Oral Cleansing with Chlorhexidine to Decrease the Incidence of Nosocomial Pneumonia: Using the Right Concentration in the Right Place

Abstract

To the Editor—We read with interest the recent study Bellissimo-Rodrigues et al 1 on the use of 0.12% chlorhexidine for prevention of nosocomial pneumonia. The authors concluded that 0.12% chlorhexidine was not effective in decreasing the incidence of nosocomial respiratory infection. However, chlorhexidine prolonged the infection-free survival time in this study. We have a few observations. In the present study, 0.12% chlorhexidine prolonged the onset of lower respiratory tract infections (11.3 days, compared with 7.6 days for placebo). However, the organisms isolated from these patients were not reported. Chlorhexidine is a broad-spectrum antiseptic with significant activity against gram-positive bacteria. 2 Therefore, it is necessary to investigate whether this delay in the onset of first respiratory infection was also accompanied by a difference in the microbial etiologies. In a larger, single-center study, we recently found that oropharyngeal cleansing with 0.2% chlorhexidine did not decrease the incidence of nosocomial pneumonia among intensive care unit (ICU) patients, although length of ICU stay was reduced in intubated patients and those receiving mechanical ventilation. 3 Similarly, other studies using chlorhexidine in a concentration of 0.2% or less in ICU patients reported improvement in surrogate outcomes but not in the incidence of pneumonia or mortality. 4-6 In contrast, the 2 studies of 2% chlorhexidine for oropharyngeal cleansing both showed reduction in the incidence of pneumonia. 7,8 Therefore, we suggest that future studies of oral cleansing with chlorhexidine among ICU patients should use higher concentrations (2%).