Glottic Closure Reflex in an Anesthetized and Awake Canine Model

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J Korean Soc Laryngol Phoniatr Logop > Volume 14(2); 2003 > Article

Journal of The Korean Society of Laryngology, Phoniatrics and Logopedics 2003;14(2): 83-87.

개의 성문폐쇄반사에 미치는 중추조절의 영향에 관한 연구

강주완, 김광문, 김영호

연세대학교 의과대학 이비인후과학교실, 음성언어의학연구소

Glottic Closure Reflex in an Anesthetized and Awake Canine Model

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ABSTRACT

Background and Objectives
: Sphincteric function of the larynx, essential to lower airway protection, is most efficiently achieved through strong reflex adduction by both vocal cords. We hypothesize that central facilitation is an essential component of a bilateral adductor reflex and that its disturbance could result in weakened sphincteric closure.
Materials and Method
: Seven adult 20kg dogs underwent evoked response laryngeal electromyoraphy under 0.5 to 1.0 MAC isoflurane anesthesia. The internal branch of superior laryngeal nerve was stimulated through bipolar platinum-iridium electrodes and recording electrodes were positioned in the ipsilateral and contralateral thyroaryteonoid muscles.
Results
: Consistent threshold responses were obtained ipsilaterally under all anesthetic levels. However, contralateral reflex responses disappeared as anesthetic levels approached 1.0 MAC. Additionally, at 0.5 MAC, late responses (R2) were detected in one animal.
Conclusion
: Alteration of central facilitation by deepening anesthesia abolishes the crossed adductor reflex, predisposing to a weakened glottic closure response. Precise understanding of this effect may improve the prevention of aspiration in patients emerging from prolonged sedation or under heavy psychotropic control.

KEY WORDS： Glottic closure reflex;Anesthesia;

중심 단어： 성문폐쇄반사;마취;