Ventilator associated pneumonia (VAP) can be a life-threatening infection for those on mechanical ventilation in intensive care units (ICUs). Oral hygiene is one of a number of prevention strategies and there have been a number of previous reviews of this topic.1 The Alhazzani review (see page 89)1 was published just prior to the release of this Cochrane review. This review differs from the Alhazzani in that it is broader, including a wider range of oral hygiene care (OHC) interventions in addition to toothbrushing, with oral swabbing and mouthrinses also included.

This review is typically well-conducted, following established Cochrane methodology. The key finding of this review was that inclusion of chlorhexidine mouthwash or gel as part of the oral health care regime showed a 40% reduction in the odds of developing VAP. This estimate remained very similar when a sensitivity analysis was conducted that excluded the high-risk studies, which found a very similar odds ratio (OR 0.61, 95% CI 0.49 to 0.78, P < 0.001, I2 = 29%). The body of evidence supporting this was assessed as moderate using the GRADE methodology (Table 1)

Table 1 GRADE Working Group* grades of evidence

Toothbrushing versus no toothbrushing did not show a difference in the incidence of VAP (OR 0.69, 95% CI 0.36 to 1.29, P = 0.24). This finding was very similar to Alhazzani who reported a trend towards lower VAP rates (risk ratio, 0.77; 95% confidence interval, 0.50-1.21; P = 0.26).

While the incidence of VAP was reduced, the available evidence did not reveal any positive effects on the other outcomes of mortality, duration of ventilation, length of stay in ICU, duration of antibiotic use. The authors discuss the mortality issue pointing out that a survival analysis by Bekaert et al.4 only found an attributable mortality of 1% at 30 days due to VAP, which is likely to explain the review's result.

In conclusion, effective oral care that includes the use of chlorhexidine should be a routine element of care for mechanically ventilated patents in ICU to reduce the incidence of VAP.