Ventilator Associated Pneumonia (Sub-Category)

Diagnosis of ventilator-associated pneumonia by bacteriologic analysis of bronchoscopic and nonbronchoscopic "blind" bronchoalveolar lavage fluid

J Pugin
R Auckenthaler
N Mili
JP Janssens
PD Lew
PM Suter

ABSTRACT

 

Substantial efforts have been devoted to improving the means for early and accurate diagnosis of ventilator-associated (VA) pneumonia in intensive care unit (ICU) patients because of its high incidence and mortality.  A good diagnostic yield has been reported from quantitative cultures of bronchoalveolar lavage (BAL) fluid or a protected specimen brush, both obtained by fiberoptic bronchoscopy.  As bronchoscopy requires specific skills and is costly, we evaluated a simpler method to obtain BAL fluid, that is by a catheter introduced blindly into the bronchial tree.  Quantitative cultures from bronchoscopically sampled BAL (B-BAL) and blindly nonbronchoscopically collected BAL (NB-BAL) were assessed for sensitivity, specificity, and predictive value for the diagnosis of VA pneumonia.  A total of 40 pairs of samples were examined in 28 patients requiring prolonged mechanical ventilation and presenting a high risk of developing pneumonia.  For comparison with bacteriologic data, we defined a clinical score for pneumonia ranging from 0 to 12 using the following variables:  body temperature, leukocyte count, volume and character of tracheal secretions, arterial oxygenation, chest X-ray, Gram stain, and culture of tracheal aspirate.  To quantify the bacteria in BAL, the bacterial index (BI) was used, defined as the sum of the logarithm of the number of bacteria cultured per milliliter of BAL fluid.  A good correlation between clinical score and quantitative bacteriology was observed (r = 0.84 for B-BAL and 0.76 for NB-BAL; p less than 0.0001).  Similar to studies in baboons, patients with pulmonary infection could be distinguished by a BI greater than or equal to five with a sensitivity of 93% and a specificity of 100% (B-BAL).

PubMed Link to Article:

Pugin J, Auckenthaler R, Mili N, Janssens JP, Lew PD, Suter PM. Diagnosis of ventilator-associated pneumonia by bacteriologic analysis of bronchoscopic and nonbronchoscopic "blind" bronchoalveolar lavage fluid. Am Rev Respir Dis. 1991 May;143(5 Pt 1):1121-9. PubMed PMID: 2024824.