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?     

支气管镜检查在气管和支气管结核诊断中的作用

目的探讨气管、支气管结核的临床特征及支气管镜检查在气管、支气管结核诊断中的作用。方法回顾性分析经Olympus电子或纤维支气管镜检查,后经病理学或抗酸染色证实为气管、支气管结核216例患者的临床资料及支气管镜检查资料。结果临床主要症状为刺激性干咳(72．7％)和间断性咯血(34．7％),缺乏典型的结核中毒表现。胸部影像学检查以肺内片状阴影(31．0％)和肺不张(24．1％)多见,影像学无明显异常者占16．7％。气管镜下表现为肉芽增殖型 (36．1％)、炎症浸润型(31．0％)、溃疡坏死型(24．1％)、瘢痕狭窄型(8．8％)。病变部位左肺 (56．2％)多于右肺(37．6％),左主支气管受累比例最大(26．9％),病变遍及所有叶、段支气管。 216例中经病理学诊断178例(82．4％),毛刷涂片抗酸染色细菌学诊断68例(31．5％)。结论气管、支气管结核缺乏特异性临床表现,误诊率较高,不重视支气管镜检查是误诊主要原因。支气管镜检查是气管、支气管结核最可靠和最准确的诊断方法。     

血液稀释疗法对严重烧伤患者血液流变学特性的影响

目的 通过在严重烧伤早期应用血液稀释疗法，研究机体血液流变学特性的改变。方法 选择伤后6h内住院的成年男性严重烧伤患者30例，随机分为对照组与观察组。对照组患者常规进行体液复苏治疗，观察组患者体液复苏治疗同对照组。并于伤后24h内在血流动力学监测下进行血液稀释。二组患者分别于伤后8，16，24，48h测定全血粘度、血细胞比容、红细胞变形指数、红细胞聚集指数等血液流变学指标。结果 ①观察组患者进行血液稀释后，心输出量(CO)、中心静脉压(CVP)、平均动脉压(MAP)、肺动脉楔嵌压(PAWP)等反映血流动力学的指标有所改善。②对照组患者全血粘度、血细胞比容、红细胞聚集指数等血液流变学指标伤后显著增加，红细胞变形指数显著下降。虽经补液治疗，上述指标仍于伤后24h达峰值，伤后48h才接近正常范围；而观察组患者进行血液稀释后上述指标明显改善，伤后24h基本达正常水平。结论 严重烧伤早期应用血液稀释疗法是安全的，能有效地改善血液流变学指标。从而大大提高体液复苏的效果，尽快恢复循环血容量，有效防治休克。     

The effects of normovolemic hemodilution with dextran-40 on acute myocardial ischemia/ reperfusion injury in rabbits

Summary The effects of decreasing blood viscosity by normovolemic hemodilution with dextran-40 or normal saline (NS) on myocardial lipid peroxides, Superoxide dismutase, infarct size and left ventricular function during acute myocardial ischemia/reperfusion were studied in rabbit’s. It was found that normovolemic hemodilution with dextran-40 could decrease the content of ischemic myocardial malondialdehyde and preserve ischemic myocardial superoxide dismutase activity after 1 h of coronary occlusion followed by 1 h of reperfusion. However, after administration of NS only a tendency in this aspect exhibited without statistical significance. Besides, hemodilution with dextran-40 reduced infarct size and improved left ventricular systolic function after 1 h of ischemia followed by 23 h of reperfusion. These results suggest that normovolemic hemodilution with dextran-40 may have anti-injury effect on acute myocardial ischemia/reperfusion to a certain degree.     

Effects of acute isovolemic hemodilution and anesthesia on regional function in left ventricular myocardium with compromised coronary blood flow

The effects of progressive, isovolemic hemodilution using Dextran 70 and the effect of halothane (0.7, 0.9, 1.1, and 1.3% end-tidal, administered randomly at each level of hemodilution) on global cardiovascular and regional LV contractile functions were investigated in 24 dogs with induced critical constriction of the left anterior descending coronary artery (LAD). Two additional groups of six dogs each (with and without LAD stenosis) not undergoing hemodilution served as time controls. Regional LV contractile function was assessed by sonomicrometry in the flow-compromised apical LAD territory, as well as in three non-compromised LV areas supplied by the left circumflex coronary artery. Regional myocardial function was found to be stable throughout the study period of 4-5 h in both time control groups. Mean arterial and coronary perfusion pressures as well as LV dP/dtmin decreased (P < 0.01) during hemodilution. LV dP/dtmax remained unchanged, and heart rate and LVEDP increased slightly (P < 0.05). Systolic shortening (SS) in the LAD territory was unchanged at a hematocrit (HCT) of 33.5 +/- 0.3% (mean +/- s.e. mean), and decreased marginally at an HCT of 24.2 +/- 0.1% (SS of 17.4 +/- 1.0% as compared to 20.2 +/- 1.6% at critical constriction (CC), P < 0.05). No increase in post-systolic shortening (PSS) occurred in the compromised area. Severe LAD dysfunction was observed in the LAD territory at an HCT of 14.9 +/- 0.1%, as systolic shortening decreased (11.8 +/- 1.1%, P < 0.01 vs CC) and PSS increased (31.2 +/- 3.4%, P < 0.01 vs CC). The effects of hemodilution on global cardiovascular and regional myocardial functions were unaffected by halothane.(ABSTRACT TRUNCATED AT 250 WORDS)     

Hemodilution - possibilities and safety aspects

Normovolemic hemodilution is an essential part of the overall strategy to avoid exposure of patients to the hazards of homologous blood transfusions. It includes beneficial effects on the flow properties and flow conditions of blood. A hematocrit of 30% can be regarded as an optimal compromise between the fluidity and the oxygen content of the blood. Compensatory responses such as increased cardiac output and stroke volume occur following hemodilution. In patients with compromised coronary reserve the degree of hemodilution that is tolerated has to be carefully considered. Therefore specific selection criteria for patients to be preoperatively hemodiluted are needed. For reasons of safety, efficiency and practicability colloid solutions rather than crystalloid solutions should be used for intentional hemodilution.     

羟乙基淀粉130/0.4急性高容量血液稀释对血液流变学和凝血的影响

目的：应用羟乙基淀粉130／0．4（商品名称万汶）溶液对实验犬行急性高容量血液稀释（AHHD）后观察血液流变特性和凝血指标的变化，为围术期AHHD方案的制定提供实验依据。方法：实验犬随机分为万汶组（A组）和林格氏液组（B组），各10只。麻醉后以60ml／kg，15ml／min分别输注，达到高容量血液稀释状态，并维持血循环指标在正常范围。检测稀释前（T1）、稀释后30min（T2）及稀释后60min（T3）血液流变学指标和凝血指标等。结果：①AHHD后两组全血黏度、Het均降低，A组的全血黏度明显低于B组（P〈0．05），A组的红细胞变形指数升高，红细胞聚集指数降低，而B组的红细胞聚集指数增高，且两组之间差异显著（P〈0．05）；②A组在AHHD后PT、APTT与T1相比有延长，但无显著性差异（P〉0.05），纤维蛋白原定量降低显著，并与B组差异明显（P〈0．05）。结论：使用万汶行一定程度AHHD对实验犬可以保持血液循环功能稳定，优化血液流变学状态，有利于微循环灌注，对凝血功能影响小。     

低分子右旋糖酐等容血液稀释对家兔急性心肌缺血/再灌注损伤的影响

本实验观察了低分子右旋糖酐或生理盐水等容血液稀释对家兔急性心肌缺血/再灌注损伤的影响。结果表明:两种溶液稀释血液均可降低缺血心肌再灌时全血粘度,但右旋糖酐等容血液稀释对降低缺血心肌再灌后心肌组织脂质过氧化物及保护心肌超氧化物歧化酶活性的效应明显高于生理盐水等容稀释。此外右旋糖酐等容血液稀释尚可改善缺血心肌再灌后心功能及控制梗塞灶的扩大。结果提示:低分子右旋糖酐等容血液稀释具有一定程度的抗再灌损伤效应,其机理似与降低血液粘滞性改善微循环及抗氧自由基的作用有关。