Figure 6-6 Mucociliary clearance measured as tantalum clearance in patients undergoing surgery with general or local anesthesia (i.e., awake). Notice the decrease in mucociliary clearance in the peripheral and central airways during halothane and thiopental anesthesia. (Adapted from Forbes AR, Gamsu G: Mucociliary clearance in the canine lung during and after general anesthesia. Anesthesiology 50:26, 1979.)