Can we prevent ventilator associated pneumonia?

Ventilator associated pneumonia has been characterized by some policy experts as a “never event.” But despite the popularity of “VAP bundles” their effectiveness in preventing ventilator associated pneumonia is not clear. New data from a study in Clinical Infectious Diseases may shed some light. The study looked at the ling-term effect of a bundle of eight interventions:

Results. Baseline and intervention VAP rates were 22.6 and 13.1 total VAP episodes over total mechanical ventilation duration per 1000 ventilation-days, respectively, and 26.1 and 14.9 first VAP episodes over mechanical ventilation duration at VAP or hospital discharge per 1000 procedure-days, respectively (P less than .001). VAP rates decreased by 43% in both statistical analyses and remained significant after adjustment for confounders (Cox adjusted hazard ratio, 0.58; 95% confidence interval, 0.46–0.72; P less than .001). Daily VAP hazard rates on ventilation days 5, 10, and 15 were 2.6%, 3.5%, and 3.4%, respectively, during the baseline period and 1.4%, 2.3%, and 2%, respectively, during the intervention period.

Conclusion. Our preventive program produced sustained VAP rate decreases in the long term. However, VAP rates remained substantial despite high compliance with preventive measures, suggesting that eliminating VAP in the intensive care unit may be an unrealistic goal.

An earlier paper describing the pilot study listed the interventions:

1) comply with hand-hygiene; 2) comply with correct glove-and-gown use; 3) maintain adequate endotracheal cuff pressure; 4) ensure bed backrest elevation less than30° (in the absence of medical contraindication); 5) avoid ventilator-circuit disconnection and perform tracheal aspiration only when necessary; 6) provide good oral hygiene; 7) use an orogastric rather than a nasogastric tube; and 8) avoid gastric overdistension.

What are the lessons from this and previous studies on VAP? First, although VAP can be reduced, a substantial incidence remains despite aggressive measures. Based on the evidence we have so far there is no warrant for classifying VAP as a medical error or a never event. Second, there are multiple combinations of interventions which could be bundled. Since evidence for individual interventions is limited, the optimal bundle is not known.