Risk factors for late-onset ventilator-associated pneumonia in trauma patients receiving selective digestive decontamination.

OBJECTIVE: To determine the independent risk factors for late-onset ventilator-associated pneumonia (VAP) in trauma patients receiving selective digestive decontamination (SDD).
DESIGN: A 4-year, prospective cohort study of trauma patients meeting the following criteria: injury severity score >15, and duration of mechanical ventilation >5 days. Predictors of late-onset VAP occurrence were assessed by logistic regression analysis. POPULATION: All patients received SDD consisting of polymixin E, gentamicin, and amphotericin B applied in nostrils, mouth, and gut with a 3-day course of parenteral cefazolin. VAP was suspected on clinical and radiological signs, and confirmed by the presence of at least one microorganism at a concentration of at least 10(4) CFU/ml on the broncho-alveolar lavage. MEASUREMENT: Independent risk factors for late-onset VAP.
RESULTS: A late-onset VAP was diagnosed in 90 (56%) out of 159 patients. Predicting factors for late-onset VAP were: use of non-depolarizing muscle relaxant agents for intubation [3.4 (CI 1.08-10.73)], duration of intubation [1.06 (CI 1.01-1.17)], length of intensive care unit (ICU) stay [1.05 (CI 1.02-1.09)], and prior tracheal colonization [1.03 (CI 1.02-1.21)]. Exposure to prior antimicrobial treatment, except SDD, conferred protection [0.3 (0.12-0.74)].
CONCLUSION: This study confirms the role of duration of intubation, length of ICU stay, and prior tracheal colonization in the development of late-onset VAP. The results also highlight the importance of the initial management on the development of late-onset VAP. The type of neuromuscular blocking agents to intubate trauma patients should be evaluated in future studies.