- Journal club critique
- Open Access
No sampling technique was superior for the diagnosis of ventilator-associated pneumonia
© BioMed Central Ltd 2005
- Published: 14 February 2005
Wood AY, Davit AJ II, Ciraulo DL, et al. A prospective assessment of diagnostic efficacy of blind protective bronchial brushings compared to bronchoscope-assisted lavage, bronchoscope-directed brushings, and blind endotracheal aspirates in ventilator-associated pneumonia. J Trauma 2003, 55:825–834.
The diagnosis of ventilator-associated pneumonia (VAP) has proven to be a challenging task. Studies comparing invasive and non-invasive diagnostic approaches are lacking.
The use of a blind protected brush is equivalent to bronchoscope-directed techniques in determining the microbiology of VAP, while endotracheal aspirates are contaminated with oropharyngeal flora and of little value.
Single center, prospective cohort study.
Level 1 trauma center at an academic medical center.
Ninety trauma patients who were mechanically ventilated for at least 48 hours and deemed to have clinical indications suggestive of pneumonia (new infiltrate on chest radiograph, excessive or purulent respiratory secretions, suspected aspiration, fever (>38.2°C), leukocytosis (>12,000/mm3), or respiratory distress of unknown cause).
Four samplings were performed on each patient in the following order: blind protected brush (BPB), bronchoscopic-directed protected brush (BDPB), bronchoalveolar lavage (BAL), and endotracheal aspirates (ETA). Procedures were performed from least to greatest degree of invasiveness to avoid contamination of lower airways, except for ETA.
With patients serving as their own controls, quantitative cultures were obtained using each sampling technique. BDPB and BAL were set as the "gold standards" for comparison against each other and with BPB and ETA. Kappa analysis was used to measure the strength of agreement between techniques. Results were stratified by type of organism.
BPB had the highest strength of agreement with both BAL and BDPB (κ = 0.547 and κ = 0.467, respectively). The strength of agreement between techniques was moderate to good for gram-negative cocci and fair to poor for gram-negative rods and gram-positive cocci. Comparing the growth of specific pathogens, Haemophilus, Klebsiella, Escherichia, Acinetobacter, and Streptococcus correlated well across the majority of techniques, while Enterobacter agreement was consistently poor to fair.
Using BDPB as the gold standard, BPB was found to have the highest sensitivity (91.1%) and specificity (89.8%). Sensitivities overall were higher when using BAL as the gold standard across all modalities. Kappa analysis comparing blind samples obtained from the same vs. the opposite side of the radiographic infiltrate found no differences between sides.
A quantitative analysis of bacteriologic cultures obtained by four standard sampling techniques demonstrated with statistical significance that no difference exists between techniques in terms of reliability or obtaining clinically significant pathogens.
Until compelling data are produced showing a particular sampling technique is superior, we recommend a VAP management strategy[7, 9] that includes: a) initial evaluation with quantitative microbiology of respiratory secretions and immediate initiation of antimicrobial agents, and b) reevaluation within 2 to 3 days with adjustment or discontinuation of antimicrobials based on clinical course, culture results, and whether any noninfectious or nonpulmonary etiologies have been identified.
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