Impact of adequacy of initial antimicrobial therapy on the prognosis of patients with ventilator-associated pneumonia.

Objective: To study the prognostic impact of the appropriateness of initial antimicrobial therapy in patients suffering from ventilator-associated pneumonia (VAP).

Design And Setting: Observational cohort from January 1994 to December 2001 in one intensive care unit (ICU) from an university-affiliated, urban teaching hospital.

Patients: All 132 consecutive patients exhibiting bacteriologically documented VAP during ICU stay.

Measurements And Results: Initial antimicrobial treatment was deemed appropriate when the period from initial VAP diagnosis and subsequent administration of antibiotics was within 24 h and all causative pathogens were in vitro susceptible to at least one of the antibiotics of the regimen. Such a treatment was present in 106 episodes. Fifty-eight patients died. In bivariate analysis an appropriate initial antimicrobial therapy was associated with a significantly lower mortality rate (40% vs. 62%). In multivariate analysis the three independent factors present upon VAP onset and associated with death were pulmonary involvement of more than a single lobe on chest radiograph, platelet count less than 150000/mm(3), and Simplified Acute Physiology Score II higher than 37. Appropriate antimicrobial therapy was associated with a nonsignificant trend toward a lower mortality.

Conclusions: In our cohort the mortality rate was lower in patients suffering from VAP when the initial antimicrobial therapy was appropriate. However, such a factor did not appear as an independent prognostic factor.