To the Editor:-Conventional double lumen intrabronchial tubes are designed for insertion through the oral cavity. They are not designed for use through a tracheal stoma.
In a previous report, Brodsky et al. reported a development of a tracheostomy double-lumen tube. However, it was not designed for patients with permanent stoma, and we have encountered circumstances in which the tube did not fit the patient's trachea and bronchus well. We have, therefore, developed a new tube for use in such patients.
Composition of the Tube and Its Assembly
The new endobronchial tube is a silicon, spiral, wire-reinforced double-lumen tube (Figure 1). The tube was made in three individual parts-the distal section beyond the tracheal orifice, the middle section between the tracheal cuff and the point of bifurcation, and the proximal bifurcated part-and assembled later. Assistance with the design and all tube construction and fabrication work was performed by Koken Medical (Shinjuku-ku, Tokyo, Japan).
The Middle Section
The middle section of the tube is the trunk. It is constructed of two thin-walled silicon tubes that are glued together with an inner diameter of 5.0 mm, reinforced with a stainless spiral wire, and covered in a silicon coating. Two pilot balloons were included that ran within the walls of the two inner tubes, one of which exited the wall of the tube to supply the tracheal cuff, which also is made of silicon.
The Distal Section
The distal section, containing the bronchial lumen and the cuff, is also constructed of wire-reinforced silicon. The dimensions are based on the Mallinckrodt double-lumen tube. The bronchial cuff is located 1.2 cm from the tip, and the distance between the tip orifice and the tracheal orifice is 4.9 cm. This section initially was made of polyvinyl chloride, but we found it to be too stiff. We, therefore, changed the material to silicone that was reinforced with wire to avoid excessive flexibility (Figure 2).
The Proximal Part
The proximal part connects the double-lumen airway to the anesthetic circuit. This part is made of two cone-shaped tubes. The connection of these two tubes and the mid part are bound with a silicone sheet and a silicone paste (Figure 3). The diameters of the two inner lumens are larger than 5.0 mm. The most proximal lumen has an inner diameter of 9.0 mm.
Because of the size of most patients, we have made only a left-sided 39-French double-lumen tube. The narrowest inner diameter of either lumen is 5.0 mm. The largest outer diameter of the whole tube is 1.3 cm.
With approval from the Ethics Committee of the National Cancer Center Hospital, we tested this new tube in seven patients with permanent tracheostomies. Six of seven were scheduled to undergo lobectomy or bullectomy, and one patient had a mediastinal abscess which developed after a previous esophagectomy. After induction of general anesthesia, the new double-lumen tube was inserted via the stoma. In patients, we used the left-sided tube. When the tracheal cuff just disappeared inside the stoma, we inserted a thin endoscope through the tube to facilitate further positioning of the endobronchial tube. With the guidance of the endoscope, the endobronchial tube was positioned such that the blue endobronchial cuff was just below the carina. In all seven patients, proper placement cuff was achieved during the first attempt. The whole procedure of intubation and bronchoscopy was accomplished within 10 min. The tube was secured with surgical thread at the patient's stoma. In six patients, bronchial cuff inflation was unnecessary because the airway was sealed satisfactorily. In one patient, we inflated the bronchial cuff with 1 ml air.
During induction of anesthesia, the tubes functioned well with no sign of kinking, no movement, and easy passage of the suction catheter. After extubation, the airway was suctioned carefully using a large endoscope. We saw no sign of gross irritation during endoscopy.
We conclude that this newly designed double-lumen tube may be advantageous in caring for patients with permanent tracheal stomas. We are in the process of developing a commercial version of this tube.
Toshiyuki Saito, M.D.
Tsuguo Naruke, M.D.
Edward Carney, Ph.D.
Yoko Yokokawa, M.D.
Kazuaki Hiraga, M.D.
Department of Anesthesia; National Cancer Center Hospital; Kagawa, Chigasaki-City, Kanagawa, Japan;firstname.lastname@example.org
Christer Carlsson, M.D., Ph.D.
Director in Anesthesia; Malmo Hospital; Lund University; Malmo-City, Sweden
Presented in part at the Annual Meeting of the American Society of Anesthesiologists, San Diego, October 22nd, 1997.
(Accepted for publication May 15, 1998.)