Direct in vivo visualization of bronchodilation induced by inhalational anesthesia using high-resolution computed tomography.
Direct in vivo visualization of bronchodilation induced by inhalational anesthesia using high-resolution computed tomography.
复制标题
使用高分辨率计算机断层扫描直接体内观察吸入麻醉引起的支气管扩张。
DOI：
10.1097/00000542-199302000-00013
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发表时间：
1993
期刊：
影响因子：
8.8
通讯作者：
Hirshman,CA
中科院分区：
文献类型：
--
作者：
Brown,RH;Mitzner,W;Zerhouni,E;Hirshman,CA
背景挥发性麻醉药在预防和逆转支气管痉挛方面是有效的，但其对基线气道张力的影响存在争议。虽然钽支气管造影术过去已用于测量一维气道直径变化，但该方法存在与钽刺激性效应相关的固有问题。直到最近，没有其他直接的非侵入性体内方法来评估气道口径。本调查评估的影响，吸入麻醉剂氟烷对个人未受刺激的airways in vivo.MethodsTen研究进行了7只狗。所有狗最初用15 mg/kg硫喷妥钠麻醉，随后用10 mg硫喷妥钠麻醉。kg-1 x h-1维持剂量。气管插管后，对肺部进行机械通气（15 ml/kg，15次/min）。随后，犬接受递增剂量的氟烷（范围0.5-1.5%）。在另一天，用阿托品（0.2 mg/kg）对犬进行预处理，并重复研究。使用1 s扫描时间、137 kVp、220 mA、2 mm层厚和1 mm工作台进给获得50次连续高分辨率计算机断层扫描。结果0.5%、1.0%和1.5%浓度的氟烷均能明显扩张气道，且呈剂量依赖性（相对于对照的百分比增加），平均值分别为90+/-19%（平均值+/-SEM）、128+/-20%和182+/-27%（P=. 017）。单独阿托品预处理显著扩张气道至151+/-25%（P=. 002)的基线值。氟烷在阿托品预处理dogs.ConclusionsHalothane没有引起进一步的气道扩张基线气道通过阻断基线迷走神经张力。由于基线气道张力、气道壁厚度和初始气道直径是气道反应性的主要决定因素，因此观察到的氟烷扩张可能是吸入麻醉剂降低气道反应性的机制之一。
BackgroundVolatile anesthetics are effective at preventing and reversing bronchospasm, but their effects on baseline airway tone are controversial. While tantalum bronchography has been used in the past to measure one-dimensional airway diameter changes, this method has inherent problems associated with the irritant effects of tantalum. Until recently, no other direct noninvasive in vivo method to assess airway caliber was available. The present investigation assesses the effects of the inhalation anesthetic halothane on individual unstimulated airways in vivo.MethodsTen studies were performed in seven dogs. All dogs were initially anesthetized with 15 mg/kg thiopental followed by a 10-mg. kg-1 x h-1 maintenance dose. Following tracheal intubation the lungs were mechanically ventilated (15 ml/kg, 15 beats/min). The dogs subsequently received increasing doses of halothane (range 0.5-1.5%). On a separate day, the dogs were pretreated with atropine (0.2 mg/kg) and the study was repeated. Fifty sequential high-resolution computed tomography scans were obtained using a 1-s scan time, 137 kVp, 220 mA, 2-mm slice thickness, and 1-mm table feed. Airway areas ranging in size from 3 to 22 mm in diameter were measured and analyzed by one way analysis of variance and Bonferroni pair-wise comparisons of means.ResultsHalothane in concentrations of 0.5%, 1.0%, and 1.5% showed significant dose-dependent dilation of the airways (percent increase from control) that averaged 90+/-19%(mean+/-SEM), 128+/-20%, and 182+/-27%, respectively (P=. 017). Atropine pretreatment alone significantly dilated the airways to 151+/-25%(P=. 002) of their baseline value. Halothane caused no further airway dilation in atropine pretreated dogs.ConclusionsHalothane dilates baseline airways by blocking baseline vagal tone. Since baseline airway tone, airway wall thickness, and initial airway diameter are major determinants of airway reactivity, the observed dilation by halothane may be one of the mechanisms by which inhalational anesthetics decrease airway reactivity.