[The importance of the laryngeal mask in the difficult intubation and early experience with the intubating laryngeal mask airway--ILMA--Fastrach].

UNLABELLED: The conventional laryngeal mask airway ("Standard" laryngeal mask airway SLMA is of outstanding importance in the management of the difficult airway. The intubating laryngeal mask airway (ILMA, commercial name Fastrach) has become available recently. First results indicate that the excellent ventilation characteristics of SLMA are maintained, but in addition blind intubation is successful in more than 90% of patients with normal anatomy as well as with difficult intubation.

PURPOSE: We present the use of ILMA, compare the potential of the two laryngeal mask types in difficult intubation by own results, present the results of a first symposium on the ILMA held at Jersey in December 1996, the role of the SLMA in difficult intubation as proposed by the American and the French Societies of Anaesthesiology, as well as an outlook on possible uses of the ILMA in the light of the available results.

METHODS: The SLMA was prospectively used between 1992 and 1997 for 66 operations in 55 patients with difficult intubation (laryngoscopic view Cormack grade IV, n = 24; grade III, n = 35; grade < III, n = 7). 48 operations were performed after resection of a facial carcinoma, 14 on patients without carcinoma who could not be intubated conventionally, 5 on patients with periglottic pathology, and on 50 normals. The ILMA was used on 150 patients between 11/1996 and 11/1997, 106 had normal anatomy, 33 were difficult to intubate (Cormack grade IV, n = 12; grade III, n = 21), 24 had a reduced mouth opening of < or = 2.5 cm awake, 14 of these also were difficult to intubate.

RESULTS: Ventilation was superior to a face mask (FM): (SLMA: ventilation not sufficient (SaO2 < 90% > 30 sec) with a FM in 22 operations compared to 5 with a SLMA; ILMA: ventilation not sufficient with a FM in 7 operations compared to 3 with an ILMA). Blind intubation through a SLMA had a success rate of 50% and 34% in 50 normals and in 32 operations with difficult intubation after a mean of 2.6 intubation attempts each. The success rate per intubation attempt for the SLMA was 22% in normals and 13% in difficult intubation. Through an ILMA, blind intubation was successful in 92% of normals, 5 of them with immobile spine, in 91% in patients with difficult intubation, and in 83% in patients with reduced mouth opening. The success rate per intubation attempt was 60% in normals, 46% in difficult intubation, and 46% in reduced mouth opening, with a success rate for the first intubation attempt of 57%. This compares favourably with results presented at the Jersey symposium in 554 patients.

CONCLUSION: The ILMA maintains the superb ventilation potential of a SLMA in difficult intubation but doubles the success rate of blind intubation irrespective of anatomical difficulties, with a 50% success rate during the first intubation attempt. Possible uses of the ILMA may be in difficult intubation situations including immobile spine, in cannot ventilate--cannot intubate situations comparable to a SLMA with an improved chance of successful intubation, and perhaps as a device for ventilation and intubation for untrained people. The use of the ILMA can be trained during everyday practice. Expert assessment of successful endotracheal tube position is mandatory.