences of VAP, it is not recommended because of potential selection of antibiotic-resistant pathogens. We hypothesized that oral decontamination with either chlorhexidine (CHX, 2%) or CHX/colistin (CHX/COL, 2%/2%) would reduce and postpone development of VAP, and oral and endotracheal colonization. Objectives: To determine the effect of oral decontamination with CHX or CHX/COL on VAP incidence and time to development of VAP. Methods: Consecutive patients needing mechanical ventilation for 48 h or more were enrolled in a randomized, double-blind, placebo-controlled trial with three arms: CHX, CHX/COL, and placebo (PLAC). Trial medication was applied every 6 h into the buccal cavity. Oropharyngeal swabs were obtained daily and quantitatively analyzed for gram-positive and gram-negative microorganisms. Endotracheal colonization was monitored twice weekly. Results: Of 385 patients included, 130 received PLAC, 127 CHX and 128 CHX/COL. Baseline characteristics were comparable. The daily risk of VAP was reduced in both treatment groups compared with PLAC: 65% (hazard ratio [HR] = 0.352; 95% confidence interval [CI], 0.160, 0.791; p = 0.012) for CHX and 55% (HR = 0.454; 95% CI, 0.224, 0. 925; p = 0.030) for CHX/COL. CHX/COL provided significant reduction in oropharyngeal colonization with both gram-negative and gram-positive microorganisms, whereas CHX mostly affected gram-positive microorganisms. Endotracheal colonization was reduced for CHX/COL patients and to a lesser extent for CHX patients. No differences in duration of mechanical ventilation, intensive care unit stay, or intensive care unit survival could be demonstrated. Conclusions: Topical oral decontamination with CHX or CHX/COL reduces the incidence of VAP.