The intubating laryngeal mask. Results of a multicentre trial with experience of 500 cases

A multicentre trial of the use of the intubating laryngeal mask was carried out at seven centres in the United Kingdom using the same agreed protocol. Lung ventilation followed by blind tracheal intubation through the intubating laryngeal mask was attempted on 500 ASA grade 1 and 2 patients. It was possible to insert the intubating laryngeal mask in all 500 cases. Ventilation via the intubating laryngeal mask was described as satisfactory in 475 (95%) cases, difficult in 20 (4%) cases and unsatisfactory in 5 (1%) cases. Blind tracheal intubation through the intubating laryngeal mask was possible in 481 (96.2%) cases within three attempts. Intubation was successful at the first attempt in 399 (79.8%) cases, at the second attempt in 62 (12.4%) cases and at the third attempt in 20 (4%) cases. The tracheas of 19 (3.8%) patients were not successfully intubated within the three attempts. Ventilation via the intubating laryngeal mask was described as unsatisfactory during two of these cases but oxygenation remained satisfactory in spite of this. Seventeen of the 19 failures occurred during the individual operator's first 20 attempts. The intubating laryngeal mask provides a successful method for blind tracheal intubation in a large proportion of cases and appears to be superior to the standard laryngeal mask airway for this purpose. The intubating laryngeal mask may be of use when tracheal intubation has failed using conventional methods.