[Sudden vocal cord closure during general anesthesia using remifentanil].

We experienced three cases of ventilatory difficulty through a Proseal laryngeal mask airway was encountered during general anesthesia using remifentanil and sevoflurane. General anesthesia was induced with propofol and maintained with remifentanil (0.2-0.25 microg x kg(-1) x min(-1)) and sevoflurane (1-1.5%). Increased airway pressure was noticed suddenly. Initially in cases 1 and 2, we suspected insufficient depth of anesthesia as a cause of this event. However, in case 3, we observed vocal cord closure by fiberoptic bronchoscopy, suggesting that airway obstruction occurred at the level of the glottis. The patient could be easily ventilated after administration of muscle relaxant (suxamethonium). The inability to ventilate patients with opioids has been ascribed to increased thoracic wall rigidity or vocal cord closure or combination of both factors. In our three cases, the closure of vocal cord after remifentanil administration seems to be the major cause of difficult ventilation during general anesthesia. Therefore, supraglottic airway devices should be applied with caution during general anesthesia with remifentanil and sevoflurane without muscle relaxant.