The safety and diagnostic accuracy of minibronchoalveolar lavage in patients with suspected ventilator-associated pneumonia

Objectives: To assess the safety of minibronchoalveolar lavage done by respiratory therapists for the evaluation of suspected ventilator-associated pneumonia and to determine the diagnostic agreement between quantitative lower airway cultures obtained by the minibronchoalveolar lavage and protected specimen brush techniques. Design: A prospective direct comparison of two diagnostic techniques. Setting: An academic tertiary care center in St. Louis, Missouri. Patients: 72 consecutive patients suspected of having ventilator-associated pneumonia on the basis of clinical evidence. Interventions: Sampling of lower airway secretions using the protected specimen brush and minibronchoalveolar lavage techniques. Main outcome measures: Clinical complications and quantitative cultures of respiratory secretions. Results: 72 patients suspected of having ventilator associated pneumonia (first episode) were evaluated using minibronchoalveolar lavage. In 42 patients, lower airway secretions were also obtained using the protected specimen brush technique. No change in arterial blood oxygen saturation or heart rate occurred after minibronchoalveolar lavage (P > 0.2). Mean arterial pressure slightly increased with minibronchoalveolar lavage (baseline mean pressure, 90.1 mm Hg [CI, 88.4 to 91.7 mm Hg]; average within-person change, 2.6 mm Hg; P = 0.024). Good diagnostic agreement was shown for quantitative cultures obtained with the protected specimen brush and minibronchoalveolar lavage techniques (kappa statistic, 0.63; concordance, 83.3%); 10³ colony forming units/mL was used as the threshold for a clinically significant culture result. Conclusions: Minibronchoalveolar lavage is a safe and technically simple procedure for obtaining quantitative lower airway cultures in patients requiring mechanical ventilation. Quantitative culture results obtained by minibronchoalveolar lavage are similar to those obtained by the protected specimen brush technique.