To the Editor:
The flexible laryngeal mask airway (FLMA) has been used for adenotonsillectomy , laser pharyngoplasty , and dental extraction . The long, flexible, narrow bore tube provides better surgical access to the oropharyngeal cavity than the standard laryngeal mask airway, but where perfect oral access is required nasotracheal intubation, is probably the technique of choice. A nasal laryngeal mask airway with a detachable tube and flanged cuff was designed and tested to overcome this limitation, but was considered too impractical for common clinical use . We describe a simple retrograde technique that allows the FLMA to be used as a nasal airway.
The FLMA is inserted using the standard technique, and an adequate airway is established. A Foley catheter is introduced through the nose and brought out through the mouth using Magill's forceps. The proximal connector is removed from the FLMA, the distal end of the catheter is inserted, and the balloon is inflated with saline to grip the inner walls of the FLMA tube. The catheter is then gently withdrawn from the nose while guiding the FLMA tube into the mouth with a finger. Once the FLMA tube starts to emerge from the nose, the tube/bowl junction of the FLMA is held in the laryngopharynx with the index finger while the FLMA tube is pulled out to length. The saline is withdrawn from the balloon, the catheter is removed, and the proximal connector is reattached. At the end of the procedure, the FLMA tube is either pulled back into the mouth with Magill's forceps or pushed back using a small cuffed tracheal tube gripping the inner FLMA tube. Anesthesia is then discontinued, and the patient emerges with the FLMA tube orally.
We have used this technique in five patients. Four were ASA physical status I or II adult patients presenting for molar extraction in whom the FLMA was easily inserted under general anesthesia. The fifth patient was a mentally retarded adult presenting for dental clearance who had micrognathia and was a Mallampati Grade 4. It was felt that nasal intubation was essential for surgery. The patient was therefore sedated with thiopentone 2 mg/kg, and the FLMA was placed while the patient breathed spontaneously. Anesthesia was induced with isoflurane once the airway was secure. The time taken to convert from the oral to nasal airway was 20-70 s, and there were no problems with airway management during the 30- to 190-min procedures. Returning the FLMA tube to the oral cavity at the end of the procedure took 10-40 s. The bowl of the FLMA was not displaced from the pharynx during the exchange maneuvers. One patient had a minor epistaxis, but there were no other problems.
The potential advantages of the technique are that it allows perfect access to the oral cavity without the need for tracheal intubation. Initial experience suggests that the technique is simple, atraumatic, applicable to the normal and difficult airway. We would consider this technique only suitable for practitioners who are highly experienced with the FLMA.
L. Marchionni, MD
F. Agro, MD
R. Favaro, MD
Department of Anaesthesia; Policlinico Universitario; Roma, Italy
C. Verghese, FRCA
Department of Anaesthesia and Intensive Care; Royal Berkshire Hospital; Reading, UK
J. Brimacombe, MD, FRCA
Department of Anaesthesia and Intensive Care; University of Queensland; Cairns, Australia
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