Data sourcesElectronic databases searched were Cochrane Oral Health's Trials Register, the Cochrane Central Register of Controlled Trials (CENTRAL), Medline Ovid, Embassy Ovid, LILACS BIREME Virtual Health Library, CINAHL EBSCO, Chinese Biomedical Literature Database, China National Knowledge Infrastructure, Wan Fang Database and VIP Database ClinicalTrials.gov and the World Health Organisation International Clinical Trials Registry Platform for ongoing trials. No restrictions on language or date of publication.Study selectionRandomised controlled trials (RCTs) were included evaluating OHC in the form of mouthwashes, swabs or toothbrushing or in combination in critically ill patients receiving mechanical ventilation.Data extraction and synthesisTwo reviewers carried out data extraction independently. Study authors were contacted for additional information. Random-effects meta-analyses were performed where data could be pooled.ResultsThirty-eight RCTs (6,016 participants) were included. Five trials (13%) were assessed at low risk of bias, 26 studies (68%) high and seven studies (18%) of unclear risk of bias. There were four main comparisons; chlorhexidine (CHX mouthrinse or gel) versus placebo/usual care, toothbrushing versus no toothbrushing, powered versus manual toothbrushing and comparisons of oral care solutions.Evidence from 18 RCTs (2451 participants, 86% adults) shows that CHX mouthrinse or gel, as part of OHC, reduces the risk of VAP compared to placebo or usual care from 25% to about 19% (RR 0.74, 95% confidence intervals (CI) 0.61 to 0.89, P = 0.002, heterogeneity I2 = 31%). Number needed to treat (NNT) = 17 (95% CI 10 to 33).There is no evidence of a difference between CHX and placebo/usual care for the outcomes of mortality (RR 1.09, 95% CI 0.96 to 1.23, P = 0.18, I2 = 0%, 15 RCTs, 2163 participants, moderate quality evidence), duration of mechanical ventilation (MD -0.09 days, 95% CI -1.73 to 1.55 days, P = 0.91, I2 = 36%, five RCTs, 800 participants, low quality evidence) or duration of intensive care unit (ICU) stay (MD 0.21 days, 95% CI -1.48 to 1.89 days, P = 0.81, I2 = 9%, six RCTs, 833 participants, moderate quality evidence). There is insufficient evidence to determine the effect of CHX on duration of systemic antibiotics, oral health indices, caregivers' preferences or cost. Only two studies reported any adverse effects, and these were mild with similar frequency in CHX and control groups.The effect of toothbrushing (± antiseptics) is uncertain on the outcomes of VAP (RR 0.69, 95% CI 0.44 to 1.09, P = 0.11, I2 = 64%, five RCTs, 889 participants, very low quality evidence) and mortality (RR 0.87, 95% CI 0.70 to 1.09, P = 0.24, I2 = 0%, five RCTs, 889 participants, low quality evidence) compared to OHC without toothbrushing (± antiseptics).There is insufficient evidence to determine whether toothbrushing affects duration of mechanical ventilation, duration of ICU stay, use of systemic antibiotics, oral health indices, adverse effects, caregivers' preferences or cost.Only one trial (78 participants) compared use of a powered toothbrush with a manual toothbrush, providing insufficient evidence to determine the effect on any of the outcomes of this review.Fifteen trials compared various other oral care solutions. There is very weak evidence that povidone iodine mouthrinse is more effective than saline/placebo (RR 0.69, 95% CI 0.50 to 0.95, P = 0.02, I2 = 74%, three studies, 356 participants, high risk of bias) and that saline rinse is more effective than saline swab (RR 0.47, 95% CI 0.37 to 0.62, P <0.001, I2 = 84%, four studies, 488 participants, high risk of bias) in reducing VAP. Due to variation in comparisons and outcomes among trials, there is insufficient evidence concerning the effects of other oral care solutions.ConclusionsThe results from high quality evidence found that oral hygiene care (OHC), including chlorhexidine mouthwash or gel, reduces the risk of developing ventilator-associated pneumonia in critically ill patients from 25% to about 19%. However, there is no evidence of a difference in the outcomes of mortality, duration of mechanical ventilation or duration of ICU stay.There is no evidence that OHC including both antiseptics and toothbrushing is different from OHC with antiseptics alone, and some weak evidence to suggest that povidone iodine mouthrinse is more effective than saline/placebo, and saline rinse is more effective than saline swab in reducing VAP. There is insufficient evidence to determine whether powered toothbrushing or other oral care solutions are effective in reducing VAP. There is also insufficient evidence to determine whether any of the interventions evaluated in the studies are associated with adverse effects.
