Bronchial cuff pressur e

Purpose: The bronchial cuff pressures (BCPs) of left-sided double-lumen endobronchial tubes (DLTs) manufactured by Rusch and Mallinckrodt were measured in 80 patients when the tubes were withdrawn to compare the effect of tube design on BCP change. Methods: During general anesthesia with muscle relaxation, the cephalad surface of the endobronchial cuff was positioned either 2.5 cm distal to the carina (Rusch Group R-I; n = 20 and Mallinckrodt Group B-I; n = 20) or just below the carina (Rusch Group R- II; n = 20 and Mallinckrodt Group B- II; n = 20) and the cuff was inflated to 35 cm H 2 O. The tube was then withdrawn in 0.5-cm steps until the cuff was 2.0 cm proximal to the carina, the position just before the capnogram or pressure-volume loop of tracheal lumen changed. The BCP at each step was measured. The rate of decrease in BCP was defined as the decrease of BCP divided by the length of displacement of DLT. Results: The rates of decrease from the +2.5 cm position to the end point in Group B-I (7.7 ± 0.8 cm H 2 O·cm 1 ) and those from the most proximal acceptable position to the end point in Group B-II (19.5 ± 4.8 cm H 2 O·cm 1 ) were greater than those in Group R-I (6.9 ± 0.9 cm H 2 O·cm -1 ) (P < 0.01) and in Group R-II (12.4 ± 3.1 cm H 2 O·cm -1 ) (P < 0.01), respectively.