The adequacy of timely empiric antibiotic therapy for ventilator-associated pneumonia: an important determinant of outcome.

OBJECTIVE: The individual impact of timeliness vs adequacy of empiric antibiotic therapy for a clinical suspicion of ventilator-associated pneumonia (CSVAP) is unknown. Accordingly, in patients with CSVAP and timely initiation of empiric antibiotic therapy, we determined the impact of inadequate therapy (IT).

METHODS: Analysis of a randomized trial of CSVAP treated empirically with meropenem or meropenem plus ciprofloxacin was done. Adequate therapy (AT) was considered present if all pathogens in the index culture were sensitive to the empiric antibiotics; IT was defined as the presence of pathogens resistant to the empiric antibiotics. A priori, for Pseudomonas sp, 2 antibiotics with activity against the organisms were required for AT to be considered present.

RESULTS: Of 739 patients with CSVAP, 350 had positive cultures: 313 (89.4%) had AT, and 37 (10.6%), IT. The IT group had higher intensive care unit (35.1% vs 11.8%, P = .0001) and hospital mortalities (48.7% vs 19.5%, P < .0001), increased mechanical ventilation (15.8 vs 6.8 days, P = .0005), intensive care unit stay (13.5 vs 8.4 days, P = .02), and hospital stay (42.2 vs 27.9 days, P = .04). In multivariate analysis and a separate case control analysis, the odds ratio of hospital mortality with IT was 3.05 (95% confidence interval, 1.25-7.45; P = .01) and 3.00 (95% confidence interval, 1.24-7.24; P = .01), respectively.

CONCLUSION: In the context of early administration of empiric broad spectrum antibiotics for CSVAP, IT is associated with higher morbidity and mortality.