[Use of the laryngeal mask in difficult intubation]

Although the incidence of difficult airway is very low, involving less than 1% of all patients, failed air-way management is the main cause of mortality or serious morbidity during anaesthesia. Successful management of a difficult airway starts with recognition of the potential problem. A careful preoperative history and clinical examination should elicit obvious problems to allow prediction of a potentially difficult airway. Besides the introduction of different instruments and techniques, the laryngeal mask (LMA) has been suggested to be effective both in when difficult airway is known in advance to be present and after failed intubation. CASE REPORT. The use of the LMA in a patient scheduled for endoscopic resection of a ureteral stone as day surgery is described. The patient presented reduced mobility of the atlanto-occipital joint, temporomandibular ankylosis (mouth opening of 1.9 cm), dislocated teeth, and kyphosis of the thoracic spine. Due to deformation of the spine, the patient was placed in a half-sitting position (30 degrees). Anaesthesia was induced with fentanyl (1.5 micrograms.kg-1) and propofol (2 mg.kg-1). Although the conditions made it difficult to manage the patient's airway, the LMA was inserted without complications or trauma. Anaesthesia was maintained with isoflurane and nitrous oxide in oxygen. After 1.5 h of assisted ventilation the LMA was removed when the patient opened his mouth on request. DISCUSSION. Significant advances in the management of the difficult airway have been achieved in recent years. However, avoidable deaths on intubation have been attributed to unexpected difficulties and poorly managed situations. Thus every anaesthetist should be prepared for potential difficulties by training and be able to follow a rational plan of action. If despite all manoeuvres a tracheal tube cannot be passed, a failed intubation drill must be instituted, and if oxygenation is still not possible a failed ventilation drill must be followed. The LMA is a new device developed to provide an airway for anaesthesia. However, since the LMA can be inserted quickly and blind, it can be used as an alternative airway in patients in whom the trachea is difficult to intubate. The lower incidence of post-operative complications than with endotracheal intubation is a further advantage, particularly during anaesthesia for day surgery.