To the Editor:-We read the article by Cros et al. [1] regarding the case reports of recurrent laryngeal nerve palsy and arytenoid dislocation after the use of a laryngeal mask airway (LMA), and would like to make the following observations. The authors state that in cases 1 and 2, a misplacement of the LMA could be excluded because there was no obstruction to the breathing and because it appeared to be positioned correctly. However, it has been shown that even a malpositioned mask may function well and appear to be positioned correctly, [2] but the cuff may not occupy its intended position when verified by fiberscopy. [3]
It is not clear whether the authors used the standard technique of insertion [4] or any other alternate technique. The current evidence suggests that the use of the standard technique, which is based on the physiologic principle of swallowing, reduces the incidence of malpositioning. [5] However, the standard insertion technique is not easy to master, and there is a long learning curve. [6] Moreover, even with a nonstandard technique, a satisfactory airway can usually be achieved. This encourages beginners to adopt a complacent attitude toward practicing the standard technique, such a tendency should be discouraged. During the insertion of an LMA, close attention to detail is necessary, e.g., during cuff inflation the mask should not be held down but allowed to take up the final position freely and only after this step the tube should be fixed facing caudally. [4] Holding the mask down at the time of cuff inflation may lead to transmission of excessive pressure on the surrounding mucosa by allowing the mask to be fixed in an inappropriate position.
In case 2, the LMA was lubricated with silicone spray. Silicone based lubricants are contraindicated for use with an LMA as they degrade the material and alter the dimensions of the cuff. [4] A significant change in cuff compliance and shape could exert uneven pressure on the surrounding mucosa, leading to the complication described in this patient.
The LMA is a very user-friendly and safe device; severe morbidity after the use of an LMA is rare and may further be reduced by meticulous preparation and the adoption of the standard technique.
Pramod P. Bapat, M.D., F.R.C.A.
Department of Anesthetics
Charing Cross Hospital
Fulham Palace Road
London W6 8RF
United Kingdom
Chandy Verghese, F.R.C.A.
Department of Anesthetics
Royal Berkshire Hospital
Reading RG1 5AN
United Kingdom
