Questionable Benefit of Oral Chlorhexidine in Mechanically Ventilated Patients
Clinical question
For patients receiving mechanical ventilation, does routine oral care with chlorhexidine improve outcomes?
Bottom line
Oral care with chlorhexidine decreases the incidence of respiratory tract infections in mechanically ventilated cardiac surgery patients, but not in noncardiac surgery patients. Additionally, the use of chlorhexidine does not have a statistically significant effect on mortality, length of stay (LOS), or duration of mechanical ventilation in either population. Further research is needed to determine the benefit and safety of this common intervention in different patient populations. (LOE = 1a)
Reference
Study design
Meta-analysis (randomized controlled trials)
Funding source
Unknown/not stated
Allocation
Uncertain
Setting
Inpatient (ICU only)
Synopsis
Previous meta-analyses demonstrated the effectiveness of chlorhexidine in the intensive care unit (ICU) for the prevention of ventilator-associated pneumonia, but did not distinguish between cardiac surgery and noncardiac surgery populations. These investigators searched multiple databases including PubMed and Embase, as well as reviewed reference lists of retrieved articles, to find randomized controlled trials that evaluated oral care with chlorhexidine versus oral care with placebo in mechanically ventilated patients for the prevention of nosocomial pneumonia, mortality, LOS, duration of mechanical ventilation, and antibiotic exposure. Two authors independently assessed the studies for inclusion and abstraction of data. The included studies were then rated for quality based on randomization strategy, allocation concealment, blinding, and completeness of follow-up. Of the 16 studies included in the review, 7 took place in combined medical–surgical units, 3 were in cardiac surgery units, and the rest were in other surgical or medical units. The presence of double-blinding in a study correlated with a higher quality rating. Data from the 3 studies of cardiac surgery patients showed fewer respiratory infections in patients receiving chlorhexidine (relative risk [RR] = 0.56; 95% CI, 0.41-0.77), but no association with mortality. The 13 studies involving noncardiac surgery patients, all of which focused specifically on ventilator-associated pneumonia, showed no significant difference in risk, even when the data was limited to the higher quality double-blind studies. However, there was a nonsignificant trend toward higher mortality with chlorhexidine use in this group of trials (RR = 1.13; 0.99-1.29). No significant differences were noted for the duration of mechanical ventilation, ICU LOS, hospital LOS, or antibiotic exposure, though data was limited for the latter 2 outcomes. The authors note that decreased exposure to an endotracheal tube in cardiac surgery patients, as compared with noncardiac surgery patients, may account for the decreased risk of pneumonia seen in this population. The potential increase in mortality in noncardiac surgery patients is harder to explain, but the authors postulate that this may be due to aspiration of chlorhexidine leading to acute lung injury.
Dr. Kulkarni is an assistant professor of hospital medicine at Northwestern University in Chicago.
