急性等容血液稀释时体循环和肺循环变化的实验研究

目的 :研究急性等容血液稀释 (ANHD)对体循环及肺循环的影响 ,指导临床ANHD的应用。方法 :10只健康成年杂种犬 ,麻醉后气管插管 ,控制呼吸 ,正常体温下 ,每只犬行三个水平的ANHD ,即中度 (HD1Hct约为 19% )、深度 (HD2 Hct约为 15 % )、极深度 (HD3 Hct约为 9% ) ,然后回输自家血 ,在血液稀释前、稀释后 30min、回输血后 15min分别测血液流变学、体循环和肺循环各指标。结果 :HD时血粘度 η渐下降。HD1、HD2 时 ,心输出量 (CO)和心脏指数 (CI)分别升高 41%和 48% ;心率 (HR)无明显变化 ,总外周阻力 (SVR)渐下降 ,平均动脉压 (MAP)渐下降 ;肺小动脉阻力 (PVR)渐下降 ,而平均肺动脉压力 (MPA)、肺动脉楔入压 (PCWP)、中心静脉压 (CVP)无明显变化。HD3 时 ,CO(CI)不再升高反而降低 ,HR仍无明显变化 ,SVR和MAP继续下降 ;PVR继续下降 ,MPA无明显变化 ,PCWP、CVP有所升高 ,回输血后各指标均有所回升。整个稀释过程中 ,心搏血量SV和心搏指数SVI,左室每搏作功指数LVSWI、右室每搏作功指数RVSWI的变化与CO(CI)的变化相似。结论 :中度、深度ANHD时 ,机体代偿 ,CO(CI)及SV(SVI)升高 ,SVR、PVR降低 ,有利于循环 ;极深度ANHD时 ,CO(CI)及SV(SVI)不再升高反而降低 ,MAP下降明显 ,MPA无明显变化 ,对体循环影响大 ,对肺?

Effects of acute normovolemic hemodilution on systemic circulation and pulmonary circulation in anesthetized dogs

Objective We administrated different degrees of acute normovolemic hemodilution (ANHD) in anesthetized dogs,investigating the effects of ANHD on systemic hemodynamic.Methods 10 healthy hybrid dogs,weighing 11～18 kg,were anesthetized with 6% sodium pentobarbital, endotracheal intubation was facilitated with vecuronium and ventilationcontrolled.The different degrees of ANHD,namely moderate(HD 1),severe(HD 2) and exetreme(HD 3) HD,were accomplished step by step exchanging whole blood with 4% Gelofusine. Hemorheology and hemodynamic variables were measured prior to HD and 30 mins after every step of hemodilution as well as 15 mins after reinfusion.Results The desired levels of hemodilution were obtained. The Hct decreased from (43.77±2.76)% to (19.43±1.97)% (HD 1),(14.73±0.99)% (HD 2) and (9.50±0.88)% (HD 3) ( P <0.01).During the HD 1 and HD 2, cardiac output(CO)and cardiac index (CI)were increased by 41% and 48% respectively ( P <0.05);HR was not changed significantly, SVR and PVR were decreased.MAP was decreased, but MPA,PCWP and CVP were not changed significantly;During the HD 3 CO(CI) did not increase but decreased,SVR,PVR and MAP continued to decrease,MPA were not changed significantly.Conclusions In moderate HD and severe HD CO(CI) were increased,but SVR and PVR were decreased.That is good for circulation;In exetreme HD CO(CI) were not increased but decreased,MAP continued to decrease,MPA were not changed significantly. It produced effect on systemic circulation significantly but not significantly on pulmonary circulation.