Anesth Analg 1999;89:1066
© 1999 International Anesthesia Research Society
LETTERS TO THE EDITOR
Respiratory Complications Associated with Tracheal Extubation in Adults
Takashi Asai, MD, PhD
Department of Anesthesiology Kansai Medical University Moriguchi City, Osaka, Japan
I read with interest the article of Webster et al. (1) who compared the efficacy of the flexible reinforced laryngeal mask with a tracheal tube during intranasal surgery. They also compared the incidence of complications associated with removal of the laryngeal mask, tracheal extubation when the patient was deeply anesthetized with tracheal extubation when the patient had regained consciousness.
They claim that "[e]valuation of tracheal extubation in awake and anesthetized patients has been examined in children but not in adults" (1). However, we studied this factor in adults, and the study was published (2,3) well before the date of acceptance of Webster et al.’s article (1).
Webster et al. (1) report that coughing occurred in 19 of 32 patients (59%) when the trachea was extubated during deep anesthesia, defined as "at a depth of anesthesia [after cessation of inhalational anesthetics] sufficient to suppress the cough reflex response to movement to the lateral position and cuff deflation." I suggest that if the trachea is extubated before isoflurane is turned off, the incidence of coughing could be minimized, although supporting the jaw may often be required to maintain a patent airway (2).
References
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Webster AC, Morley-Forster PK, Janzen V, et al. Anesthesia for intranasal surgery: a comparison between tracheal intubation and the flexible reinforced laryngeal mask airway. Anesth Analg 1999;88:421–5.[Abstract/Free Full Text]
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Koga K, Asai T, Vaughan RS, Latto IP. Respiratory complications associated with tracheal extubation: timing of tracheal extubation and use of the laryngeal mask during emergence from anaesthesia. Anaesthesia 1998;53:540–4.[Web of Science][Medline]
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Asai T, Koga K, Vaughan RS. Respiratory complications associated with tracheal intubation and extubation. Br J Anaesth 1998;80:767–75.[Abstract/Free Full Text]
Response
Pat Morley-Forster, MD, FRCPC,
James Watson, MD, FRCPC,
Victor Janzen, MD, FRCPC,
Anthony Webster, MB, FRCPC, and
Steve Dain, MD, FRCPC
St. Joseph’s Health Center, University of Western Ontario, London, Ontario, Canada
We appreciate the interest shown by Dr. Asai in our article describing the use of the flexible reinforced laryngeal mask airway for intranasal surgery. Our study was originally submitted to Anesthesia & Analgesia in May, 1998, just before the two articles on the topic of tracheal extubation in adults by Dr. Asai et al. were published. Our article required revision, was resubmitted in September, 1998, and was accepted for publication in November, 1998. Dr. Asai’s articles were published in June, 1998 while we were revising the manuscript. The findings of Dr. Asai et al. support the conclusion of our paper, i.e., the use of the laryngeal mask compared with endotracheal intubation decreases the incidence of respiratory complications on emergence.
Dr. Asai suggests that coughing could be minimized by extubating the trachea before the isoflurane is discontinued. In fact, this was the method we followed in Group III, the patients were extubated while they were deeply anesthetized. The wording is somewhat misleading and should be clarified. As stated in the article, the isoflurane was discontinued in all groups after lateral positioning. However, Group III patients were extubated immediately after lateral positioning, while isoflurane was still being administered. If they coughed in response to being turned, the isoflurane concentration was increased until they were breathing regularly. After deep extubation, the inhaled anesthetic was discontinued, and these patients breathed air/oxygen while a patent airway was maintained by jaw thrust. The coughing that occurred in 59% of Group III patients as they emerged from the anesthetic was probably attributable to blood trickling onto their vocal cords.
We hope these explanations clarify the points raised by Dr. Asai et al.
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