To the Editor:—
I was interested to read the article by Gaitini et al. 1There are many products similar to the Combitube (Tyco-Kendall-Sheridan, Mansfield, MA) that have been designed to maintain a patent airway in anesthetized or unconscious patients. One such product (fig. 1), called the Airway Management Device (AMD; Nagor Limited, Isle of Man, British Isles) has been marketed recently in the United Kingdom.
The common features of these devices include one oropharyngeal cuff and one esophageal cuff. We encountered problems with these inflated cuffs while conducting our audit on the AMD™ during general anesthesia.
We noticed that the inflated oropharyngeal cuff was causing congestion, protrusion, and bluish discoloration of the tongue. These problems were noted even with an oropharyngeal cuff pressure of less than 15 cm H2O. None of our patients experienced any damage. However, a congested and swollen tongue is a potential cause of airway obstruction after extubation. Long-term congestion may result in ischemic injury to the tongue. Concern has also been expressed about the possibility of lingual nerve damage and venous thrombosis due to high intracuff pressure. 2Gaitini et al. 1overinflated the oropharyngeal cuff with an additional 15–20 ml air. A very high intracuff pressure could have developed with overinflation. Even an underinflated cuff with half of the recommended volume of air recorded a pressure of 110 cm H2O. 3A high intracuff pressure could seri-ously compromise the circulation of the tongue, especially in association with hypotension. It has been recommended to monitor the intracuff pressure, but the safe level of pressure has not been well-defined. 3
An inflated cuff placed in the upper end of the esophagus should adequately provide airway protection against gastric regurgitation. 4However, this may not happen in practice. An inflated upper esophageal cuff could prevent regurgitation by mechanical obstruction, but it could make the upper esophageal sphincter incompetent. In our audit, we found unexpected regurgitation in two patients. Fortunately, none of them had signs or symptoms of aspiration. These unexpected incidents may be due to incompetent esophageal sphincter caused by the inflated cuff. In their study, Urtubia et al. 4also noted an unexpected case of regurgitation. Thus, these devices could be useful in difficult airway situations. 3However, because of those potential problems, they should be used with caution until more studies are available to prove their safety especially for long-term use. Also, a clear guideline in relation to the safe level of intracuff pressure should be in place.