EDITOR:
Hypoglossal nerve injury has been reported as a complication associated with airway management using supraglottic airways [Reference Nagai, Sakuramoto and Goto1–Reference Trumpelmann and Cook5]. The CobraPLA™ (CPLA) is a relatively new supraglottic airway device. There is no report of cranial nerve injury following the use of the CPLA. We present a case of hypoglossal nerve injury after the use of the CPLA.
A healthy 51-yr-old male, height 177 cm, weight 80 kg, was scheduled for elective orthopaedic surgery for ulnar nerve palsy after right supracondylar fracture. He had no past medical history. His preanaesthetic physical examination was normal. Midazolam 3.0 mg and glycopyrrolate 0.2 mg was given intravenously for premedication. Anaesthesia was induced with propofol 100 mg and rocuronium 50 mg. A CPLA, size 4, was inserted successfully on the first attempt without difficulty. The cuff was inflated with air by using a manometer (Cuff Pressure Gauge; VBM Medizintechnik, Sulz, Germany) to a pressure of 60 cm H2O. Anaesthesia was maintained with enflurane, air and oxygen. We monitored cuff pressure continuously and kept the pressure between 60 and 70 cm H2O throughout the operation. The patient’s head was placed in the neutral position during the operation. The operation was uneventful and lasted 2 h 55 min. After the patient was awakened, the CPLA cuff was deflated and expelled. There was no blood on the surface of the cuff. After discharge from the recovery room, the patient complained of a strange feeling in his tongue and some impairment of speech. On the day after the operation, his tongue deviated to the right on protrusion. Swelling was observed on the right side of the tongue. Neurological examination was otherwise normal. Diagnosis of an isolated right hypoglossal nerve injury was made. Dexamethasone 10 mg was given followed by prednisolone 60 mg day−1. After 7 days, deviation of the tongue was much improved. After 12 days, he was discharged with only a slight deviation remaining. He was scheduled for outpatient follow-up.
The use of supraglottic airway is increasing and with it the number of complications. Supraglottic airways are relatively atraumatic, but any manipulation of the oropharyngeal cavity might lead to injury of any related structure contained therein. Hypoglossal nerve injury is a rare complication of airway manipulation using a supraglottic airway. It may be injured, alone or in combination with the lingual nerve and/or recurrent laryngeal nerve. Many cases are related to the use of N2O, the position of the patient during the operation or the preexisting disease [Reference Nagai, Sakuramoto and Goto1–Reference Trumpelmann and Cook5]. Excessive cuff pressure or malposition of cuff is likely to have played a part. In this case, we did not use N2O, and monitored and kept the cuff pressure below 70 cm H2O continuously. The head was placed neutrally without fixation. The position of the CPLA had no problem clinically, but we cannot rule out the possibility of an improper position of the tongue. Also, we think that the operation time was relatively long. Even when a patient is healthy, N2O is not used, and the patient is placed neutrally; prolongation of the operation might increase the risk of nerve injury in patients using the CPLA.
