Bennett J A, Abrams J T, Van Riper D F, Horrow J C
Department of Anesthesiology, Hahnemann Division, Allegheny University of the Health Sciences, Philadelphia, Pennsylvania 19102-1192, USA.
Anesthesiology. 1997 Nov;87(5):1070-4. doi: 10.1097/00000542-199711000-00010.
Opioid-induced rigidity often makes bag-mask ventilation difficult or impossible during induction of anesthesia. Difficult ventilation may result from chest wall rigidity, upper airway closure, or both. This study further defines the contribution of vocal cord closure to this phenomenon.
With institutional review board approval, 30 patients undergoing elective cardiac surgery participated in the study. Morphine (0.1 mg/kg) and scopolamine (6 microg/kg) given intramuscularly provided sedation along with intravenous midazolam as needed. Lidocaine 10% spray provided topical anesthesia of the oropharynx. A fiberoptic bronchoscope positioned in the airway photographed the glottis before induction of anesthesia A second photograph was obtained after induction with 3 microg/kg sufentanil administered during a period of 2 min. A mechanical ventilator provided 10 ml/kg breaths at 10/min via mask and oral airway with jaw thrust. A side-stream spirometer captured objective pulmonary compliance data. Subjective airway compliance was scored. Pancuronium (0.1 mg/kg) provided muscle relaxation. One minute after the muscle relaxant was given, a third photograph was taken and compliance measurements and scores were repeated. Photographs were scored in a random, blinded manner by one investigator. Wilcoxon signed rank tests compared groups, with Bonferroni correction. Differences were considered significant at P < 0.05.
Twenty-eight of 30 patients exhibited decreased pulmonary compliance and closed vocal cords after opioid induction. Two patients with neither objective nor subjective changes in pulmonary compliance had open vocal cords after opioid administration. Both subjective and objective compliances increased from severely compromised values after narcotic-induced anesthesia to normal values (P = 0.000002) after patients received a relaxant. Photo scores document open cords before induction, progressing to closed cords after the opioid (P = 0.00002), and opening again after a relaxant was administered (P = 0.00005).
Closure of vocal cords is the major cause of difficult ventilation after opioid-induced anesthesia.
阿片类药物诱发的强直常常使麻醉诱导期间的面罩通气困难或无法进行。通气困难可能源于胸壁强直、上气道关闭或两者皆有。本研究进一步明确了声带关闭对此现象的影响。
经机构审查委员会批准，30例择期心脏手术患者参与了本研究。肌肉注射吗啡（0.1mg/kg）和东莨菪碱（6μg/kg）进行镇静，并根据需要静脉注射咪达唑仑。10%利多卡因喷雾用于口咽局部麻醉。在麻醉诱导前，将纤维支气管镜置于气道内拍摄声门。在2分钟内静脉注射3μg/kg舒芬太尼诱导后拍摄第二张照片。通过面罩和口咽气道并采用下颌前推，用机械通气机以10ml/kg的潮气量、10次/分钟的频率进行通气。旁流式肺量计记录客观的肺顺应性数据。对主观气道顺应性进行评分。泮库溴铵（0.1mg/kg）用于肌肉松弛。给予肌肉松弛剂1分钟后，拍摄第三张照片，并重复进行顺应性测量和评分。由一名研究人员以随机、盲法方式对照片进行评分。采用Wilcoxon符号秩检验进行组间比较，并进行Bonferroni校正。P<0.05时差异具有统计学意义。
30例患者中有28例在阿片类药物诱导后出现肺顺应性降低和声门关闭。2例肺顺应性在客观和主观上均无变化的患者在给予阿片类药物后声门开放。在患者接受肌肉松弛剂后，主观和客观顺应性均从麻醉诱导后的严重受损值增加至正常水平（P=0.000002）。照片评分显示诱导前声门开放，阿片类药物给药后声门关闭（P=0.00002），给予肌肉松弛剂后声门再次开放（P=0.00005）。
声带关闭是阿片类药物诱导麻醉后通气困难的主要原因。
