Adolphs Jörn, Schmidt Diego K, Mousa Shaaban A, Kamin Britta, Korsukewitz Ines, Habazettl Helmut, Schäfer Michael, Welte Martin
Department of Anesthesiology and Intensive Care Medicine, Freie Universität Berlin, Germany.
Anesthesiology. 2003 Sep;99(3):685-92. doi: 10.1097/00000542-200309000-00025.
During hemorrhagic hypotension, sympathetic vasoconstriction crucially contributes to gut mucosal damage. Sympathetic blockade by thoracic epidural anesthesia has been shown to increase mucosal microvascular perfusion and to improve survival after severe hemorrhage in laboratory animals. This study investigates the effects of thoracic epidural anesthesia on intestinal microvascular perfusion during hemorrhagic hypotension in rats.
In 32 anesthetized Sprague-Dawley rats either lidocaine 2% (thoracic epidural anesthesia) or normal saline (control) was infused via thoracic epidural catheters. Hemorrhagic hypotension (mean arterial pressure 30 mmHg for 60 min) was induced by withdrawal of blood, which was subsequently retransfused for resuscitation. Functional capillary density and erythrocyte velocity in the mucosa and muscularis were determined by intravital microscopy. Leukocyte-endothelium interaction was studied in postcapillary venules and sympathetic nerve fibers of the intestinal wall were identified by immunohistochemistry.
During hypotension functional capillary density was significantly (P < 0.001) lower in the muscularis of the control group (median [25/75 percentile]: -46.5% [-59.6/-20.8%] change from baseline) as compared with animals that received thoracic epidural anesthesia (-6.1% [-13.4/1.1%]). There were no differences in erythrocyte velocity between groups throughout the experiment. Leukocyte rolling increased significantly (P < 0.001) after resuscitation in control (12 [6/15] vs. baseline 2.5 [1/8]) but not in thoracic epidural anesthesia (4 [2.3/7] vs. baseline: 5 [3/15.5]). Sympathetic nerve fibers were identified in the muscularis and submucosa but not in the mucosa.
During hemorrhagic hypotension and after resuscitation, thoracic epidural anesthesia has beneficial effects on intestinal microvascular perfusion. Because of blockade of sympathetic nerves, thoracic epidural anesthesia prevents perfusion impairment of the muscularis during hypotension and attenuates leukocyte rolling after resuscitation.
在失血性低血压期间，交感神经血管收缩是导致肠黏膜损伤的关键因素。在实验动物中，胸段硬膜外麻醉引起的交感神经阻滞已被证明可增加黏膜微血管灌注并提高严重出血后的生存率。本研究旨在探讨胸段硬膜外麻醉对大鼠失血性低血压期间肠道微血管灌注的影响。
对32只麻醉的Sprague-Dawley大鼠，通过胸段硬膜外导管输注2%利多卡因（胸段硬膜外麻醉）或生理盐水（对照组）。通过放血诱导失血性低血压（平均动脉压30 mmHg，持续60分钟），随后回输血液进行复苏。通过活体显微镜测定黏膜和肌层的功能性毛细血管密度和红细胞速度。在毛细血管后微静脉中研究白细胞与内皮细胞的相互作用，并通过免疫组织化学鉴定肠壁的交感神经纤维。
在低血压期间，对照组肌层的功能性毛细血管密度显著低于接受胸段硬膜外麻醉的动物（中位数[第25/75百分位数]：与基线相比变化为-46.5%[-59.6/-20.8%]，P<0.001）（-6.1%[-13.4/1.1%]）。在整个实验过程中，两组之间的红细胞速度没有差异。复苏后，对照组白细胞滚动显著增加（P<0.001）（12[6/15]对比基线2.5[1/8]），而胸段硬膜外麻醉组则没有（4[2.3/7]对比基线：5[3/15.5]）。在肌层和黏膜下层发现了交感神经纤维，但在黏膜中未发现。
在失血性低血压期间及复苏后，胸段硬膜外麻醉对肠道微血管灌注具有有益作用。由于交感神经被阻滞，胸段硬膜外麻醉可防止低血压期间肌层的灌注受损，并减轻复苏后白细胞的滚动。
