Chlorhexidine may reduce the risk of ventilator-associated pneumonia in patients treated in intensive care units

CCUCritically ill people, who may be unconscious or sedated while they are treated in ICUs, often need to have machines to help them breathe (ventilators). The use of these machines for more than 48 hours may result in ventilator-associated pneumonia (VAP). VAP is a potentially serious complication in these patients who are already critically ill. Oral hygiene care, using a mouthrinse, gel, toothbrush, or combination, together with breathing-in of secretions, may reduce the risk of VAP in these patients.

What was the research?

A systematic review to examine the effects of oral hygiene care on the incidence of ventilator-associated pneumonia (VAP) in critically ill patients receiving mechanical ventilation in hospital intensive care units (ICUs). We aimed to summarise all the available appropriate research in order to identify evidence-based care for these vulnerable patients.

Who conducted the research?

The research was conducted by a team led by Fang Hua, from Cochrane Oral Health. Huixu Xie, Helen V. Worthington, Susan Furness, Qi Zhang and Chunjie Li  were also on the team.

What evidence was included in the review?

38 randomised controlled trials were selected for inclusion in this review, but only a few (13%) of the studies were well conducted and described.

All of the studies took place in ICUs in hospitals. In total there were 6,016 participants randomly allocated to treatment. Participants were critically ill and required assistance from nursing staff for their oral hygiene care. Most of the studies involved adults only, but the participants were children in three of the studies, and newborns in one study.

We grouped trials into four main comparisons.

1. Chlorhexidine antiseptic mouthrinse or gel compared to placebo (treatment without the active ingredient chlorhexidine) or usual care, (with or without toothbrushing).
2. Toothbrushing compared with no toothbrushing (with or without antiseptics)
3. Powered compared with manual toothbrushing
4. Oral care solutions with other solutions

What did the evidence say?

We found high quality evidence that chlorhexidine, either as a mouthrinse or a gel, reduces the risk of VAP from 25% to about 19%. For every 17 people on ventilators for more than 48 hours in intensive care, the use of oral hygiene care including chlorhexidine will prevent one person developing VAP. However, we found no evidence that oral hygiene care with chlorhexidine makes a difference to the numbers of patients who die in ICU, or to the number of days on mechanical ventilation or days in ICU.

We have only limited evidence on the effects of toothbrushing (with or without antiseptics) and oral care without toothbrushing (with or without antiseptics) on the risk of developing VAP. Three studies showed some weak evidence of a reduction in VAP with povidone iodine antiseptic mouthrinse compared to placebo/saline. Four studies showed some weak evidence of a reduction in VAP with saline rinse compared to saline swab.

There was insufficient evidence to determine whether any of the interventions evaluated in the studies are associated with any unwanted side effects.

How good was the evidence?

The evidence presented was limited by how well the included studies were done and reported. Only 13% of the studies were well conducted and well described. For a number of outcomes, there was not enough information to draw a solid conclusion.

What are the implications for clinicians and the general public?

Effective oral hygiene care is important for ventilated patients in intensive care to reduce ventilator-associated pneumonia. The definition of oral hygiene care varied among the studies included in this review, but common elements include cleaning of the teeth and gums with a swab or gauze, removing secretions using suction, and rinsing the mouth. There is evidence from our review that oral hygiene care incorporating chlorhexidine mouthrinse or gel is effective in reducing the development of ventilator-associated pneumonia in adults in intensive care. We found no evidence of an association between oral hygiene care and mortality, duration of mechanical ventilation, and duration of ICU stay. For the other comparisons assessed in this review, fewer studies contributed evidence and consequently the quality of the body of evidence was lower.

What should researchers look at in the future?

Although the included studies provided some evidence for the benefits of oral hygiene care for critically ill patients to prevent ventilator-associated pneumonia, incomplete reporting of studies is a major limitation. More consistent use of the CONSORT statement for reporting of randomised controlled trials (CONSORT 2012) would increase the value of research.

Further trials of oral hygiene care (including use of manual or powered toothbrushes, or swabs) should report both measures of effectiveness of plaque removal and prevention of ventilator-associated pneumonia. They should also state explicitly whether those patients who have died during the study are included in the calculation of duration outcomes (e.g. duration of ICU stay, duration of mechanical ventilation).

Future studies may also consider adopting the new definitions and diagnostic criteria (ventilator-associated event, VAE) recently developed by the US CDC (Waters 2015), which is likely to overcome the limitations of traditional VAP diagnosis and facilitate high quality synthesis of research findings.


Hua F, Xie H, Worthington HV, Furness S, Zhang Q, Li C. Oral hygiene care for critically ill patients to prevent ventilator-associated pneumonia. Cochrane Database of Systematic Reviews 2013 , Issue 8 . Art. No.: CD008367. DOI: 10.1002/14651858.CD008367.pub2 .

This post is an extended version of the review’s plain language summary, compiled by Anne Littlewood at the Cochrane Oral Health Editorial Base.