The effect of chlorhexidine on the incidence of aspiration pneumonia in care home residents: design of a double-blind cluster randomized placebo-controlled trial.

Background:

Pneumonia is an important cause of death in care home residents. Dysphagia and bad oral health are significant risk factors for developing aspiration pneumonia. Oral hygiene care reduces the number of oral bacteria and the risk of aspiration pneumonia, however, it is not yet clear which oral hygiene care intervention is most efficacious in reducing the risk of aspiration pneumonia.
The aim of the study is to assess whether the application of a 0.05% chlorhexidine-containing solution in addition to usual daily oral hygiene care reduces the incidence of pneumonia in physically-disabled care home residents with dysphagia.



Methods/design:

The study is designed as a double-blind cluster randomized placebo-controlled trial, with care home wards as units of randomization. The randomization will be balanced for dysphagia severity and care dependency. During one year, 500 physically-disabled care home residents with dysphagia will be followed. The intervention consists of applying a 0.05% chlorhexidine-containing solution twice daily immediately after the usual oral hygiene care, whereas the control group receives a placebo. The application method of the 0.05% chlorhexidine-containing solution, rinsing the solution or cleaning the oral cavity with a gauze containing 0.05% chlorhexidine-containing solution, is depending on the severity of the dysphagia. Other research data which will be gathered are: age, gender, diseases diagnosed, dysphagia severity, care dependency, medications used actually, number of teeth and implants present, and presence of removable dentures. The study outcome is the incidence of pneumonia diagnosed by a physician, using a set of strictly described criteria. The effect of the intervention on the incidence of pneumonia will be determined using Cox regression analysis.



Discussion:

Using cluster randomization may result in random effect and cluster selection bias. Therefore, randomization will be balanced for dysphagia severity and care dependency. Furthermore, a frailty model will be included in the Cox regression analysis to take into account the clustering of data within care home wards.

The scientific hypothesis of the present study is that oral hygiene care with a 0.05 % chlorhexidine-containing solution, compared to oral hygiene care with a placebo, reduces the incidence of pneumonia in physically-impaired care home residents with dysphagia.

1. Dysphagia Outcome and Severity Scale (DOSS): baseline and endpoint;

2. Care Dependency Scale (CDS): baseline and endpoint;

3. Patient record: Gender, age (baseline)
Diagnoses and medication use (baseline and endpoint);

4. Oral examination:Number of teeth , implants and the presence of removable dentures (baseline);

5. Pneumonia: Pneumonia will be diagnosed by a set of strictly described criteria: When symptoms occur during study.

The intervention consists of the addition of rinsing with a 0.05% chlorhexidine-containing solution twice daily immediately after the usual oral hygiene care. The execution of the intervention is depending on the severity of the dysphagia. The intervention for residents with dysphagia who tolerate thin liquids consists of a 0.05% chlorhexidine-containing oral rinse. The residents have to rinse for 30 seconds twice a day after the usual oral health care.



The intervention for residents with severe dysphagia who cannot tolerate thin liquids consists of additional cleaning the teeth, the gums, the tongue, the palate, and the buccal mucosa with a gauze containing 0.05% chlorhexidine-containing twice daily.



The intervention consists of applying a 0.05% chlorhexidine-containing solution twice daily immediately after the usual oral hygiene care, whereas the control group receives a placebo. The application method of the 0.05% chlorhexidine-containing solution, rinsing the solution or cleaning the oral cavity with a gauze containing 0.05% chlorhexidine-containing solution, is depending on the severity of the dysphagia.