[Intrapulmonary inflammatory response in critically ill patients with pneumonia]

Abstract

Objective: to evaluate the relationship between the microbiology result and cytokine expression in bronchoalveolar lavage (BAL).

Design: An observational, prospective study.

Setting: a 17-bed medical and surgical intensive care unit.

Patients: Mechanically-ventilated patients with suspected pneumonia admitted to the ICU during a 27-month time period were consecutively enrolled.

Interventions: BAL was performed with 150ml sterile isotonic saline solution in three aliquots of 50ml. Local anesthetics were not used during the procedure. A BAL sample was processed for a microbiologic quantitative culture and BAL cytokines IL-6, IL 8, TNFα, granulocyte colony-stimulating factor (G-CSF) and granulocyte-monocyte colony-stimulating factor (GM-CSF) were measured.

Main variables of interest: age, APACHE II score within the first 24 hours of admission, time on mechanical ventilation, ICU length of stay, mortality, previous antibiotic therapy, isolated bacteria and cytokines concentration were analyzed.

Results: fifty-nine consecutive patients were included, and most of the patients (79.7%) had prior antibiotic therapy. Twenty-two patients (37.2%) had a positive BAL. In the group of patients with positive BAL, the TNFα concentration was significantly higher in the group of patients with positive BAL than in the BAL negative group.

Conclusions: there is a significant correlation between the microbiology result and the TNFα concentration in the BAL fluid. In mechanically-ventilated patients, TNFα in BAL has been associated with positive cultures despite prior antibiotic therapy.