[Positive bronchoalveolar lavage and quantitative cultures results in suspected late-onset ventilator associated penumonia evaluation--retrospective study]

Introduction: Bronchoalveolar lavage (BAL) with quantitative cultures has been used in order to increase ventilator associated pneumonia (VAP) diagnosis specificity, although the accurate technique for this entity diagnosis remains controversial.

Objectives: To evaluate the influence of using positive BAL and quantitative cultures results in microbiologic diagnosis and treatment of patients with suspected late VAP and prior antibiotherapy.

Material and methods: Retrospective analysis of intensive care unit (UCI) patients, during a one year period, with clinical suspicion of late VAP and prior use of antibiotics that presented a growth in BAL cultures.

Results: Of 243 BAL performed, there were 71 (29.2%) positive cultures (60 patients, 76.7% male, 54 ± 19 years). BAL was done after 13 days (median) of invasive mechanical ventilation, 11 days of ICU antibiotherapy and in the day in which a new antibiotic for VAP suspicion was started. Colony forming units (CFU)/ml count was performed in 71.8% and endotracheal aspirate (ETA) simultaneously collected for qualitative analysis in 85.9%. Therapeutic approach was changed in 38.0%: correction (16.9%), de-escalation (12.7%) and directed antibiotherapy start (8.4%). Therapeutic changes were made in the presence of CFU > 10(4) in 84.2% and in agreement with ETA in 70.8%. In cases in which antibiotherapy was maintained (62.0%), quantitative cultures would have allowed de-escalation in 9.1%. Changes in prescription were more frequent when CFU was > 10(4) (48.5%), comparing with situations in which counts were lower and BAL analysis was qualitative (28.9%), p = 0.091. There were no significant differences between patients submitted to different therapeutic approaches concerning to ICU mortality or length of stay.

Conclusion: In late onset VAP, positive BAL and quantitative cultures allowed therapeutic changes, leading to antibiotic adequacy and consumption reduction, which can however be maximised.