Effect from Multiple Episodes of Inadequate Empiric Antibiotic Therapy for Ventilator-associated Pneumonia on Morbidity and Mortality Among Critically Ill Trauma Patients

Background: Empiric antibiotic therapy is routinely initiated for patients with presumed ventilator-associated pneumonia (VAP). The impact of inadequate empiric antibiotic therapy (IEAT) may vary among critically ill populations. The purpose of this retrospective study was to determine the effect of IEAT on the outcome for adult trauma patients with VAP.

Methods: This study enrolled 82 patients with multiple VAP episodes (200 VAP episodes; mean, 2.4 +/- 0.65 per patient; range, 2-5 episodes). An episode of IEAT was a VAP episode with empiric therapy having no in vitro activity against causative bacteria. Overall, there were 78 (39%) IEAT episodes involving 54 patients. Most often, IEAT was attributable to the presence of Acinetobacter spp, Stenotrophomonas maltophilia, or Alcaligenes xylosoxidans. All the patients received appropriate definitive therapy according to the final culture. The patients were classified by number of IEAT episodes: 0 (n = 28), 1 (n = 34), and more than 1 (n = 20).

Results: Demographics and injury severity were similar among the groups. The mortality rate was 3.6% for no episodes, 8.8% for one episode, and 45% for more than one episode (p < 0.001). On the basis of multiple logistic regression, experiencing multiple IEAT episodes was independently associated with the risk of death (odds ratio, 4.28; 95% confidence interval, 1.44-12.71). Additionally, experiencing multiple IEAT episodes was associated with prolonged intensive care unit stay (p = 0.007) and prolonged mechanical ventilation (p = 0.005).

Conclusions: Critically ill trauma patients experiencing multiple episodes of IEAT for VAP have increased morbidity and mortality. These findings reinforce the importance of developing and refining a unit-specific pathway for the empiric management of VAP.