Variation in Risk-Adjusted Ventilator-Associated Pneumonia Days Within a Quality Collaborative

Ventilator-associated pneumonia (VAP) is associated with increased mortality, prolonged mechanical ventilation, and longer intensive care unit stays. The rate of VAP (VAPs per 1000 ventilator days) within a hospital is an important quality metric. Despite adoption of preventative strategies, rates of VAP in injured patients remain high in trauma centers. Here, we report variation in risk-adjusted VAP rates within a statewide quality collaborative.

Using Michigan Trauma Quality Improvement Program data from 35 American College of Surgeons-verified Level I and Level II trauma centers between November 1, 2020 and January 31, 2023, a patient-level Poisson model was created to evaluate the risk-adjusted rate of VAP across institutions given the number of ventilator days, adjusting for injury severity, physiologic parameters, and comorbid conditions. Patient-level model results were summed to create center-level estimates. We performed observed-to-expected adjustments to calculate each center's risk-adjusted VAP days and flagged outliers as hospitals whose confidence intervals lay above or below the overall mean.

We identified 538 VAP occurrences among a total of 33,038 ventilator days within the collaborative, with an overall mean of 16.3 VAPs per 1000 ventilator days. We found wide variation in risk-adjusted rates of VAP, ranging from 0 (0-8.9) to 33.0 (14.4-65.1) VAPs per 1000 d. Several hospitals were identified as high or low outliers.

There exists significant variation in the rate of VAP among trauma centers. Investigation of practices and factors influencing the differences between low and high outlier institutions may yield information to reduce variation and improve outcomes.