Monaz: Hello, I'm Monaz Mehta, editor in the Cochrane Editorial and Methods department. There are many Cochrane reviews about the management of patients in intensive care units, covering a wide range of interventions, and the second update of one of these, in December 2020, brought together the latest evidence on the effects of oral hygiene care. Here's the lead author, Fang Hua from Wuhan University in China to tell us about the latest findings.

Fang: Many critically ill patients who are treated in an intensive care unit, or ICU, will need mechanical ventilation to help them to breathe. However, one of the complications that they may develop is ventilator-associated pneumonia, which has been found to affect more than one in every three patients in some studies. We also know that a patient's oral health deteriorates following admission to ICU. Dental plaque may accumulate more quickly because of the increased likelihood of dry mouth, and the presence of the ventilation tube makes oral care more difficult. These critically ill patients are dependent on hospital staff to meet their needs for nutrition and hygiene, including oral hygiene, and it's important to know how best to deliver this.
With that in mind, our review evaluates oral hygiene care interventions used in patients on ventilators in intensive care units to determine the effects on the development of ventilator-associated pneumonia. Our secondary outcomes included mortality and adverse events of the interventions.
We included 40 trials, with more than 5700 patients in this latest update. The two main comparisons were oral hygiene using a chlorhexidine mouthwash or gel compared to placebo or usual care, and oral hygiene with toothbrushing compared to oral hygiene without it.
There was moderate-certainty evidence, based on 13 trials, that chlorhexidine rinse or gel reduced the risk of ventilator-associated pneumonia from about 26% to 18%. There was no evidence of a difference in the proportion of deaths between the groups and, in the two trials that were the only ones to present information on adverse effects, these were reported to be mild with similar numbers in both groups.
In our second main comparison, we found that toothbrushing (with or without antiseptics) may reduce the incidence of ventilator-associated pneumonia, based on low-certainty evidence from five trials, with no evidence of a difference in death with and without toothbrushing.
In summary, oral hygiene care including chlorhexidine mouthwash or gel and tooth brushing makes it less likely that a critically ill patient will develop ventilator-associated pneumonia. But we found no evidence of a difference in mortality and insufficient evidence to determine whether any of the interventions evaluated in the studies are associated with adverse effects.

Monaz: If you would like to read more about the evidence for chlorhexidine and tooth brushing, and the several other types of oral hygiene care included in the review, you can find its full version online at Cochrane Library dot com. Just go to the website and search 'oral hygiene care in ICU' to get the link to it.