BRONCHOSCOPIC OR BLIND SAMPLING TECHNIQUES FOR THE DIAGNOSIS OF VENTILATOR-ASSOCIATED PNEUMONIA

The purpose of this prospective postmortem study was to assess the dia gnostic accuracy of bronchoscopic techniques (bronchoalveolar ravage [ BAL] and protected specimen brush [PSB]) and nonbronchoscopic techniqu es (blind bronchial sampling [BBS] and mini-BAL) in the diagnosis of v entilator-associated pneumonia (VAP). The results of each technique we re compared with histology and culture of lung tissue specimens obtain ed by surgical pneumonectomies in 38 patients who died after at least 72 h of mechanical ventilation. Histology was positive for VAP in 18 p atients and negative in 20 patients. There were 12 definite VAP (posit ive histology and positive lung cultures) and 6 histologic VAP (positi ve histology and negative cultures). Clinical pulmonary infection scor e (CPIS) at a threshold of 6 achieved a sensitivity of 72% and a speci ficity of 85%. When the CPIS was combined with the logarithmic concent ration of the predominant microorganism obtained from the BBS sample c ulture, specificity was increased to 95%, for a threshold of 10. Using 10(3) cfu/ml as the threshold of positivity for cultures obtained wit h PSB and mini-BAL samples and 10(4) cfu/ml for cultures obtained with BBS and BAL, the respective sensitivities of these techniques for def inite VAP were 42, 67, 83, and 58%. The sensitivity of BBS was signifi cantly higher than that of PSB (p < 0.05). The area under the receiver operator characteristic curve was significantly greater for BBS than PSB (p < 0.05). Given that it is more sensitive and noninvasive, BBS i s preferable to PSB for the diagnosis of VAP.