Feasibility of the modified mini-bronchoalveolar lavage techniques using a nasogastric suction catheter and polytetrafluoroethylene bronchoscopic suction catheter in diagnosing bilateral pneumonia: a pilot study.

Abstract

The adequacy of actual lower respiratory tract samples collected using the current collection technique is debated. Endotracheal aspiration is commonly insufficient and can be contaminated with colonization from the proximal airway. Diagnostic bronchoscopy is the standard method for collecting specimens from the lower respiratory tract. However, it is usually unavailable in resource-limited settings. At present, noninvasive methods with the mini-bronchoalveolar lavage (BAL) catheter are used to collect specimens from the lower respiratory tract. Compared with the nasogastric (NG) tube, the polytetrafluoroethylene (PTFE) catheter, a modified mini-BAL catheter that suctions the more distal part of the tracheobronchial tree, can collect actual lower respiratory tract specimens. This prospective open-label pilot study included patients aged >18 years who were diagnosed with bilateral pneumonia and who required mechanical ventilation. Lower respiratory tract samples were collected via endotracheal aspiration, mini-BAL using an NG tube, and mini-BAL using a PTFE bronchoscopic catheter. Data on return fluid volume, white blood cell (WBC) count, microbiologic information obtained via quantitative culture, and each procedure-related complication were recorded. The return fluid volumes of the NG tube and PTFE groups were 50 and 40 mL, respectively. The median WBC counts were 245 cells/cumm3 in the NG tube group and 305 cells/cumm3 in the PTFE group. Culture from endotracheal aspiration detected polymicrobial organisms in 8 (20.0%) patients. Further, 19 (47.5%) patients in the NG tube group and 18 (45.0%) in the PTFE group presented with polymicrobial organisms. Approximately 10% of patients developed mini-BAL-related complications, including arrhythmia (2.5%), mild hypoxemia (2.5%), and mild bleeding (5.0%). The two modified mini-BAL techniques are feasible in diagnosing patients with pneumonia requiring mechanical ventilation. The mini-BAL technique is more likely to detect polymicrobial organisms compared with endotracheal aspiration, which can then identify the causative polymicrobial organism of ventilator associated pneumonia (VAP) and lead to antibiotic adjustment. Moreover, it is easy to perform, can yield adequate specimens, and has few complications.