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October 14, 2007
9:00 AM - 11:00 AM
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Accidental Insertion of LTS II into the Trachea in the Patients with Elective General Anesthesia
Yoshinori Kamiya, M.D., Ph.D., Tatsuaki Kikuchi, M.D., Ph.D., Tsuyoshi Ohtsuka, M.D., Takahisa Goto, M.D., Ph.D.
Anesthesiology and Critical Care Medicine, Yokohama City Univ. Grad. Sch. Med, Yokohama, Kanagawa, Japan
Introduction: The LTS II (Laryngeal Tube Suction II) is a new supraglottic device with a channel for the gastrointestinal tube, which has substantially longer shaft, thinner tip and oval-shaped distal cuff than the ”classic” LT and LT Sonda (LTS). Here we report four cases where the LTS II was misplaced in the trachea in the 50 consecutive anesthetized patients who underwent urological minor surgery. Cervical fluoroscopic image revealed the mechanism why LTS II easily misplaced in the airway but not esophagus compared to the ”classic” LT .

Method: After approval of the institutional review board and written, informed consent was obtained, 50 adult ASA 1-2 patients undergoing urological minor surgery (prostate brachytherapy) underwent standardized induction of anesthesia (propofol, 1mg/kg; fentanyl,. 3μg/kg; vecuronium, 0.08mg/kg). The size of LTS II was decided as manufacturer's recommendation. Patients' head were positioned in the sniffing position and an LTS II (size 4) was inserted according to the manufacturer's instruction. During insertion, we performed cervical fluoroscopy for checking whether LTS II was placed at correct positioning of the larynx.

Results: A little resistance was felt when the LTS II was inserted up to the depth where the Teeth Mark on the shaft of the LTS II met the incisors (i.e., the average depth for proper placement) for almost all patients who were inserted the LTS II. When the cuffs were inflated with 80 ml of air and positive pressure ventilation was started, a major air leakage was noted at the airway pressure of approximately 10 to 15 cmH2O in 4 out of 50 patients. Some degree of ventilation was possible in 3 of 4 patients. A cervical fluoroscopy revealed that the tip of the LTS II was in the vestibule of vocal cord or trachea. In these patients, the LTS II was removed immediately and ventilation was promptly restored using another airway. The detailed examination of fluoroscopic movies revealed how the LTS II entered in the trachea in another patient. When the LTS II was introduced into the pharyngeal space, its tip hit the posterior wall of the pharynx and was bent upward (i.e., ventrally, Fig. LTS II a,b). When the LTS II was advanced further, this ventral bending was maintained and the tip moved toward the vocal cords (Fig. LTS II c), resulting in misplacement in the trachea. When the original LT was used in the same patient, such bending of the tip did not occur, and the LT entered the esophagus(Fig. LT). We speculate that the slimmer and more pointed distal end of the LTS II compared to the original LT makes the LTS II more prone to bending when pushed against the posterior pharyngeal wall.

Conclusion: The four cases reported here raise the concern that the LTS II is associated with a greater risk of tracheal misplacement compared to its preceding versions such as the LT and the LTS. When extra resistance is felt during insertion of LTS II, the possibility of tracheal misplacement should be considered. Further studies appear warranted regarding the safety of LTS II.[figure1]

Anesthesiology 2007; 107: A591
Figure 1