Antibacterial Effect of Oral Topical Chlorhexidine after Intubation

Abstract & Commentary

Synopsis: In surgical and trauma patients, a single oral application of 2 mL chlorhexidine gluconate was successful in reducing oral bacterial growth over a 72-hour period following intubation.

Source: Grap MJ, et al. Heart & Lung. 2004;33:83-91.

The purpose of this study was to describe the effects of a single early post-intubation oral application of chlorhexidine gluconate (CHG) on oral microbial flora. The study enrolled 34 patients who were admitted to a surgical trauma or neuroscience ICU, who were randomized to receive 2 mL of CHG by spray (n = 11), by swab (n = 12) or no CHG (n = 11). Oral cultures were obtained before administration of CHG, 12 hours after study admission, and every 24 hours for 72 hours or until extubation if this occurred before 72 hours.

No baseline differences were found for demographics, number of gastric residuals > 100 mL (P = 0.99), backrest elevation (P = 0.60) or number of mouth care interventions by nurses during the study (P = 0.95). Ten patients (3 swab, 3 spray, 4 control) had positive cultures during the study, including 5 positive cultures on admission. Two patients (1 swab, 1 spray) had a decrease in culture score (less growth). Culture growth did not decrease in control patients. At 72 hours, 100% of patients in the spray group had cultures with no growth, compared to 67% in the swab group and 50% in the control group. Due to small numbers and early extubation, no conclusions could be drawn in regard to effect of CHG on ventilator-associated pneumonia.

Comment by Leslie A. Hoffman, RN, PhD

In dentistry, chemical antimicrobial agents are used to prevent recolonization by periodontal pathogens following peridontal surgery. The efficacy of CHG, an example of this class of agents, as a bacteriostatic and bactericidal agent in dental plaque control has been recognized since the 1970s. The antiplaque activity of CHG appears to be mainly due to its capacity for strong absorption in multiple sites in the oral cavity, especially tooth surfaces. It has no known adverse effects beyond a tendency to enhance tooth staining and a bad taste. During the first 24 to 48 hours of critical illness, patients are typically unstable and oral care is not a priority. A simple, early intervention, such as that tested in this study, has the potential to decrease bacterial growth until the patient stabilizes and routine oral care can be substituted.

Before the study began, Grap and colleagues tested various doses of CHG (ranging from 1 to 20 mL) and found that 2 mL was adequate to cover all mouth surfaces when delivered as a spray using an atomizer (20 sprays) or by swabbing. Oral cultures were obtained at 3 time points: before administration of CHG, 12 hours later, and every 24 hours up to and including 72 hours after study enrollment. Only 12 subjects had complete data at all time points due to dropout from extubation. From the data obtained, CHG appeared to be effective in reducing bacterial growth as evaluated by trends in the data. Further statistical analysis was not performed due to small group size. The study’s primary limitation is its small sample size and the limited followup interval. Given the simplicity of the intervention and lack of significant adverse effects, use of CHG would seem to be an appropriate strategy for use in this early period following intubation with the goal of preventing ventilator-associated pneumonia.

Leslie A. Hoffman, PhD, RN Department of Acute/Tertiary Care, School of Nursing, University of Pittsburgh, is Associate Editor of Critical Care Alert.