Postoperative impairment of mucous transport in the lung.

Impairment of mucous transport is considered significant to the postoperative development of atelectasis, but the association has never beed demonstrated in humans. Tantalum powder, which adheres to airway mucus, can be used to study mucociliary transport. The postoperative clearance of insufflated tantalum powder (mean diameter, 2.5 mum) was investigated in 25 patients. Eighteen patients underwent intra-abdominal vascular surgery and 7 undersent lower-extremity orthopedic procedures. At the completion of surgery, tantalum was insufflated into both lungs of each patient to outline a representative sample of airways from the trachea to the small bronchi. Tantalum clearance was evaluated from serial radiographs obtained immediately after insufflation, at approximately 6, 18, 26, and 48 hours later, and thereafter whenever appropriate. In the 7 orthopedic patients, clearance of tantalum was progressive and usually complete within 48 hours. Atelectasis did not occur in this group. In 14 of the 18 patients who had abdominal surgery, mucociliary clearance was markedly abnormal in that tantalum was retained for up to 6 days. Pooling of tantalum-labeled mucus occurred in dependent bronchi in 16 of these 18 patients. Pooling preceded and always accompanied radiographically visible atelectasis. Lobar atelectasis occurred in 6 patients and segmental atelectasis in 8. Tantalum-labeled mucus moved peripherally in atelectatic lobes or segments and was retained in these bronchi until re-expansion took place. Thus, impaired ciliary function and mucous transport are associated with and implicated in postoperative pulmonary atelectasis.