Salivary gland swelling and lingual nerve injury with the ProSeal laryngeal mask airway

Abstract

EDITOR: Lingual nerve palsy, parotid and submandibular gland swelling have been reported in association with the classic laryngeal mask airway (LMA) [1]. We report all three occurring in the same patient with the ProSeal LMA. A 64-yr-old female (height 158 cm, weight 76 kg, ASA I) was scheduled for day case hand surgery. She had no past medical history. Airway examination revealed Mallampati Grade 1 and good dentition. Induction was with midazolam 1.5 mg, alfentanil 0.5 mg and propofol 150 mg. Maintenance of anaesthesia was with sevoflurane 2-3% in oxygen 33% and air. A size 4 ProSeal LMA was easily inserted without any oropharyngeal resistance using the digital technique and the cuff inflated with 15 mL air. A water-based gel was used for lubricant. Most of the bite block was inside the mouth and the suprasternal notch tap test was positive, suggesting correct placement; however, ventilation was impossible despite a seal >50 cmH2O. An algorithm for the management of airway obstruction was followed: both jaw thrust and cuff deflation resulted in complete relief of airway obstruction, suggesting the aetiology was mechanical compression of the vocal cords or infolding of the cuff [2]. Subsequent fibreoptic inspection confirmed that the aetiology was cuff infolding which became clinically significant when the cuff volume exceeded 5 mL. A size 12-F gastric tube was easily inserted and 5 mL clear fluid aspirated from the stomach. The procedure, which was uneventful and lasted 45 min, was completed with the cuff inflated with only 2 mL of air and pressure controlled ventilation set at 16 cmH2O. Emergence was uneventful and the LMA was removed when the patient was able to open her mouth to command. There was no blood on the LMA or gastric tube. 2 h after the LMA was removed, the patient complained of difficulty speaking and swallowing, pain in the right side of her face, a lump in the floor of her mouth and a numb tongue. Examination revealed an enlarged non-tender right submandibular gland, an enlarged slightly tender right parotid gland and a right lingual nerve palsy. All other cranial nerves were intact and there was no evidence of tongue swelling or discolouration. There were no symptoms of sore throat or hoarseness. The patient was observed for 24 h, during which time all symptoms and signs disappeared, the parotid and submandibular gland swelling in 2-4 h and the lingual nerve palsy in 6-10 h. The lingual nerve and the parotid and submandibular ducts are vulnerable to compression and distortion within the oral/pharyngeal cavities. Malposition, cuff overinflation and undersizing have been the probably aetiology in previous reports [1]. The probable aetiology in the current case was that the ProSeal LMA was too big even when fully deflated. Perhaps it would be wise to downsize if full deflation of the cuff is required to relieve airway obstruction. Another reason to downsize is that the fully deflated cuff has a less effective seal for protection against regurgitation and gastric insufflation [3]. J. Brimacombe C. Keller *Department of Anaesthesia and Intensive Care, Cairns Base Hospital, James Cook University, Cairns, Australia †Department of Anaesthesia and Intensive Care Medicine, Medical University Innsbruck, Innsbruck, Austria