Postoperative laryngeal competence. The laryngeal mask airway and tracheal tube compared.

We investigated the incidence of postoperative laryngeal incompetence in 40 patients undergoing lower limb arthroplasty. Patients were randomly allocated to one of two groups using a standardised general anaesthetic/muscle relaxant technique; in group A the patients' lungs were ventilated via a laryngeal mask airway and in group B via a tracheal tube. Following recovery from general anaesthesia, at a time when patients were considered safe for discharge back to the general ward, they were asked to swallow 20 ml of barium, and an immediate portable chest X ray was taken. The X rays were examined for evidence of tracheopulmonary aspiration. Contrary to previous studies the incidence of aspiration was low, occurring in only one patient. This aspiration was, however, clinically silent. The exact mechanism of this apparent laryngeal incompetence, which occurred in a patient from the tracheal tube group, is unclear. Due to the relatively small numbers of patients studied no conclusions can be drawn about the relative benefits of the use of the laryngeal mask airway with regard to postoperative laryngeal competence.