Con: Proper Positioning of a Double-Lumen Endobronchial Tube Can Only Be Accomplished With the Use of Endoscopy

T HE GREAT advantage of double-lumen tubes (DLTs) in thoracic surgery is that either or both lungs can be ventilated independently while isolating each lung. Unfortunately, because of problems with their accurate placement, many anesthesiologists do not use these tubes as often as they should. Since a misplaced DLT can result in hypoxemia, airway trauma, and unsuitable surgical conditions, many experts recommend that endoscopy always be performed to ensure their proper positioning. In my opinion, if you choose the appropriate DLT and understand the information easily obtained by carefully listening to breath sounds during their placement, fiberoptic bronchoscopy is seldom, if ever, needed. The three most common positioning complications associated with DLTs are not passing the tube sufficiently far down into the bronchus, intubation of the wrong bronchus, and passing the tube too deep into the correct bronchus resulting in upper lobe obstruction. All these problems can be easily recognized without bronchoscopy by using the following simple technique for DLT placement.’ Following induction of anesthesia, the tip of the DLT is advanced just past the vocal cords, the stylet in the endobronchial lumen is removed, and the tube is rotated 90” in the direction of the bronchus to be intubated. Since most anesthesiologists prefer a left-sided DLT for either right or left thoracotomy, the steps for left endobronchial intubation will be described. The tube should be advanced until moderate resistance to further passage is encountered. Both the tracheal and endobronchial cuffs are then inflated with air. It is essential that a large DLT be used. Men should be intubated with a 41F and most women with a 39F polyvinylchloride (PVC) DLT. Only 1 to 2 mL of air should be needed for the bronchial cuff. If more than 3 mL of air is required to seal the bronchus, the bronchial cuff is either herniating above the carina or may be completely in the trachea. A bronchoscope is not needed to recognize a tube that is not deep enough. The patient should be ventilated with both cuffs still inflated. With a clear PVC DLT, moisture should appear in both lumens. The chest wall is observed for equal movement and is auscultated with special attention for any differences in breath sounds over the left upper and lower lung fields. Next, the tracheal lumen should be occluded with a surgical clamp. Breath sounds should now be heard only over the intubated left lung. If breath sounds are present bilaterally, the tube is far too high in the trachea. If breath sounds are heard only over the right lung while ventilating through the endobronchial lumen, the tube is down the wrong side. This problem is easily remedied by deflating both cuffs, pulling the tube back until its tip is above the carina, and rotating it to the left while again advancing it until resistance is encountered. The left endobronchial lumen should then be clamped and the patient ventilated. Breath sounds should be heard only over the right lung. If there is now difficulty ventilating through the tracheal lumen with a marked resistance to air flow with both cuffs inflated, the tube is either too far into the left bronchus or still not deep enough. At this point, the tube’s position can be determined, without bronchoscopy, by deflating only the endobronchial cuff while continuing to ventilate only through the tracheal lumen with the left (endobronchial) lumen occluded. If the tube is too deep into the left bronchus, breath sounds will now be heard only on the left (Fig 1). If the tube is not deep enough into the bronchus, breath sounds will now be heard bilaterally (Fig 2). Both cuffs should be deflated and the DLT advanced or withdrawn depending on the results of the previous maneuver. Once this sequence of steps is understood, a DLT can be quickly, safely, and accurately positioned in less than a minute. It is important that