Effect of Oral Care on Bacterial Colonization and Ventilator-Associated Pneumonia

Critical care nurses are mindful of the need for oral care in patients receiving mechanical ventilation. The Centers for Disease Control and Prevention (CDC) recommend comprehensive oral hygiene programs (potentially including antiseptic agents) for patients at risk for nosocomial pneumonia.1 The Centers for Medicare and Medicaid Services (CMS) have recently identified 10 “never-event” diagnoses with hospital reimbursement implications. CMS has indicated that it will create a code to identify ventilator-associated pneumonia (VAP) as a future preventable hospital-acquired condition.2 Nosocomial pneumonia has been correlated with dental plaque and oropharynx colonization in patients receiving mechanical ventilation.3–10Oropharyngeal flora and microbes undergo changes within 48 hours of admission to the intensive care unit (ICU).11 Endotracheal tubes most likely serve as conduits for colonization because these same microorganisms can be traced to respiratory infections. Subglottal suctioning of secretions lying above the endotracheal cuff has proven effective in reducing rates of VAP.11–14 Although many believe that oral care regimens reduce oropharyngeal colonization, insufficient research exists on the impact of such regimens on VAP. In this review, we summarize the current evidence on the effect that oral care has on dental plaque, oropharyngeal colonization, and nosocomial pneumonia in patients receiving mechanical ventilation.MEDLINE and CINAHL were searched by using the key words oral care, bacterial colonization, VAP, and critically ill patients. Only randomized controlled trials that enrolled mechanically ventilated patients were included.Seven randomized controlled trials from diverse ICUs (n=34-1202) and 1 meta-analysis were retrieved (Table 1). Oral care interventions were mechanical (toothbrushing) or pharmacological (chlorhexidine 0.12%–2%, 2% colistin, or a combination of the 2) delivered via rinse, swab, gel, or paste. Frequency ranged from every 2 hours to 2, 3, or 4 times a day. Measures included dental plaque scales, oral cultures scores, bacterial cultures, clinical pulmonary infection scores, and CDC diagnostic criteria for infections of the lower part of the respiratory tract (eg, fever, leukocytosis, pulmonary infiltrates).Toothbrushing significantly reduced plaque colonization, but 0.12% chlorhexidine swab had no effect in 1 study.19 Chlorhexidine gel (0.2%) reduced positive dental plaque cultures on days 5 to 7 and on day 10 but not for days 11 to 30.8,15 Because 0.2% chlorhexidine had positive effects in 2 studies, more research comparing 0.12% vs 0.2% chlorhexidine and application methods are needed to determine the optimal dose to reduce plaque colonization.Findings for oropharyngeal colonization were mixed but mostly positive. Koeman et al18 found that 2% chlorhexidine/2% colistin was more effective for oropharyngeal colonization because it reduced both gram-positive and gram-negative bacteria (as opposed to 2% chlorhexidine’s gram-positive reduction). In another study, chlorhexidine (spray or swab) trended toward less oropharyngeal growth or no growth.9Results of most studies indicated that chlorhexidine interventions reduced VAP rates.7,15,16,18 Hazard ratios ranged from 35% to 45%, representing the probability that VAP would occur in patients receiving standard oral care versus chlorhexidine interventions.18 DeRiso et al7 reported reduced rates of VAP and gram-negative infection with 0.12% chlorhexidine, with the control group requiring more non-prophylactic intravenous antibiotics. Lower rates of VAP were also found in chlorhexidine-treated patients who were at highest risk.16 In another study, clinical pulmonary infection scores increased less for patients treated with chlorhexidine swab or spray compared with controls, but the differences were not significant.9Evidence for oral care interventions ranges from class I to III (Table 2). Mechanical interventions, specifically toothbrushing, were superior (class I) for reducing dental plaque colonization compared with chlorhexidine (class IIb-III), which had the most effect in the first 5 to 10 days. As a result, patients’ teeth, gums, and tongue should be brushed at least twice a day with soft toothbrushes.21–23Pharmacological interventions had mostly positive effects on oropharyngeal colonization and VAP (class I/III). CDC guidelines1 recommend the use of 0.12% chlorhexidine rinse for cardiac surgery patients during the perioperative period on the basis of the findings of Houston et al.16 Furthermore, the meta-analysis by Pineda et al17 revealed that chlorhexidine interventions were close to significance for beneficial effects on VAP (P = .07). It should be noted that this meta-analysis did not include a recent study by Koeman and colleagues,18 who found that the hazard of acquiring VAP without chlorhexidine interventions ranged from 35% to 45% (P = .01).Numerous surveys have shown that oral care is ranked as a medium24,25 to high care priority26 or is prioritized like other aspects of personal care.27 Toothbrushing was used less often in patients receiving mechanical ventilation.24,26 Interestingly, the strongest evidence for decreasing dental plaque colonization is through mechanical interventions like toothbrushing, but such interventions may be used less frequently in ICUs. Almost all critical care nurses in 1 large survey reported performing routine oral assessments, but only 26% used written tools. Gollins and Yates23 modified the Beck Oral Assessment tool for ICU patients. By rating the condition of the lips, gingiva/mucosa, tongue, teeth, and saliva, a total score is used to determine frequency of oral care, with a minimum standard of at least once every 12 hours (consistent with recommendations of the American Dental Association). Similarly, other nurses have adapted tools for orally intubated patients28 and pediatric ICU patients.29 Before such tools can effectively guide practice, more validity and reliability testing is needed to document how these assessment techniques improve oral health and thus reduce VAP risk.According to current evidence, it appears that toothbrushing has beneficial effects in reducing dental plaque colonization and chlorhexidine may effectively reduce oropharyngeal colonization and VAP. However, more research is needed across multiple populations, especially to determine the frequency of oral care practices that result in the best outcomes for patients.