[A case of ventilatory difficulty during the use of the laryngeal mask airway]

A 67-year-old male patient with chronic tympanitis was scheduled for elective tympanoplasty. Propofol and fentanyl were used for induction and the patient was ventilated with sevoflurane, oxygen and nitrous oxide for general anesthesia. After about 10 minutes following anesthetic induction, the lungs suddenly could not be ventilated through the laryngeal mask airway, and then it was impossible to insert an endotracheal tube. The surgery was discontinued for the safety of the patient, in spite of the recovery of ventilation with a facemask. It is suspected that the ventilatory difficulty was caused by the following reasons; first, the laryngeal mask airway was shifted by change of the body position, second, the mask tip was inserted at the inlet of the larynx because the internal cuff pressure had risen with nitrous oxide.