羟乙基淀粉对血液流变学影响的临床观察

羟乙基淀粉是胶体血浆代用品，常用于低血容量及休克的防治，主要作用机理是提高血浆胶体渗透压，维持和扩充有效血容量。此外，羟乙基淀粉还具有改善血液流变学的作用。本文观察手术病人术前输注羟乙基淀粉溶液后的血液流变学变化。     

中分子羟乙基淀粉扩容效果的实验研究

目的探讨6%羟乙基淀粉(6%HES200/0.5)的扩容效果。方法10只健康成年新西兰兔,125I-IgG标准计数后,自家兔耳缘静脉注射3min充分混匀,取血少许称重测量放射量计数,约2ml测量血红蛋白(Hb),并在20min内近心端静脉匀速输注6%HES200/0.510ml/kg;输入后取约2ml血再次测量Hb。计算中分子羟乙基淀粉输注后新西兰兔血容量和扩容系数。结果兔血容量Vi125(V1)为(232.5±38.9)ml;V2为(280.4±44.6)ml,6%HES200/0.5扩容量ΔV为(48.9±0.4)ml。结论中分子羟乙基淀粉在输注20min后显示明显扩容效果。     

血容量测定进展

动脉压、心率、中心静脉压和尿量等指标不能对实际的血容量变化进行定量分析，而血红蛋白、血球压积的变化了不能可靠地反映急性出血量。近年人们对传统的血容量测定法进行了改进和发展，本文介绍了以一氧化碳或浓缩的稳定同位素作为红细胞标记物以及用羟乙基淀粉作为血浆稀释剂行血容量测定。     

白蛋白葡聚糖和羟乙基淀粉治疗作用的比较

输入胶体是补液的重要组成部分。胶体主要有白蛋白、葡聚糖及羟乙基淀粉。扩容作用以葡聚糖最明显，羟乙基淀粉次之，白蛋白较差；三者都会发生过敏反应，葡聚糖发生率最高，危险性最大，白蛋白次之，羟乙基淀粉发生率最低；对肺肾功能的影响以白蛋白最明显，葡聚糖次之。     

血容量测定进展

动脉压、心率、中心静脉压和尿量等指标不能对实际的血容量变化进行定量分析,而血红蛋白、血球压积的变化也不能可靠地反映急性出血量。近年人们对传统的血容量测定法进行了改进和发展,本文介绍了以一氧化碳或浓缩的稳定同位素作为红细胞标记物以及用羟乙基淀粉作为血浆稀释剂行血容量测定。     

两种胶体预充液用于心肺转流的临床研究

目的研究羟乙基淀粉和琥珀酰明胶用于心肺转流(CPB)预充时对患者凝血功能及胶体渗透压的影响。方法 60例先天性非紫绀心脏病患者,随机均分为两组:羟乙基淀粉组以6%羟乙基淀粉130/0.4预充,琥珀酰明胶组以4%琥珀酰明胶预充。手术室及ICU根据分组情况亦分别输注羟乙基淀粉和琥珀酰明胶。于CPB前、给鱼精蛋白后、ICU6h测定激活凝血时间(ACT)、凝血速率(CR)及血小板功能(PF);于CPB前、CPB中、CPB后、ICU2h和6h测定胶体渗透压。结果给鱼精蛋白后和ICU6h,羟乙基淀粉组PF明显高于琥珀酰明胶组(P<0.05),其余指标差异无统计学意义。结论 6%羟乙基淀粉130/0.4与4%琥珀酰明胶作为胶体预充液在心肺转流中使用安全性相似。     

6％羟乙基淀粉130/0.4容量治疗对低血容量兔肠系膜微循环的影响

目的 评价6％羟乙基淀粉130/0.4容量治疗对低血容量兔肠系膜微循环的影响.方法 雄性成年家兔64只,体重2.0～ 2.3 kg,采用随机数字表法,将其随机分为4组(n＝16):对照组(C组)、低血容量组(HM组)、乳酸钠林格氏液组(RS组)和6％羟乙基淀粉130/0.4组(HES组).家兔麻醉后行右颈内静脉、股动脉和股静脉穿刺置管.C组不放血;M组经30 min股静脉放出30％血容量的血;S组和H组放血结束即刻经30 min右颈内静脉分别输注3倍放血量的乳酸钠林格氏液和等放血量的6％羟乙基淀粉130/0.4.于放血前(T0)、放血结束即刻(T1)、补液结束即刻(T2)和补液结束后30min(T3)时,记录MAP和HR,同时采集股动脉和股静脉血样,进行血气分析,计算氧供(DO2)、氧耗(VO2)和氧摄取率(ERO2);测定微动脉和微静脉的直径和血流速度.结果 与C组比较,HM组T1～3时HR加快,MAP降低,微血管直径缩小,血流速度减慢,T1时DO2升高(P＜0.05).与HM组比较,RS组T2时MAP升高,T2.3时HR减慢,T1～3时DO2和VO2升高,微动脉直径T2时增大,T3时缩小,T2.3时微静脉直径增大,微血管血流速度加快,HES组T2时MAP升高,T2.3时HR减慢,VO2和ERO2升高,微动脉和微静脉直径增大,血流速度加快(P＜0.05).与RS组比较,HES组T3时DO2、VO2和ERO2降低(P＜0.05).结论 6％羟乙基淀粉130/0.4容量治疗可改善低血容量兔肠系膜微循环,增加组织灌注,改善氧代谢.     

6％羟乙基淀粉130／0．4在小儿腹部手术中容量治疗的临床应用

目的 探讨6％羟乙基淀粉130／0．4在小儿腹部手术中容量治疗的应用效果。方法60例拟行腹部手术的患儿随机分为观察组和对照组,每组各30例。观察组术中容量治疗使用6％羟乙基淀粉130／0．4及晶体液;对照组未使用6％HES130／0．4,所使用的晶体液与观察组相同,可选用胶体液为浓缩红细胞。观察两组患儿手术前后心率、血压．总输液量及晶体液、胶体液、浓缩红细胞输入量等。记录观察组因输注6％羟乙基淀粉可能出现的不良反应,如：过敏（包括低血压、皮疹等）。结果两组输液总量无显著性差异。观察组与对照组相比：胶体液用量、晶体液用量、浓缩红细胞用量均有显著性差异,（P〈0．05）。观察组未发现因输注6％羟乙基淀粉130／0．4而出现的不良反应。结论6％羟乙基淀粉130／0．4可安全、有效的用于小儿腹部大手术中的容量治疗。     

体外循环心内直视术中6%羟乙基淀粉与明胶对渗透压和血液动力学的影响

羟乙基淀粉(Haes—sterils)是一种中分子量低取代级的淀粉类人工胶体,具有扩容作用良好、循环稳定效果佳、可改善氧供/氧耗、过敏性低等特点。本研究通过对6％羟乙基淀粉与明胶用于体外循环预充液及术中容量补充的比较,为人工胶体液临床应用提供客观依据。     

不同液体对健康成年志愿者扩容效果的比较

目的 比较6%羟乙基淀粉130/0.4、6%羟乙基淀粉200/0.5、琥珀酰明胶及乳酸钠林格氏液对健康成年志愿者的扩容效果.方法 健康成年男性志愿者24名,年龄21～40岁,体重56～78kg,随机分为4组(n=6),以125I法测定血浆容量并结合血细胞比容计算基础血容量;输液前于肘静脉抽血2 ml测定血红蛋白浓度,各组分别在45 min内静脉恒速输注6%羟乙基淀粉130/0.4(A组)、6%羟乙基淀粉200/0.5(B 组)、琥珀酰明胶(C组)和乳酸钠林格氏液(D组)750 ml.输液结束后每隔20分钟抽静脉血2 ml测定血红蛋白浓度,A组、B组和C组至输液后340 min、D组至输液后180 min,计算输液后血容量增加值(△BV)和液体潴留率(FR).结果 与输液前比较,A组和B组输液后80～340 min时血容量增加,C组输液后80～320 min时血容量增加,D组输液后80 min时血容量增加(P＜0.05);与A组比较,C组输液结束时、D组输液结束时至输液结束后180 min时△BV和FR降低(P＜0.05),且输液结束后180 min 时△BV和FR均为0;与B组比较,C组输液结束时、D组输液结束时至输液结束后180 min时△BV和FR降低(P＜0.05);与C组比较,D组输液结束时至输液结束后180 min时△BV和FR降低(P＜0.05);A组、B组和C组液体在血管内存留时间均＞340 min.结论 6%羟乙基淀粉130/0.4、6%羟乙基淀粉200/0.5和琥珀酰明胶较乳酸钠林格氏液的扩容效果好,维持时间长.     

Vasopressor hormone response following mesenteric traction during major abdominal surgery

Background : We investigated the vasopressor hormone response following mesenteric traction (MT) with hypotension due to prostacyclin (PGI₂) release in patients undergoing abdominal surgery with a combined general and epidural anesthesia. Methods : In a prospective, randomized, placebo-controlled study we administered 400 mg ibuprofen (i.v.) in 42 patients scheduled for abdominal surgery. General anesthesia was combined with epidural anesthesia (T4-L1). Before as well as 5, 15, 30, 45, and 90 min after MT we recorded plasma osmolality, hemodynamics and measured 6-keto-PGFlα (stabile metabolite of PGI₂), TXB₂ (stabile metabolite of thromboxane A₂) active renin, and arginine vasopressin (AVP) plasma concentrations by radioimmunoassay. Catecholamine levels were assessed by high-pressure liquid chromatography (HPLC) with electrochemical detection. Results : Following MT, arterial hypotension occurred along with a substantial PGI₂ release. This was completely abolished by ibuprofen administration. Although plasma levels of 6-keto-PGF_1α (1133 (708) vs. 60 (3) ng/L, median (median absolute deviation), P=0.0001, placebo vs. ibuprofen) remained significantly elevated, blood pressure was restored within 30 min after MT in the placebo group. At the same point in time plasma concentrations of TXB² (164 (87) vs. 58 (1) ng/L, P=0.0001), epinephrine (46 (33) vs. 14 (6) ng/L, P=0.001), AVP (41 ± (18) vs. 12 (7) ng/L, P=0.0004), and active renin (27 (12) vs. 12 (4) ng/L, P = 0.001) were significantly higher in placebo-treated patients. Conclusion : Under combined general and epidural anesthesia arterial hypotension following MT due to endogenous PGI₂ release is associated with enhanced release of AVP, active renin, epinephrine and thromboxane A₂, presumably contributing to hemodynamic stability within 30 min after MT.     

A Teaspoon Pump for Pumping Blood with High Hydraulic Efficiency and Low Hemolysis Potential

Abstract: Virtually all blood pumps contain some kind of rubbing, sliding, closely moving machinery surfaces that are exposed to the blood being pumped. These valves, internal bearings, magnetic bearing position sensors, and shaft seals cause most of the problems with blood pumps. The original teaspoon pump design prevented the rubbing, sliding machinery surfaces from contacting the blood. However, the hydraulic efficiency was low because the blood was able to "slip around" the rotating impeller so that the blood itself never rotated fast enough to develop adequate pressure. An improved teaspoon blood pump has been designed and tested and has shown acceptable hydraulic performance and low hemolysis potential. The new pump uses a nonrotating "swinging" hose as the pump impeller. The fluid enters the pump through the center of the swinging hose; therefore, there can be no fluid slip between the revolving blood and the revolving impeller. The new pump uses an impeller that is comparable to a flexible garden hose. If the free end of the hose were swung around in a circle like half of a jump rope, the fluid inside the hose would rotate and develop pressure even though the hose impeller itself did not "rotate"; therefore, no rotating shaft seal or internal bearings are required.     

Microspheres Based Detoxification System: A New Method in Convective Blood Purification

Abstract: A variety of protein-bound or hydrophobic substances, accumulating as a result of pathologic conditions such as exogenous or endogenous intoxications, are removed poorly by conventional detoxification methods because of low accessibility (hemodialysis), insufficient adsorption capabilities (hemosorption), low efficiency (peritoneal dialysis), or economic limitations (high-volume plasmapheresis). Combining advantages of existing methods with microspheric technology, a module-based system was designed. Major operating parameters of the latter can be modified to allow for adjustment to individual clinical situations. An extracorporeal blood circuit including a plasmafilter is combined with a secondary high-velocity plasma circuit driven by a centrifugal pump. Different microspheric adsorbers can be combined in one circuit or applied in sequence. Thus, a prolonged treatment can be tailored using specially designed selective adsorber materials. Comparing this system with existing methods (high-flux hemodialysis, molecular adsorbent recycling system), results from our in vitro studies and animal experiments demonstrate the superior efficiency of substance removal.     

Tissue perfusion in relation to cardiac output during continuous positive-pressure ventilation and administration of propranolol or verapamil

Background : Our objective was to determine whether administration of propranolol or verapamil modifies the hemodynamic adaptation to continuous positive-pressure ventilation (CPPV), in particular the regional distribution of cardiac output (CO).
Methods : General hemodynamics and regional blood flows assessed by microsphere technique (15 (μm) were recorded in 16 anesthetized pigs during spontaneous breathing (SB) and CPPV with 8 cm H₂O end-expiratory pressure (CPPV8) before and after intravenous administration of propranolol (0.3 mg · kg⁻¹ followed by 0.15 mg · kg⁻¹ · h⁻¹, n=8) or verapamil (0.1 mg · kg⁻¹ followed by 0.3 mg · kg⁻¹ · h⁻¹, n=8).
Results : CPPV8 depressed CO by 25% without shifts in its relative distribution with the exception of a noteworthy increase in adrenal perfusion. Propranolol increased arterial blood pressure, and due to a fall in heart rate, CO dropped by 25%. The kidneys and, to a lesser extent, the splanchic region and central nervous system received increased fractions of the remaining CO at the expense of skeletal muscle flow. Similar patterns were seen during SB and CPPV8 such that the combination of propranolol and CPPV8 depressed CO by 50%. The circulatory effects of verapamil were less evident but myocardial perfusion tended to increase.
Conclusions : The combination of propranolol or verapamil with CPPV does not result in any specific hemodynamic interaction in anesthetized pigs, except that the combined effect of propranolol and CPPV may severely reduce CO.     

Bariatric Surgery in Some "Central and East-European (former Eastern bloc)"Countries - Current Status and Prediction for the Next Millennium

Background: Obesity is increasing globallly, including in the formerly "Eastern Bloc" countries. Methods: A survey was made of obesity and bariatric surgery. Results: In the 8 East and Central European countries studied, with total population 300 million, roughly 43% of the population was overweight (BMI 25-30), 23% obese (BMI > 30), with about 15 million people morbidly obese (BMI > 40). From 0-10 morbidly obese individuals/100,000/year undergo bariatric surgery. Conclusion: Most countries were found to provide inadequate treatment for obesity.The majority of the morbidly obese are not treated effectively. However, health-care awareness of obesity and bariatric surgeons are slowly increasing.     

Volatile anaesthetics reduce adhesion of blood platelets under low-flow conditions in the coronary system of isolated guinea pig hearts

Background : Inhibitory effects of volatile anaesthetics on platelet aggregation have been demonstrated in several studies. However, the influence of volatile anaesthetics on intracoronary platelet adhesion has not been elucidated so far.
Methods : Isolated hearts of guinea pigs were perfused with buffer in the absence or presence of volatile anaesthetics (0.5 and 1 MAC) at constant coronary flow rates of 5 ml/min for 25 min, then 1 ml/min for 30 min and again 5 ml/min for 10 min. Before, during and after low-flow perfusion, a bolus of human platelets was applied into the coronary system. To simulate thrombogenic conditions, 0.3 U/ml human thrombin was infused during low-flow perfusion and reperfusion. The number of platelets sequestered to the endothelium was calculated from the difference between coronary in- and output of platelets. The myocardial production of lactate and consumption of pyruvate and coronary perfusion pressure were also determined.
Results : At a flow rate of 5 ml/min only about 3% of the applied platelets did not emerge from the coronary system, in any group. In contrast, 13.1±1.2% (mean±SEM) of infused platelets became adherent in low-flow perfusion in the control group without anaesthetic. The adherence was reduced with each 1 MAC isoflurane (to 6.2±1.2%), sevoflurane (to 4.4±0.9%) or halothane (to 3.2±1.5%) (each P <0.05 vs. control). Volatile anaesthetic, 0.5 MAC, did not inhibit platelet adhesion to a statistically significant extent in any case. Perfusion pressure and metabolic parameters were not statistically different between the control and the hearts exposed to anaesthetics.
Conclusion : Volatile anaesthetics in a concentration of 1 MAC can reduce the adhesion of platelets in the coronary system under reduced flow conditions. This action does not arise from vasodilation or inhibition of ischaemic stress.     

Synergistic interaction between the effects of propofol and midazolam with fentanyl on phrenic nerve activity in rabbits

Background: It has been shown that the depressive effects of both propofol and midazolam on consciousness are synergistic with opioids, but the nature of their interactions on other physiological systems, e. g. respiration, has not been fully investigated. The present study examined the effect of propofol and midazolam alone and in combination with fentanyl on phrenic nerve activity (PNA) and whether such interactions are additive or synergistic. Methods: PNA was recorded in 27 anaesthetised and artificially ventilated rabbits. In three groups, propofol, fentanyl and midazolam were administered intravenously in incremental doses to construct dose-response curves for the depressant effects of each one on PNA. In another two groups, the effect of pretreatment with either fentanyl 1 μg · kg^?1 i. v. or midazolam 0.05 mg · kg^?1 i. v. on the effects of propofol and fentanyl respectively on PNA were studied. Results: Propofol and fentanyl caused a dose-dependent depression of PNA with complete abolition at the highest total doses of 16 mg · kg^?1 i. v. and 32 μg · kg^?1 i. v., respectively. In contrast, midazolam in incremental doses to a total of 0.8 mg · kg^?1 reduced mean PNA by 63%, but approximately 12% of PNA remained at a total dose as high as 6.4 mg · kg^?1. The mean ED₅₀s, calculated from dose-response curves, were 5.4 mg · kg^?1, 3.9 μg · kg^?1 and 0.4 mg · kg^?1 for propofol, fentanyl and midazolam, respectively. Initial doses of either fentanyl 1 μg · kg^?1 i. v. or midazolam 0.05 mg · kg^?1 i. v. acted synergistically with subsequent doses of either propofol or fentanyl to abolish PNA at total doses of 8 mg · kg^?1 and 8 μg · kg^?1, respectively. Conclusion: Fentanyl has a synergistic interaction with both propofol and midazolam on PNA and hence potentially on respiration.     

Influence of dopexamine hydrochloride on haemodynamics and regulators of circulation in patients undergoing major abdominal surgery

Background: Catecholaminergic support is often used to improve haemodynamics in patients undergoing major abdominal surgery. Dopexamine is a synthetic vasoactive catecholamine with beneficial microcirculatory properties. Methods: The influence of perioperative administration of dopexamine on cardiorespiratory data and important regulators of macro- and microcirculation were studied in 30 patients undergoing Whipple pancreaticduodenectomy. The patients received randomized and blinded either 2 μg · kg^?1 · min^?1 of dopexamine (n=15) or placebo (n=15, control group). The infusion was started after induction of anaesthesia and continued until the morning of the first postoperative day. Endothelin-1 (ET-1), vasopressin, atrial natriuretic peptide (ANP), and catecholamine plasma levels were measured from arterial blood samples. Measurements were carried out after induction of anaesthesia, 2 h after onset of surgery, at the end of surgery, 2 h after surgery, and on the morning of the first postoperative day. Results: Cardiac index (CI) increased significantly in the dopexamine group (from 2.61±0.41 to 4.57±0.78 1 · min^?1 · m^?2) and remained elevated until the morning of the first postoperative day. Oxygen delivery index (DO₂I) and oxygen consumption index (VO₂I) were also significantly increased in the dopexamine group (DO₂I: from 416±91 to 717±110 ml/m² · m²; VO₂I: from 98±25 to 157±22 ml/m² · m²), being significantly higher than in the control group. pHi remained stable only in the dopexamine patients, indicating adequate splanchnic perfusion. Vasopressive regulators of circulation increased significantly only in the untreated control patients (vasopressin: from 4.37±1.1 to 35.9±12.1 pg/ml; ET-1: from 2.88±0.91 to 6.91±1.20 pg/ml). Conclusion: Patients undergoing major abdominal surgery may profit from prophylactic perioperative administration of dopexamine hydrochloride in the form of improved haemodynamics and oxygenation as well as beneficial influence on important regulators of organ blood flow.     

Systemic analgesia adapted to the children's condition

A concept of balanced analgesia using nonsteroidal anti-inflammatory drugs (NSAIDs), paracetamol (acetaminophen), opioids, and corticosteroids can also be used in patients with pre-existing illnesses. NSAIDs are the most effective treatment for acute pain of moderate intensity in children; however, these drugs should be avoided in patients at increased risk for serious side effects, e.g. patients with renal impairment, bleeding tendency, or extreme prematurity. NSAIDs can be given with minimal risks to the younger child with mild to moderate asthma, and, in these patients, the use of steroids can be encouraged; in addition to their antiemetic and analgesic action, a beneficial effect on asthma symptoms can be expected. In the non-intubated child with cerebral trauma, exaggerated sedation caused by opioids and increased bleeding tendency caused by NSAIDs must be avoided. In neonates and small infants, the oral administration of sucrose or glucose is helpful to minimize pain reaction during short uncomfortable interventions.     

A comparison of the inhibitory effects of four volatile anaesthetics on the metabolism of chlorzoxazone, a substrate for CYP2E1, in rabbits

Background: Halothane inhibits in vitro and in vivo activity of cytochrome P-450 (CYP) 2E1. There are several fluorinated volatile anaesthetics besides halothane, and most of them are defluorinated by CYP2E1. It is unclear whether other fluorinated anaesthetics inhibit the in vivo activity of CYP2E1.
Methods: We compared the inhibitory effects of therapeutic concentrations of four inhalational anaesthetics, halothane, enflurane, isoflurane, and sevoflurane, on chlorzoxazone metabolism in rabbits receiving artificial ventilation.
Results: All four inhalational anaesthetics decreased arterial blood pressure and increased plasma chlorzoxazone concentration. However, no significant differences in the plasma chlorzoxazone concentration were found between the four anaesthetics. The estimated chlorzoxazone clearance increased after beginning inhalation with all four agents, but no significant difference in clearance was noted between agents.
Conclusions: At therapeutic concentrations, the in vivo inhibitory effect on chlorzoxazone metabolism was similar for all four inhalational anaesthetics examined, even though their chemical characteristics and extent of hepatic metabolism differ considerably.