Observations on the cytology of tracheobronchial secretions collected by a new technique.

Expectorated sputum and secretions aspirated through the bronchoscope frequently contain contaminants from the oral cavity.1 Because of this, it has not been possible often to accurately determine the cytology of the tracheobronchial tree in normal or diseased patients. Carabelli2 after studying secretions obtained by bronchoscopic aspiration reported that they normally contained ciliated columnar, goblet, undifferentiated bronchial, and squamous cells in addition to macrophages. He attributed blood elements to trauma, and did not consider them a part of the normal cytogram. Moreover, he believed that squamous cells probably represented elements which had been aspirated deep into the bronchial tree, presumably from the supraglottic region. For this reason little importance was attributed to their presence. In suppurative bronchopneumonitis he found leukocytes prominent and predominating. It has been our experience1 that under both normal and pathological conditions, in the absence of instrumentation, oral contents are rarely aspirated into the tracheobronchial tree.