Techniques for Exchanging a King Laryngeal Tube For an Endotracheal Tube

Case Presentation

A 57-year-old man was brought to the emergency department by emergency medical technicians after a motor vehicle accident. The patient had sustained head and facial trauma. His Glasgow Coma Scale score at the scene of the accident was 7. Two attempts to intubate the trachea with an endotracheal tube (ETT) failed and caused upper airway bleeding. A laryngeal tube, the King LTS-D, size 4 (Ambu), was successfully placed by the emergency medical technician on the first attempt and ventilation started. On arrival at the hospital, intraabdominal bleeding was suspected and the patient was transported to the OR for emergent exploratory laparotomy. It was decided to attempt to replace the King LT with an ETT and prepare for a surgical airway as a backup option.

The Laryngeal Tube (VBM Medizintechnik, Sulz, Germany) was launched in the United States in 2004, as a disposable device by King Systems (later acquired by Ambu) under the name “King LT.”¹ The King disposable LT (LT-D) is increasingly used by prehospital providers as either a primary airway device or a rescue device for difficult airways. To establish a definite airway, anesthesiologists can be tasked with the exchange of a King LT-D for an ETT. A safe exchange requires familiarity with the device.

The King LT-D is a disposable, supraglottic airway device (SAD) with an oropharyngeal and esophageal cuff and a single inflation port. It is inserted blindly into the esophagus and has 2 ventilation outlets located between the cuffs. Due to its S-shaped design, the likelihood of tracheal insertion is minimal (Figure).¹ King LTS-D (S for suction) is a second-generation SAD with a separate channel allowing for passage of a gastric tube and evacuation of stomach contents. Incorrect use of the King LTS-D from either cuff overinflation or prolonged use may result in upper airway trauma or pharyngeal, glottic and lingual edema.^2-4

Removing the King LT-D or LTS-D before securing the airway can result in a life-threatening “cannot intubate, cannot oxygenate” (CICO) situation. Multiple techniques that facilitate endotracheal intubation with the original King LT in situ have been described.^4-9 In a retrospective study of 48 patients arriving at an emergency department with their airway already secured with a King LT, Subramanian et al reported that 29% of patients required surgical tracheostomy to establish a definite airway.⁴ Nonsurgical techniques to exchange the King LT for an ETT included direct and video laryngoscopy, flexible bronchoscopy, and use of an Arndt airway exchange catheter (Cook Medical).⁴

Facilitating Exchange With a Fiber-optic Bronchoscope

The King LT and its variants can be exchanged for an ETT using an extraluminal or intraluminal fiber-optically guided technique.⁸ In the extraluminal technique, the fiber-optic bronchoscope, preloaded with an ETT, can be used orally or nasally and inserted alongside the King LT, after partially deflating the cuffs, and maneuvered into the trachea.⁷ In the intraluminal approach, the fiber-optic bronchoscope is preloaded with an Aintree intubating catheter (AIC, Cook Medical) and then passed into the trachea through the ventilation channel of the King LT. Once the correct placement of the AIC is confirmed fiber-optically, the AIC is left in the trachea while the fiber-optic scope and King LT are removed. An ETT is then railroaded over the AIC into the trachea.

Budde et al compared the intraluminal and extraluminal oral techniques to exchange a King LT in a mannequin.⁸ They found an 86% success rate for both approaches. However, the intraluminal technique was significantly faster than the extraluminal technique (101±85 sec vs 142±85 sec).⁸

One of the disadvantages of the intraluminal technique is a potential inadvertent expulsion of the AIC. In addition, it may be difficult to maintain oxygenation and ventilation with the intraluminal exchange technique. A bronchoscopy adapter may help to overcome this problem, but it extends the length of the ventilation tube of the laryngeal tube and should be removed before the King LT-D or LTS-D is withdrawn, to reduce the risk for AIC expulsion. Although the extraluminal technique offers the possibility of continuous oxygenation and ventilation, it can be problematic in an emergency situation, because it requires more time to complete the exchange. In addition, secretions or blood in the upper airway could affect the visualization of the glottis. Matioc and Genzwuerker described an intraluminal exchange technique using an Arndt exchange catheter set through a fiber-optic bronchoscope.⁹

Video Laryngoscopic–Facilitated Exchange

Video laryngoscopy has been used successfully to facilitate exchange of the King LT for an ETT with or without airway adjunct devices.^4-6 Dood et al reported a high success rate of using a bougie introduced into the trachea under video laryngoscopic guidance, while the King LT is left in place.⁶ The video laryngoscope was inserted anterior to the King LT while the tube’s cuffs were kept inflated, allowing for continued oxygenation and ventilation. The bougie was inserted into the trachea under direct visualization after cuff deflation. In case of failure to intubate the trachea with an ETT, the ventilation can be switched back to the King LT after reinflating the cuff.6 El-Orbany described an exchange technique using video laryngoscopy combined with extraluminal fiber-optic bronchoscopy.10

Resolution of the Case

On arrival to the OR, the patient was adequately oxygenated and ventilated through the King LT. An 18-Fr gastric tube was inserted through the gastric channel to drain the stomach. After deflating the cuffs of the King LTS-D, video laryngoscopy with a GlideScope (Verathon) was attempted, but the vocal cords could not be visualized due to upper airway edema and bleeding. The cuffs were reinflated and ventilation was resumed. The King LTS-D was successfully exchanged for an ETT using an intraluminal fiber-optic exchange technique, facilitated by an AIC, in 90 seconds.

Conclusion

Although it is possible to maintain an airway with a SAD for longer periods of time, an exchange to an ETT is often necessary, according to clinical need. Removing a functional King LT-D or LTS-D placed in the prehospital setting and attempting laryngoscopy is not recommended, especially if the insertion of the laryngeal tube was preceded by failed endotracheal intubation. There is no standardized method to safely exchange a King LT-D or LTS-D for a definitive airway. However, there are several methods to exchange a King LT-D or LTS-D for an ETT while maintaining oxygenation and ventilation, all of which require advanced airway equipment and an experienced anesthesiologist to safely complete the procedure.

References

1. Vaida S, Gaitini L, Frass M. Supraglottic airway techniques: nonlaryngeal mask airways. In: Hagberg C, Artime C, Aziz M, eds. Hagberg and Benumof’s Airway Management, 4th edition. Philadelphia, PA: Elsevier; 2018:355-361.
2. Brimacombe J, Keller C, Roth W, et al. Large cuff volumes impede posterior pharyngeal mucosal perfusion with the laryngeal tube airway. Can J Anaesth. 2002;49(10):1084-1087.
3. Gaither JB, Matheson J, Eberhardt A, et al. Tongue engorgement associated with prolonged use of the King-LT laryngeal tube device. Ann Emerg Med. 2010;55(4):367-369.
4. Subramanian A, Garcia-Marcinkiewicz AG, Brown DR, et al. Definitive airway management of patients presenting with a pre-hospital inserted King LT(S)-D laryngeal tube airway: a historical cohort study. Can J Anaesth. 2016;63(3):275-282.
5. Schalk R, Weber CF, Byhahn C, et al. Reintubation using the C-MAC videolaryngoscope. Implementation in patients with difficult airways initially managed with in situ laryngeal tubes [in German]. Anaesthesist. 2012;61(9):777-782.
6. Dodd KW, Klein LR, Kornas LR, et al. Definitive airway management in emergency department patients with a King laryngeal tube in place: a simple and safe approach. Can J Anaesth. 2016;63(5):638-639.
7. Genzwuerker HV, Vollmer T, Ellinger K. Fibreoptic tracheal intubation after placement of the laryngeal tube. Br J Anaesth. 2002;89(5):733-738.
8. Budde AO, Schwarz A, Dalal PG, et al. Comparison of 2 techniques of laryngeal tube exchange in a randomized controlled simulation study. Am J Emerg Med. 2015;33(2):173-176.
9. Matioc AA, Genzwuerker HV. Why go blind when you can see? J Emerg Med. 2012;42(6):702-703.
10. El-Orbany M, Schmid P 3rd. Combined use of flexible bronchoscopy and video laryngoscopy for endotracheal intubation in patients with King laryngeal tube in situ. Can J Anaesth. 2016;63(10):1201-1202.