全髋关节置换术髋臼假体周围骨折的临床特征及其影响因素分析

目的观察全髋关节置换术髋臼假体周围骨折的临床特征,分析初次全髋关节置换术髋臼假体周围骨折的影响因素。方法回顾性分析自2013-01—2018-06完成的584例初次或翻修全髋关节置换术,17例出现髋臼假体周围骨折,初次手术13例,翻修手术4例。比较初次全髋关节置换术假体周围骨折组与未骨折组在性别、年龄、体重指数、手术侧别、疾病类型、手术入路、骨质疏松状态、假体类型、假体覆盖比例及主刀医师手术量方面的差异。结果全髋关节翻修手术中髋臼假体周围骨折发生率高于初次全髋关节置换术,差异有统计学意义(P<0.05)。多因素Logistic回归分析结果显示疾病类型(髋关节发育不良、类风湿性关节炎)、合并骨质疏松、生物型假体、假体覆盖比例>80%、主刀医师手术量≤80台/年是初次全髋关节置换术髋臼假体周围骨折的危险因素。结论全髋关节翻修手术中髋臼假体周围骨折发生率高于初次手术。对于髋关节发育不良、类风湿性关节炎、合并骨质疏松患者,以及选用生物型假体、假体覆盖比例>80%、主刀医师经验不足时,初次全髋关节置换术中需要警惕髋臼假体周围骨折发生。     

髋关节置换术中股骨假体周围骨折危险因素的分析

目的分析髋关节置换术中股骨假体周围骨折的发生情况和危险因素。方法选择本组自2002年1月至2008年12月所有行初次和翻修髋关节置换术患者共3021髋(初次置换术2718髋,翻修术294髋),分析术中股骨假体周围骨折的发生情况,并用Logistic回归分析骨折发生的相关因素,包括性别、年龄、术前诊断、假体类型、固定方式。用2检验进行初次置换和翻修术中发生骨折的差异性检验。结果总的术中股骨假体周围骨折发生率为5.7%(173/3021),其中初次置换发生率为4.0%(110/2718),翻修术发生率为21.4%(63/294)。初次置换应用骨水泥股骨假体术中骨折发生率为1.9%(8/429),非骨水泥股骨假体术中骨折发生率为4.5%(102/2289),初次置换术中骨折82.7%(91/110)发生于干骺端;翻修术应用骨水泥股骨假体术中骨折发生率为18.8%(21/112),非骨水泥股骨假体术中骨折发生率为23.1%(42/182),翻修术术中骨折62%(39/63)发生于骨干部。Logistic回归分析显示:初次髋关节置换术中骨折的危险因素包括性别、术前诊断、固定方式、假体类型;翻修术性别、年龄、假体固定方式不是引起术中骨折的危险因素。应用2检验,翻修术中股骨假体骨折的风险与初次置换相比差异有统计学意义(P0.000),OR值为6.5,95%CI(4.6,9.1)。结论初次髋关节置换术中股骨假体周围骨折的发生率为4.0%,主要发生于干骺端(83.6%),女性、髋关节发育不良、髋部骨折、高位脱位、非骨水泥固定是术中骨折的危险因素;髋关节翻修术中股骨假体周围骨折的发生率(21.4%),远高于初次髋关节置换术,主要发生于骨干部(61.9%),骨折的发生与否可能主要取决于翻修时的骨质情况,性别、年龄、假体固定方式并不是主要的影响因素。     

髋关节置换术治疗老年股骨颈骨折的Meta分析

目的对国外有关人工髋关节置换术治疗老年股骨颈骨折的研究文献进行分析,评价老年股骨颈骨折的治疗效能。方法计算机检索PubMED和Ovid等数据库,检索时间从1991～2007年,有关人工关节置换治疗老年股骨颈骨折的文献资料。比较人工关节置换手术的死亡率、脱位、关节翻修率、关节功能。对数据进行异质性检验,用Meta分析方法对数据进行处理,估计其综合OR值和95%CI。结果共纳入10篇相关的、以半髋和全髋关节置换术对照治疗老年股骨颈骨折的文献。研究结果提示两者的死亡率之间无明显差异;脱位率和翻修率之间Q值分别为4.03和2.78,P0.1,不存在异质性,总体效应的P0.01,全髋关节置换术的脱位率高,但是翻修率低于半髋关节置换术;关节功能Harris评分的Q=23.94,P0.1,存在异质性,总体效应的P0.01,RR=0.79,OR=0.35,95%CI(0.23,0.53),全髋关节置换术后髋关节功能明显优于半髋关节置换术后的患者。结论全髋关节置换术优于半髋关节置换术,在选择关节置换治疗老年股骨颈骨折的时候,尽量行全髋关节置换术。对于不能耐受全髋关节置换手术和预期寿命低于3年的患者,则采用半髋关节置换术。     

全髋关节置换术后假体周围感染的独立危险因素分析

目的探讨全髋关节置换术后假体周围感染的相关危险因素。方法回顾性分析自2014-01—2017-12完成的516例初次全髋关节置换术,观察术后1年内是否发生假体周围感染,然后分为感染组与未感染组。比较2组在性别、年龄、体重指数、术前血红蛋白、心脏病史、呼吸系统病史、糖尿病史、假体类型、手术时间、术中出血量、术中输血量、引流放置情况方面的差异。结果术后1年内有21例(4.07%)发生假体周围感染。单因素分析结果显示,感染组与未感染组在体重指数、心脏病史、糖尿病史、手术时间方面差异有统计学意义(P <0.05);感染组与未感染组在性别、年龄、术前血红蛋白、呼吸系统病史、假体类型、术中出血量、术中输血量、引流放置情况方面差异无统计学意义(P>0.05)。Logistic多元回归分析结果显示,肥胖[OR=0.216,95%CI(0.998,1.006),P=0.009]与手术时间[OR=1.035,95%CI(1.009,1.060),P=0.007]为全髋关节置换术后假体周围感染的独立危险因素。结论肥胖及手术时间延长是初次全髋关节置换术后假体周围感染的危险因素,而假体周围感染与是否合并基础疾病无关。根据患者的体重情况优化手术策略、缩短手术时间可能有利于降低全髋关节置换术后假体周围感染风险。     

髋关节翻修治疗骨缺损应用组配式假体与涂层长柄假体临床疗效的Meta分析

[目的]通过Meta分析评价两种非骨水泥假体:生物型组配式假体与涂层长柄假体,在髋关节翻修术治疗骨缺损时临床疗效的差异。[方法]文献检索PubMed、Ovid、CochraneLibrary、ScienceDirect、SpringerLink数据库,根据纳入和排除标准筛选文献,收集组配式假体与涂层长柄假体在髋关节翻修术中应用的高质量随机对照研究,提取相关数据,采用Review Manager 5.0软件进行Meta分析。[结果]共纳入8篇随机对照研究(Jadad评分3⁵分)。Meta分析结果显示,组配式假体与涂层长柄假体在髋关节翻修术后并发症的发生率无统计学差异RR=1.12,95%CI(0.96,1.32),P=0.15;组配式假体在髋关节翻修术后假体塌陷的发生率低于涂层长柄假体RR=0.28,95%CI(0.08,0.95),P=0.04;术后疼痛的发生率也低于涂层长柄假体RR=0.45,95%CI(0.22,0.94),P=0.03;两种假体在髋关节翻修术后假体无菌性松动的发生率无统计学差异RR=1.39,95%CI(0.21,9.39),P=0.74。[结论]髋关节翻修术应用组配式假体相对于涂层长柄假体可以减少术后疼痛和假体塌陷的发生率。     

膝关节假体周围感染危险因素的荟萃分析

[目的]运用荟萃分析评价影响膝关节假体周围感染(periprosthetic joint infection, PJI)的相关危险因素。[方法]利用中国知网(CNKI)、万方数据库、PubMed等数据库,检索2014年1月～2019年11月期间国内外公开发表的PJI文献。严格评价纳入研究的质量并提取数据,采用Revman5.3软件进行荟萃分析。[结果]共纳入9篇文献,累计总病例数7473例,其中发生术后假体周围感染283例。影响膝关节假体周围感染的危险因素有患者年龄[OR=2.80,95%CI (1.91,4.10),P0.05]、合并糖尿病[OR=5.14,95%CI (2.81,9.41),P0.05]、手术时间[OR=2.64,95%CI (1.25,5.58),P0.05]、吸烟[OR=2.60,95%CI (1.54,4.39),P0.05]、合并炎性疾病[OR=12.56,95%CI (5.08,31.01),P0.05]、激素使用[OR=6.06,95%CI (1.78,20.63),P0.05]、术后拔引流管时间[OR=4.58,95%CI (1.88,11.15),P0.05]、肥胖[OR=1.23,。95%CI (1.11,1.36),P0.05]。[结论]患者年龄大、合并糖尿病、手术时间长、吸烟、合并炎性疾病(类风湿性关节炎)、激素使用、术后拔引流管时间长(≥24 h)、肥胖是导致膝关节假体周围感染的危险因素。     

微创与传统手术入路在人工全髋关节置换术后临床疗效的Meta分析

目的系统比较微创手术入路与传统手术入路对于全髋关节置换术的临床疗效。方法计算机检索Pub Med、Embase、Cochrane等数据库(2005/01~2017/08)关于微创人工全髋关节置换术与传统全髋关节置换术后临床效果比较的随机对照试验(RCTs),两名研究者按照纳入与排除标准(初次全髋关节置换术临床随机对照研究)严格独立筛选文献并提取数据,另两名研究者应用Cochrane系统评价手册5.1.0版本偏倚风险评估标准评估文献质量。采用Review manager 5.2进行荟萃分析,系统比较两种术式的临床疗效差异(术后Harris髋关节功能评分、手术时间、术中出血量、住院时间、术后疼痛、术后并发症等和影像学指标)。结果共17篇文献、1 515人纳入研究。研究结果显示两组患者在术后HHS评分[WMD:0.17,95%CI(-1.00,1.34);P=0.11],手术时间[WMD:-2.50,95%CI(-6.74,1.73);P0.01],住院时间[WMD:-0.49,95%CI(-1.00,0.03);P=0.12]等方面差异无统计学意义,但微创组出血量少[WMD:-102.47,95%CI(-165.49,-39.45);P0.01],术后使用阿片类止痛药量更少[WMD=-6.79,95%CI(-12.30,-1.27);P=0.74]。两组在术后感染[RR=2.25,95%CI(0.70,7.22);P=0.17],脱位[RR=1.00,95%CI(0.29,3.41);P=1.00],周围神经损伤[RR=2.50,95%CI(0.49,12.72);P=0.27],无菌性松动[RR=1.67,95%CI(0.50,5.64);P=0.41],假体周围骨折[RR=0.90,95%CI(0.39,2.09);P=0.81],肺动脉梗塞[RR=1.00,95%CI(0.07,15.15);P=1.00],深静脉血栓[RR=0.93,95%CI(0.27,3.15);P=0.90]等并发症方面差异无统计学意义;两者在术中髋臼假体外展角安放失误率[RR=0.88,95%CI(0.59,1.31);P=0.51],髋臼假体前倾角安放失误率[RR=0.93,95%CI(0.52,1.68);P=0.81],股骨假体内外翻失误率[RR=0.81,95%CI(0.48,1.35);P=0.42]方面均差异无统计学意义。结论微创人工全髋关节置换术在术后HHS评分、手术时间、住院时间等方面无显著差异,但微创方式失血量少,术后使用镇痛药少;两者在术后并发症及术中假体安放准确率方面相当。纳入研究异质性较大,结果需要更多高质量的RCT进一步验证。     

终末期肾病患者骨折影响因素的Meta分析

目的 系统分析终末期肾病患者发生骨折的相关因素。方法 计算机检索中国知网、维普、万方、中国生物医学数据库、PubMed以及EMBASE中自建库以来公开发表的相关文献。由2名研究员独立筛选文献、提取资料、纳入文献质量评价,采用Review Manager 5.3软件进行统计分析。结果 共纳入19篇文献,合并结果提取8个相关影响因素,其中6个危险因素：年龄（OR=1.28, 95%CI:1.20～1.37, P<0.01）、女性（OR=1.93, 95%CI:1.51～2.46, P<0.01）、碱性磷酸酶（OR=1.03,95%CI:1.01～1.05,P=0.008）、甲状旁腺激素（OR=1.07,95%CI:1.04～1.10,P<0.01）、糖尿病（OR=1.70,95%CI:1.44～2.02,P<0.01）、透析年限（OR=1.83,95%CI:1.20～2.80,P=0.005）;2个保护因素：血清白蛋白（OR=0.81,95%CI:0.69～0.96,P=0.02）和活性维生素D3(OR=0.33,95%CI:0.16～0.67,P=0.002)。结...     

全髋关节置换术后翻修的原因分析

目的分析全髋关节置换术后行翻修手术的具体原因,并与以往文献报道的结果进行比较。方法回顾性分析自2014-01—2019-06完成的93例全髋关节翻修术,翻修术前均为初次单侧全髋关节置换术。将患者分为早期组(假体使用时间5年)和晚期组(假体使用时间≥5年),统计行翻修手术的原因,并对数据进行描述性分析。结果 45例(48.4%)全髋关节翻修原因为假体无菌性松动,19例(20.4%)为假体周围感染,15例(16.1%)为假体周围骨折,8例(8.6%)为聚乙烯内衬磨损,4例(4.3%)为髋关节反复脱位,髋关节疼痛、骨水泥游离体各1例。93例假体使用时间为(7.72±6.39)年,早期组38例,假体使用时间为(1.50±1.50)年;晚期组55例,假体使用时间为(12.02±5.09)年。早期组中13例假体周围感染,10例假体无菌性松动,9例假体周围骨折,4例髋关节反复脱位,1例聚乙烯内衬磨损,1例骨水泥游离。晚期组中35例假体无菌性松动,7例聚乙烯内衬磨损,6例假体周围感染,6例假体周围骨折,1例髋关节疼痛。结论假体无菌性松动是全髋关节置换术后最常见的翻修原因,随后依次为假体周围感染、假体周围骨折、聚乙烯内衬磨损、髋关节脱位等,这与国内外许多学者的研究一致。     

全髋关节置换术中假体周围骨折的研究进展

全髋关节置换术是一个较为成熟的手术,术中假体周围骨折是其并发症之一,假体周围骨折分为髋臼假体周围骨折和股骨假体周围骨折,危险因素包括微创技术的使用、压配式非骨水泥假体柄的使用、髋关节翻修术和骨质疏松等。本文就全髋关节置换术中假体周围骨折的分型及治疗进展进行综述。     

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 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.     

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.     

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.     

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.     

Is the recovery profile of mivacurium independent of the rate of decay of its plasma concentration in patients with normal plasma cholinesterase activity?

Background: The duration of action of muscle relaxants is poorly correlated to the rate of decay of their plasma concentration. The plasma concentration of mivacurium may rapidly decrease below its active concentration because of the extensive hydrolysis of mivacurium. By inflating a tourniquet on one upper limb for 3 min after the administration of atracurium, mivacurium or vecuronium, we studied the influence of the initial decline of their plasma concentration on their effect. Methods: In 50 patients anaesthetised with thiopental, isoflurane and fentanyl, the effect of bolus doses of 0.15 or 0.25 mg . kg^?1 mivacurium (MIV 15, MIV 25), 0.3 or 0.5 mg . kg^?1 atracurium (ATR 30, ATR 50) and 0.06 or 0.1 mg . kg^?1 vecuronium (VEC 06, VEC 10) were measured on both arms (evoked response of the adductor pollicis to train-of-four stimulation every 12 s), a tourniquet being applied on one arm just before and during 3 min after the muscle relaxant bolus. Results: Tourniquet inflation of 3 min almost abolished the neuromuscular effect of mivacurium. In the vecuronium groups and in the ATR 50 group, tourniquet inflation did not modify the maximum degree of depression of the twitch response. Also, the duration of action of vecuronium was unaffected by the tourniquet. In the ATR 30 group, times to return of the twitch response to 25% (duration 25%) and 75% (duration 75%) of control response were significantly shorter in the cuffed arm, 23 min vs 27 min, and 41 min vs 45 min, respectively. In the ATR 50 group, only duration 25% was significantly shorter in the cuffed arm (41 min vs 45 min). Conclusion: The results suggest that the rate of decline of the plasma concentration of mivacurium is so rapid, that a very low and almost clinically ineffective concentration is present as soon as 3 min after its administration. The results also indicate that the recovery from a mivacurium-induced neuromuscular blockade is not influenced by the rate of decay of its plasma concentration in patients with genotypically normal plasma cholinesterase.     

Membranes in Artificial Organs

Abstract: Membrane processes play a pivotal and enabling role in modern replacement therapy for acute and chronic organ failure and in the management of immunologic diseases. In fact, virtually all contemporary extracorporeal blood purification methods employ membrane devices, and the next generation of artificial organs and tissue engineering therapies are almost certain to be similarly grounded in membrane technology. In this short essay, we comment on the similarities and differences among synthetic membranes and their natural counterparts and also provide a critical overview of the demographics and technology of hemodialysis, hemofiltration, apheresis, oxygenation, and emerging membrane technologies and applications.     

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.