To the Editor:
Chia et al., comparing induction of anesthesia using propofol or thiopental on the incidence and severity of pharyngeal morbidity in patients in whom an LMA was used,1 allowed intracuff pressure of up to 100 cm H2O. Brimacombe et al. showed that the posterior pharyngeal mucosal perfusion pressure was progressively reduced when mucosal pressure was increased from 34 to 80 cm H2O,2 but higher cuff volume might cause more mucosal pressure only at some locations.3 Thus, high intracuff pressure as a cause of pharyngeal morbidity should be excluded before attributing it to the use of thiopental. As the maximum recommended intracuff pressure is 60 cm H2O, I suggest that the author could have compared the incidence of pharyngeal morbidity in patients with low cuff pressure (<60 cm H2O) and high cuff pressure (>60 cm H2O) separately. Also, the authors did not mention the use of nitrous oxide, which might increase the intracuff pressure.
Chitra Rajeswari Thangaswamy
Department of Anaesthesiology and Intensive Care
All India Institute of Medical Sciences
Ansari Nagar
New Delhi, India 110029
[email protected]
REFERENCES
1. Chia YY, Lee SW, Liu K. Propofol causes less postoperative pharyngeal morbidity than thiopental after the use of a laryngeal mask airway. Anesth Analg 2008;106:123–6
2. Brimacombe J, Keller C, PĂ¼hringer F. Pharyngeal mucosal pressure and perfusion: a fiberoptic evaluation of the posterior pharynx in anesthetized adult patients with a modified cuffed oropharyngeal airway. Anesthesiology 1999;91:1661–5
3. Brimacombe J, Keller C. A comparison of pharyngeal mucosal pressure and airway sealing pressure with the laryngeal mask airway in anesthetized adult patients. Anesth Analg 1998;87:1379–82
Section Description
Editor's note:Due to a publisher's error, the following response by Amar et al. to the Letter to the Editor by Lohser and Brodsky published in the July 2008 issue (Anesth Analg 2008;107:342) was left out of the July issue. The publisher apologizes for the error.
