Prospective evaluation of the protected specimen brush for the diagnosis of pulmonary infections in ventilated patients.

To determine the relative cultural accuracy of the bronchoscopic protected specimen brush (PSB) in ventilated patients, we compared this method in the same area of the lung with histologic and bacteriologic examinations of pulmonary specimens. The procedures were concluded just after death when the ventilator was still functioning. Samples via the PSB were taken from a branch of the anterior basal bronchus of the left lower lobe, and immediate left thoracotomy was performed to obtain peripheral specimens from the corresponding segment for quantitative cultures. Twenty-six patients were studied; 6 had histologically proved pneumonia. Using quantitative cultures, a correlation was evidenced between PSB and lung cultures, especially in the subgroup of patients who received no antibiotic during the week preceding their death. No pneumonia was observed when PSB cultures isolated no organisms in concentrations greater than 10(3) colony-forming units (cfu) per ml. The PSB cultures at a level of 10(3) cfu/ml identified every patient with histologically proved pneumonia and every microorganism present in concentrations of 10(4) cfu/g or greater in the lungs. Moreover, in the subgroup of patients receiving no antibiotic, only 4 microorganisms were isolated by the PSB in concentrations greater than 10(3) cfu/ml and not found in the lung.(ABSTRACT TRUNCATED AT 250 WORDS)