Characteristics of Glottic Closure Reflex in a Canine Model
Characteristics of Glottic Closure Reflex in a Canine Model
复制标题
犬模型中声门关闭反射的特征
作者：
Young‐Ho Kim;J. Kang;Kwang
目的喉的最重要功能是保护气道，这是通过声门和声门上粘膜中的受体触发的多突触反射关闭来提供的，特别是通过声带的强烈内收引起喉肌的反射性收缩。基于中枢易化对这种双侧内收肌反射至关重要，并且其干扰可导致喉关闭减弱的假设，我们设计了这项研究来阐明中枢易化对这种保护性反射的影响。材料与方法7只成年杂种犬，20 kg，在0.5 ~ 1.0 MAC（最小肺泡浓度）异氟醚麻醉下进行诱发反应喉肌电图检查。采用双极铂铱电极刺激上级喉上神经内分支，记录电极分别置于同侧和对侧甲杓肌。结果无论麻醉平面如何，同侧反射闭合均能持续记录。然而，随着麻醉水平的加深，对侧反射反应消失。此外，在较低麻醉水平的一只动物中检测到迟发反应（R2）。结论麻醉平面加深会影响中枢易化作用，导致交叉内收肌反射消失，声门闭合反应减弱。对这种效应的准确理解可能会提供一种方法来防止无意识患者的误吸。
Purpose The most important function of the larynx is airway protection which is provided through a polysynaptic reflex closure triggered by the receptors in the glottic and supraglottic mucosa, evoking the reflex contraction of the laryngeal muscles especially by strong adduction of vocal cords. Based on the hypotheses that central facilitation is essential for this bilateral adductor reflex and that its disturbance can result in weakened laryngeal closure, we designed this study to elucidate the effect of central facilitation on this protective reflex. Materials and Methods Seven adult, 20 kg mongrel dogs underwent evoked response laryngeal electromyography under 0.5 to 1.0 MAC (minimum alveolar concentration) isoflurane anesthesia. The internal branch of the superior laryngeal nerve was stimulated through bipolar platinum-iridium electrodes, and recording electrodes were positioned in the ipsilateral and contralateral thyroarytenoid muscles. Results Ipsilateral reflex closure was consistantly recorded regardless of anesthetic levels. However, contralateral reflex responses disappeared as anesthetic levels were deepened. Additionally, late responses (R2) were detected in one animal at lower level of anesthesia. Conclusions Deepened level of anesthesia affects central facilitation and results in the loss of the crossed adductor reflex, predisposing to a weakened glottic closure response. Precise understanding of this effect may possibly provide a way to prevent aspiration in unconscious patients.