Predictive Factors of Good Pulmonary Penetration of Antibiotics : AntiBiotics Dosage in Broncho-Alveolar Lavage

Overview

Respiratory infections are common and sometimes very severe. An insufficient dosage of the antibiotic could lead to a treatment failure A correct plasmatic antibiotic concentration is not a guarantee of a clinical success as it could not be a reflect of pulmonary concentration. The aim of this study is to determinate the predictive factors of pulmonary penetration of antibiotics in patients with a beta lactamines failure and who undergoes a flexible bronchoscopy.

To check if pulmonary concentrations of antibiotic are enough we will measure antibiotic concentration in the broncho-alveolar lavage (BAL). This technique which is clinically relevant and reliable could determinate the pulmonary diffusion level for antibiotics by calculating the ratio between plasmatic and intra-alveolar antibiotic concentration. This ratio will be correlated with potential limitation factors of pulmonary diffusion as respiratory diseases (COPD, cystic fibrosis, fibrosis…), sepsis, hypoalbuminemia. We have chosen to study the beta lactamin antibiotics because they are the most frequently used in pneumonia. Moreover, the beta lactamins pulmonary diffusion is likely to be the lowest. Finally, for patients with a known pathogen, we will divide this pulmonary concentration with minimal inhibitory concentration (MIC). Indeed, in severe pneumonia, to be sure of bactericidal activity, a pulmonary concentration of beta lactamines should be always higher than 4 to 5 times MIC.

Conditions