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1、Influence of Hypothermia on the Property ofHemorheologyof RabbitsAbstract: Objective: To study the influence of hypothermia onthehemorheology of rabbits and the effects of Shenfu Injectionto the hyperviscosityin the modelofhypothermia rabbits.Methods: 40 rabbits were divided randomly into 4 groupsco
2、ntrolgroup , hypothermia ( body temperature, Tb = 251)groupandtwo Shenfu groups. The 3% pentobarbital-anesthetized rabbitswereventilated after intubation. Then ShenFuInjection and 0.9%normal saline were injected into treated animals and controlrespectively. All rabbits were injected fentanyl and ard
3、uan beforehypothermia .Except for control group, all rabbits Tb werelowered from 37 to 251and maintained3hours by surfacecooling. Their mean arterial pressure（MAP） and Tbhadbeenmonitored during the all experiment. Blood samples (2.5ml) weretaken immediately before hypothermia, Tb lowering at 25 ,sta
4、rting warming and warming end . All rheological assays werecarried out immediately atroomtemperature (22 1).Results:we have developed an animal model in which stable hypothermia couldbe established withoutthe cardiac bypass （CPB）.This model thusoffers the investigation of variousrheologicalassaysdur
5、ingprolongedhypothermia . The MAP of all rabbits decreasedsignificantly after anesthesia. The MAP of the control rabbits3treated with saline intravenously increased gradually with timewhile that of the hypothermia and the rabbits treated with Shenfudecreased continuously in the process ofhypothermia
6、. The MAPofthe last group animal increased gradually after warming. TheMAP of the hypothermiarabbitsishigherthanthat of thetreated with Shenfu rabbitswhen Tb had reached 25C, startingwarming and warming end (P 0.05). The MAP change between twogroups of rabbits treated with ShenFu did not make any si
7、gnificantdifference. The hemorheology parameters with great change hadntbeen observed in the control group. Inthe hypothermiagroup, theviscosity of blood increased progressively to 150% of that at 36 when body temperature was lowered to 25 . But that ofShenFu-treated rabbits was lowered attheir Tb h
8、ad reached 25(P 0.05). Conclusions: A rabbit model had been developedinwhichstable deep hypothermia could be established. The MAP ofhypothermiarabbitsdecreased,bloodviscosityincreased,hematocrit(HCT) and plasma viscosity did not make any significantdifference . The blood viscosity of hypothermia rab
9、bits may bedecreased by Shenfu Injection .4Key words: Clampedhypothermia/property ofhemorheology/ ShenfuInjectoin /rabbits model5前言控制性低温（以下简称低温）即应用药物、物理等方法将机体的温度降至预定温度范围内，以有效地降低机体的代谢，达到保护心、脑等重要脏器的目的，是体外循环（cardiac bypass CPB）心内直视手术中重要的辅助措施。但是，随着机体温度的降低，相应的并发症也逐渐增多。Tze-FL1碍和感染等，这些并发症的发生常伴有血液流变性的改变；反之，
10、血液流变性的改变又可以加剧这些并发症。血液流变学是一门旨在研究血液及其组成成分的流动和变形特性，以及这种特性对循环功能乃至全身功能和代谢影响的科学，现已逐渐发展为一门独立的学科,而血液流变性(property of emorheology )，即血液及其有形成分的流变学特性，包括血液的粘弹性、触变性、红细胞的变形性和聚集性以及血小板的粘附和聚集性等等，对于循环功能，尤其是微循环有着十分重要的意义。事实上，即使在心脏、血管和血液容量都正常的情况下，仅仅由于较严重的血液流变性改变，就能引起机体循环功能的障碍，并且进一步导致其它一系列的功能和代谢的变化。在血液流变性的改变中，尤以全血粘度的增高（高粘
11、滞血症）和红细胞脆性的改变对机体生理功能的影响最大，前者可进一步加剧微循环障碍，后者可增加体外转流中红细胞的破坏。目前，对低温引起的血液流变学改变及其机制还不十分清楚，预防低温时高粘滞血症的主要措施液是血液稀释2，温度越低，对血3液灌注随着稀释度重新分配，在过度稀释的情况下，由于可能造成肝、肾功能的损害特别是对未成熟儿的影响最大4，5。另外，在临床上有一些合并心肺疾病的病人需要较高的血红蛋白水平维持氧的传输，因此除了血液稀释之外，可否采用药物减轻低温引起的高粘滞血症是临床尚需解决的问6等研究发现 ，低温的并发症主要有呼吸抑制、心功能抑制、凝血功能障液的稀释度要求越高 。然而，近年也有研究表明，
12、机体各组织器官的血题。目前，临床上在许多手术中使用参附改善心功能及血液粘滞度6，7，但在低温条件下对血液流变性是否具有改善作用及作用机制尚待进一步探讨。本研究采用家兔建立低温动物模型，利用 FASCO-全自动连续切变血液粘度快测仪能够灵敏调控温度的特点，探讨低温实施过程中血液流变性的改变，并观察参附注射液的作用，为临床采用低温时克服其对血液流变性的不利影响探索新的途径。7材料与方法1实验材料1.1实验动物：本实验选用日龄和体重相近的健康成年日本大耳白兔 40只(普通动物级，雌雄不拘，由泸州医学院动物科提供)，日龄 120-125 天，体重 2.40.27 kg；单笼喂养，专人负责打扫卫生，每天喂食 3 次，采用其已习惯的合理食谱喂养 1-2 周。1.21.3动物手术器材：动物手术操作台、常规动物手术
