Risk factors for infection by Pseudomonas aeruginosa in patients with ventilator-associated pneumonia

Objective: to investigate the epidemiology of infection by Pseudomonas aeruginosa in patients with ventilator-associated pneumonia (VAP). Design: prospective clinical study. Setting: a medical-surgical ICU in a university hospital. Patients: we followed-up 568 mechanically ventilated patients and 83 episodes of VAP with etiologic diagnosis in 72 patients were retained for analysis. Results: Ps. aeruginosa was isolated in 22 (26.5%) episodes in 18 patients. Of these episodes 7 were directly responsible for death. Using logistic regression analysis, the risk of VAP due to Ps. aeruginosa was increased in patients with chronic obstructive pulmonary disease (relative risk (RR)=29.9, 95% confidence interval (CI)=4.86-184.53), a mechanical ventilation period longer than 8 days (RR=8.1, 95% CI=1.01-65.40) and prior use of antibiotics (RR=5.5, 95% CI=0.88-35.01). Conclusions: patients with VAP and these factors have a greater risk of infection by Ps. aeruginosa and empirical therapy for these episodes should include anti-pseudomonal activity until etiologic diagnosis is established. © 1994 Springer-Verlag.