THE VALUE OF ROUTINE MICROBIAL INVESTIGATION IN VENTILATOR-ASSOCIATEDPNEUMONIA

The use of microbiologic investigations in routine clinical practice, their value in guiding antibiotic prescription, and their influence on outcome were prospectively studied in 113 consecutive adults who deve loped ventilator-associated pneumonia (VAP). Blood cultures were perfo rmed in 78.7% of cases, protected specimen brushing in 95.5%, and bron choalveolar lavage in only 45.1%. No causative agent was identified in 13 episodes (11.5%), and results of microbial tests directed a change in therapy in 43 (38.0%). Bronchoscopic results revealed inadequate i nitial selection of antibiotic therapy in 27 cases (23.9%) and led to a change in antibiotic treatment. Inadequate initial selection was sti ll associated with a significantly greater increase in related mortali ty than adequate initial therapy (37.0% versus 15.4%, p < 0.05), altho ugh the change in therapy permitted clinical resolution in 17 (62.9%) of these 27 episodes, and 10 patients were discharged alive. Bronchosc opic results also permitted the reduction of the antibiotic spectrum i n seven episodes (6.1%). This study suggests that in patients with VAP , bronchoscopic results ape frequently associated with changes in anti biotic therapy, Nevertheless, our findings also emphasize the critical importance of an appropriate early antibiotic therapy.