Describe the proper technique for placing a double-lumen endobronchial tube.
The largest size Robertshaw-type double-lumen tube that can easily pass the glottis is chosen. The larger the tube size, the less air that is required for endobronchial tube cuff inflation; the larger the lumen for suctioning; and the less likelihood of tube malposition distally in the bronchus. Clear polyvinylchloride disposable Robertshaw-type endo-bronchial tubes are available in sizes 41, 39, 37, 35, and 28 French (French size = external diameter of tube in mm ×3). Sizes 39 and 37 French fit most adults.
Curved laryngoscope blades usually provide more space in the mouth than straight blades for passage of double-lumen tubes, which are bulky compared with single-lumen tubes. In some patients, however, a straight blade may be required.
Induction agents are selected based on the patient’s med-ical condition. Nondepolarizing muscle relaxants offer the advantage of longer duration of action than succinylcholine. This allows for prolonged duration of muscle relaxation, which facilitates double-lumen tube placement without repeat doses of nondepolarizing agent.
This double-lumen tube is placed through the mouth with its distal concave curve pointed anteriorly. After the endobronchial cuff passes the vocal cords, an assistant removes the stylette. The tube is rotated 90° toward the side of intended intubation and advanced until resistance is encountered. Alternatively, the endobronchial lumen can be advanced over a flexible fiberoptic laryngoscope into the appropriate bronchus. Air is injected into the tracheal cuff, and the tube’s position is checked.