Reducing ventilator associated pneumonia in adult patients through high standards of oral care: a historical control study

Abstract

Objectives: Implement and evaluate the impact of oral hygiene measures (teeth brushing, 1% oral chlorhexidine and oropharyngeal suction) on the incidence of ventilator-associated pneumonia (VAP) and the costs of prevention and treatment.

Design: A historical control study of all 1087 patients, mechanically ventilated for at least 48hours in a general adult critical care unit, between July 2009 and December 2011. The incidence of VAP in 528 patients before a practice change was compared with the incidence in 559 patients after a practice change. The clinical audit cycle was used to review compliance with existing standards and implement a regime of enhanced oral hygiene. The costs of changing the oral care regime and the treatment of VAP with antibiotics was calculated.

Setting: 22 bed combined intensive care and high dependency unit in England.

Main outcome measures: (1) Compliance with standards for oral care. (2) The incidence of VAP before and after the change.

Results: 91% (95% CI 90-93%) compliance with the standards for oral care was achieved throughout the 30 months of the study with very little difference before (90%, 95% CI 88-93%) and after (92%, 95% CI 90-95%) the changes in oral care standards were introduced. Of 528 patients mechanically ventilated for at least 48 hours before the change, 47 developed VAP. The mean incidence of VAP was 0.09 (8.9%) (95% CI 0.07-0.12). The mean VAP per 1000 ventilator days was 13.6 (95% CI 13.1-14.0). After the change 24 of 559 patients developed VAP. The mean incidence of VAP after the change was 0.04 (4.1%) (95% CI 0.03-0.06). The mean VAP per 1000 ventilator days was 6.9 (95% CI 6.5-7.1). There was a £6319 ($10,112, €7518) cost saving on preventing and treating VAP following the practice change. A statistically significant difference (p<0.01) was seen between the incidence of VAP expected and that observed after the change in oral care. This represents a relative risk reduction of 0.53 (95% CI 0.25-0.71) and number needed to treat (NNT) of 21.

Conclusion: An enhanced oral care bundle, incorporating 1% Chlorhexidine Gluconate, was associated with a significant reduction in VAP and the costs of treating VAP. Limitations of the study relate to analysis of other variables, in particular severity of illness, between the two groups and the lack of agreement in the literature on VAP criteria, which limits generalisation of these findings.

Keywords: Chlorhexidine; Clinical audit; Critical care; Nursing; Pneumonia; Prevention; Research; Ventilator associated.