【作者】 刘少华；

【导师】 徐鑫荣；

【作者基本信息】 南京医科大学 ， 外科学， 2003， 硕士

【摘要】 感染性休克(Septic Shock)的病理生理特征是血管舒张、血压下降、心肌舒缩功能抑制、内脏灌注减少和多器官功能损害。监测技术和综合治疗手段的提高，未能降低高病死率，与它们未能阻断炎症介质连锁反应有关。NO是关键介质之一，阻断其作用，明显改善感染性休克血液动力学，但减少内脏器官血流灌注和氧合，损害多脏器功能。如何保留抑制NO后血液动力学益处，又不减少甚至增加内脏血流灌注和氧合，是临床医师需要解决的问题。NO通过激活可溶性鸟苷酸环化酶(sGC)舒张血管，降低血压。据研究内脏各器官血管床NO的生成和sGC的活化明显不同于体血管和心肌。因此抑制鸟苷酸环化酶可能改善感染性休克血液动力学且不影响内脏器官灌注和氧合，甚至随血压和脏器灌注压升高，内脏血流和氧合改善。MB是鸟苷酸环化酶选择性强抑制剂，因此我们进行了此研究。通过本研究观察MB对感染性休克血液动力学、内脏器官灌注和氧合、多器官功能的影响，探讨MB治疗感染性休克的可行性。 实验一：感染性休克犬动物模型的建立及评价 目的：探讨快速静脉泵入较大剂量内毒素建立感染性休克犬模型的可行性，并对模型进行评价。方法：12只健康杂种犬全麻和肌松后，内毒素250μg／kg于20分钟或500μg／kg于40分钟内持续静脉泵入，每隔0.3小时，通过Swan-Ganz导管和动脉、混合静脉血气分析，监测动物的血液动力学和氧合功能的变化，观察模型的复制及其稳定情况。结果：静脉注入内毒素后，约0.3小时动脉血压下降，此后血压有所回升，0.6小时后动脉血压再次明显下降(P＜0.01)，至(1.5±0.3)小时12只犬中11只达到感染性休克诊断标准，在随后的1小时观察期内模型能保持稳定的低动力循环状态；模型的心输出量、每搏量和左心室作功、体血管阻力、氧输送和氧摄取较基础值明显下降(P＜0.01)。结论：全麻和肌松状态下，较大剂量快速静脉泵入内 而方6印土学碎寸另q究主毕公枪丈毒素能复制实用、可靠的低动力循环型感染性休克犬模型，模型的氧合功能明显下降。 实验二：液体复苏对感染性休克犬血液动力学和氧代谢的影响目的：观察液体复苏对感染性休克犬血液动力学和氧代谢的影响。方法：采用内毒素静脉注入诱导的11 只感染性休克犬模型，输注0．9％氯化钠复苏至不同的肺动脉嵌顿压（PAWP）水平，通过右颈内静脉放置的肺动脉导管测定基础、休克1小时和不同水平复苏后血液动力学，分析动脉和混合静脉血气，计算氧代谢。结果：＊）与基础值比较，感染性休克犬平均动脉血压（MAPX心输出量K X左心室作功（LVSW）及体血管阻力①VR）分别下降了35．7％、29．2％、65．2％禾14．0％什均＜0刀1），氧输送①0。）下降46．9％W 0刀1），氧摄取（VO。）下降54．4％（＜0＊1）；（）复苏至PAWP为（8．710．9）nunHg时，MAP、CO、LVSW分别较休克增加 18．4％、38．9％、107．l％什均＜0＊1），降低 的S＊R则不受影响卜0．05），＊0。增加42，8WP＜0＊1），VO。基本不变卜0刀5）；＊）继续复苏至PAWP为＊．ltl．4）mmHg时，＊＊P、＊O、LV SW进一步增加23．0％。5．9％、11．7％o均＜0刀5XS＊R仍不受影响什卜0＊5），D02增加9．9％（＜0＊5），＊0二仍无明显变化汐＞0刀5）；N感染性休克后动脉血乳酸明显增加（＜O．05＞液体复苏后分别下降21．8％和27．3％汐＜0．05卜结论：充分液体复苏能明显增加感染性休克动脉血压、，0输出量和氧输送，但不能逆转血管阻力和氧摄取的降低。 实验三：液体复苏对感染性休克大多内脏血流灌注 和氧合功能的影响目的：研究液体复苏不同水平对感染性休克犬多内脏血流灌注和氧合功能的影响。方法：8只感染性休克犬模型，生理盐水复苏至不同肺动脉嵌顿压（PAWP）水平。用电磁血流量仪测定基础、休克1小时、不同复苏水平后肝动脉、门静脉和肠系膜上动脉血流量，分析动脉、门静脉、肝静脉和肠系膜上静脉血气，计算肝脏和肠道氧合。 ．6 ＄t44／－q4t4k44＃feL结果：＊）犬感染性休克后肝脏血流量（HBF和肠系膜上动脉血流量（＊＊＊n肠道灌注）分别减少叮．9％、61．8％（尸＜0刀1X氧输送① 0刁少52．＊％、81．1WP＜0＊1），氧摄取（＊0。）减少80．1％、三3．3％（＜0＊1）；口复苏至PAWP为指．7士OWmmHg时，HBF、SMABF较休克 1小时分别 土 加68．3％、啊＊％（＜0＊1），＊0。增加12．1％和10．3％（＜0刀5），＊0。增加12．5％和10刀％（＜0＊5）；（3）进一步复苏至PAWP为＊l士1，4）mmHg时，HBF、SMABF分别较休克1小时增加98．9％、85刀％（＜O刀1），＊＊增加33．3％和20．5％（＜0刀1），＊02增加31．3％和50刀％o＜0刀1卜结论：感染性休克后内脏灌注和氧合减少是不均一的，液体复苏后的增加亦是不同步的。充分液体复苏基本恢复肝脏灌注，但不能完全恢复肠道灌注。 实验更多还原

【Abstract】 The typical human cardiovascular response to septic shock is characterized by hypotension, lower systemic vascular resistance, the early development of myocardial depression, decrease blood flow of multiple splanchnic organ and incriminated function. Despite the continuous advances in monitor technologic and synthetic treatment, the mortality from septic shock remains high. This suggests the presence of septic mediators during septic shock that may be not inhibited. NO is known to play a major role. Many studies on septic animals or human, inhibiton or blockade of NO was beneficial, since it improved shock hemodynamic status. However, other documents described that NO blockaded was hazardous, since it worsened oxygen availability and blood perfusion of the splanchnic organ. How to remain the benefit of blockade NO in hemodynamics without an impairment in oxygen availability to the tisues are the unresolved problems in clinical practice. NO induces dilation of vascular and hypotension by activing soluble guanylate cyclase (sGC). In recently crimental studies on septic shock, NO synthase and sGC activation in splanchnic vascular tone are different, these differences may be result in improvement of hemodynamics without side effections of splanchnic oxygenation, which can be increased by increasing perfusion pressure.MB is an inhibitor of sGC. To blockade the effect of NO by inhibiting sGC with MB may represent a safer option. Effections of MB on hemodynamics and oxygenation of multiple splanchnic organs were observed in our study at first. Hemodynamics, blood flow of splanchnic organs, oxygenation and organ functions were recorded at status. Aim of the study was to predict the benefits which should be obtained with MBtreatment in septic shock.Parti. Experimental model of septic shock in dogs induced by endotoxin: a review and an evaluationObjective: To establish septic shock dog model by injection higher dose of endotoxin intravenously, then make a review and an evaluation of the animal model. Methods: In twelve anaesthetized and muscle relaxed mongrel dogs, 250~500μg/kg endotoxin were infused intravenously within 20-40 minutes. In order to determine whether septic shock was obtained during 2.5 hour, the parameters of hemodynamics and oxygenation were observed every 0.3 hour by Swan-Ganz catheter and blood gas was analysed. Results: After (1.5±0.3)hours of endotoxin infusion, eleven dogs satisfied septic shock criteria. Mean arterial pressure decreased after 0.3 hour of endotoxin infusion, then increased at low-moderate level and decreased significantly after 0.6 hour of administration endotoxin(P<0.01). It reached constant after one and half hours of endotoxin infusion. Cardiac output, left ventricular stroke work, systemic vascular resistance, oxygen delivery and oxygen uptake decreased remarkably below baseline(P<0.01). Conclusion: It is a practical and ideal model of dogs with septic shock which is characterized by hypodynamic and by deteriorating oxygenation through infusing higher dose of endotoxin intravenously.Part2. Effects of liquid resusciation on hemodynamics and oxygen metabilish in dogs with septic shock.Objective: To study the effects of liquid resusciation on hemodynamics and oxygen metabilish in dogs with septic shock. Methods; A model of septic shock was established by infusion 250ug/kg Escherichia coli endotoxin during 20 min in eleven dogs, which received isotonic salinefor resusciation. Hemodynamics was measured at baseline, shocked for 1 h and the different levels of pulmonary artery wedge pressure (PAWP) by Swan-Ganz catheter. Blood gas was analysed, then oxygen metabilish was calculated. Results: (l)Mean arterial pressure (MAP), cardiac output(CO), left ventricular stroke work (LVSW) and systemic vascular resistance (SVR) decreased significantly below baseline (decreased by 35.7%, 29.2%, 65.2% and 14.0%, respectively, P<0.01), Oxygen delivery (DO2) decreased by 46.9% (P<0.01), Oxygen uptake (VO2) decreased by 54.4% (P<0.01). (2)MAP, CO and LVSW increased signi更多还原