CRD Summary: This review reported that topical application of chlorhexidine is useful for preventing ventilator-associated pneumonia in mechanically ventilated patients. This was a well-conducted review, but the conclusions should have been slightly more cautious given the clinical and statistical differences between the studies and the unknown quality of some of the included trials.

CRD Commentary: The review question was clear and inclusion criteria were well defined for the intervention, study type and outcomes. The search was well conducted and a funnel plot was used to assess any publication bias. The authors assessed some validity criteria, but could have used this information in their sensitivity analyses. Two reviewers were involved in the review process, which reduces the risk of reviewer bias. Details of the included studies were presented, although it appears that some of the data were not well reported in the original studies. The authors reported heterogeneity between the studies and explored reasons for it. This was a very well-conducted review, but the conclusions should have been slightly more cautious given the clinical and statistical differences between the studies and the unknown quality of some of the included trials.