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Department of Anesthesiology, Foothills Medical Center, Calgary, AB, Canada
To the Editor:
We read with interest the randomized clinical trial by Joo et al. (1) of difficult airway management, in which they compared the merits of inserting the intubating laryngeal mask airway (ILMA) under general anesthesia with awake fiberoptic intubation (AFOI).
Joo et al. (1) rightly point out that the ILMA can be used as the sole airway without tracheal intubation. Because a clear airway had been already obtained in patients in the ILMA group, it would be interesting to know why they required tracheal intubation. Having excluded patients at risk for aspiration of gastric contents, difficult ventilation, and supraglottic abnormalities, what indications, apart from the procedures, existed for tracheal intubation?
The supraglottic laryngeal mask airways (LMA-Classic (2,3), ILMA or Fastrach (4), and the LMA-ProSeal (5)) all permit positive pressure ventilation or spontaneous ventilation with minimal morbidity provided the appropriate size is used and the device is correctly placed. Even abdominal procedures, for which tracheal intubation was formerly considered mandatory, can be managed with supraglottic devices. The role of supraglottic airway devices for "nonconventional" uses is now acknowledged by reference texts within the specialty (6).
Joo et al.s study (1) challenges the "gold standard" of AFOI in a selected group of patients with previous or predicted difficult laryngoscopy. Perhaps the next "gold standard" to be challenged is whether every patient with a difficult airway requires endotracheal intubation. The advent of supraglottic airways, and the unique attributes of each, justifies subjecting airway strategies to randomized clinical trials (7). Thus procedures like AFOI, which require expensive equipment and consume valuable operating theater time and are "adamantly refused" by some patients, may have their indications better defined.
References
Department of Anesthesia, St. Michaels Hospital, Toronto, ON, Canada
In Response:
Drs. Beriault and Maltby raise a valid point that not all patients with difficult airways require tracheal intubation, especially with the advent of new airway devices that allow for better ventilation with minimal risk of aspiration of gastric contents. Clearly, for certain procedures, airway management without tracheal intubation is not only acceptable but also indicated. For this reason, we tested ventilation with the intubating laryngeal mask airway to determine its efficacy as a temporary ventilation device in patients with difficult airways. However, tracheal intubation is often required for surgical reasons. It was for this reason that tracheal intubation via the intubating laryngeal mask was performed on all patients.
The main purpose of our study (1) was to study the ILMA as a ventilation device and as an aid to tracheal intubation in patients with difficult airways. It was beyond the scope of the study to determine whether patients with difficult airways required tracheal intubation at all. I strongly agree that this is an area that needs further investigation. I would like to applaud Drs. Beriault and Malty for their efforts in challenging the status quo.
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