Risk factors and outcomes associated with ventilator associated pneumonia amongst intubated trauma patients admitted to the general intensive care unit of a major trauma centre

Abstract

Background

Despite the use of care bundles, ventilator associated pneumonia (VAP) remains a frequently occurring health care-associated infection, increasing costs, length of stay (LOS) and mortality. The incidence is higher amongst trauma patients, although due to variable definitions and study populations risk factors for developing VAP are disputed, with few reports from the UK.

Methods

This 6-year review of intubated trauma patients admitted to the general Intensive Care Unit (ICU) of a UK major trauma centre, collected data on suspected risk factors for VAP, as well as demographic information, outcomes and microbiology. Ninety-nine patients who developed VAP within the first 7 days of admission were compared with 191 patient who did not, with multivariable logistic regression used to control for confounding variables.

Results

Univariable analysis suggested that injury severity score (ISS) (34 v 29), head injury (66.7% v 50.8%), polytrauma (79.8% v 68.1%) and ventilator days (10 v 5) were associated with increased risk of VAP, but after adjustment only ventilator days remained significant (OR 1.04, 95% CI 1.01–1.06). Antibiotics within 24 h of admission were associated with reduced odds of developing VAP, whether this was for pulmonary prophylaxis (OR 0.43, 95% CI 0.22–0.83, p = 0.013) or non-pulmonary reasons (OR 0.27, 95% CI 0.15–0.51, p < 0.001).

Conclusions

Only increasing ventilator days was associated with increased odds of developing VAP. The use of early antimicrobials was associated strongly with a reduction in the odds of developing VAP; this could be explained by unmeasured confounding or a prophylactic effect against aspiration.