中空双头螺纹加压钉治疗儿童股骨颈骨折

目的探讨中空双头螺纹加压钉治疗儿童股骨颈骨折的疗效。方法采用中空双头螺纹加压钉治疗儿童股骨颈骨折18例,与采用多根骨圆针治疗该骨折的20例进行疗效对比。结果随访2～5年,平均3.2年,螺纹加压钉组3个月骨折愈合率明显高于骨圆针组(P<0.01),关节疼痛及跛行螺纹加压钉组低于骨圆针组(P<0.05),股骨头缺血坏死例数螺纹加压钉组明显少于骨圆针组(P<0.01)。结论中空双头螺纹加压钉是治疗儿童股骨颈骨折的有效方法,优于多根骨圆针内固定。     

双头空心加压螺钉经皮固定治疗股骨颈骨折

目的　探索双头加压螺钉经皮固定治疗股骨颈骨折的临床效果。方法　C形臂X线机透视下 ,手法复位股骨颈骨折后 ,经皮穿置直径 2mm骨圆针 4～ 6根预固定 ,选用股骨颈轴线上下的三枚骨针作为导针 ,引导旋入直径为 5mm双头加压螺纹钉3枚 ,治疗股骨颈骨折 5 7例 ,术后随访 2～ 5年 ,对其临床功能、X线片、CT等作总结分析。结果　功能正常或轻度受限者47例 ,占 86 2 % ,骨折愈合 5 3例 ,占 92 7% ,股骨头坏死 6例 ,占 10 5 %。骨折不愈合并股骨头坏死者 1例 ,术后 3年 2个月 ,仍有良好的功能。结论　空心双头加压螺纹钉经皮固定股骨颈骨折 ,方法简单 ,固定可靠 ,治疗效果好 ,适合治疗各型股骨颈骨折     

股骨颈骨折闭合复位、三枚双头空心加压螺钉内固定术

为探讨股骨颈骨折闭合复位、三枚双头空心加压螺钉内固定术的疗效,39例股骨颈骨折按Garden分型:Ⅱ型6例、Ⅲ型24例、Ⅳ型9例,全部采用闭合复位、三枚双头加压空心螺钉内固定.平均随访时间25(6～42)个月,骨折不连接及股骨头缺血坏死占10.3%,功能恢复优良率89.7%.股骨颈骨折闭合复位内固定的关键是维持良好对位状态下的有效固定,三枚双头加压螺钉固定方法能有效地防止骨折端间的旋转、分离、剪切错位,有利于骨折愈合,并且操作简便,创伤小,是一种较为理想的固定方法.     

双头空心加压螺钉经皮固定治疗股骨颈骨折

目的：探索双头加压螺钉经皮固定治疗股骨颈骨折的临床效果。方法：C形臂X线机透视下,手法复位股骨颈骨折后,经皮穿置直径2mm骨圆针4－6根预固定,选用股骨颈轴线上的三枚骨针作为导针,引导旋入直径为5mm双头加压螺纹钉3枚,治疗股骨颈骨折57例,术后随访2－5年,对其临床功能、X线片、CT等作总结分析。结果：功能正常或度受限者47例,占86．2％,骨折愈合53例,占92．7％,肌骨头坏死6例,占10．5％。骨折不愈合并股骨头坏死者1例,术后3年2个月,仍有良好的功能。结论：空心双头加压螺纹钉经皮固定股骨颈骨折,方法简单,固定可靠,治疗效果好,适合治疗各型股骨颈骨折。     

多枚加压螺纹钉内固定治疗老年人股骨颈骨折的疗效分析

目的探讨应用多枚加压螺纹钉内固定治疗老年人股骨颈骨折的疗效。方法回顾性分析2000年1月～2004年2月应用多枚加压螺纹钉治疗58例老年股骨颈骨折患者的临床资料。按Garden分类:Ⅰ型3例,Ⅱ型18例,Ⅲ型26例,Ⅳ型11例。结果平均手术时间为55min,术中平均出血量为150mL。58例患者获1～4年(平均2.5年)随访。53例患者骨折愈合,3例患者出现股骨头坏死,2例患者骨折不愈合。功能评定按Harris评分标准:优38例,良14例,可2例,差4例,优良率为89.7%。结论多枚加压螺纹钉内固定治疗老年人股骨颈骨折具有良好的固定效果,符合生物力学观点,其操作简便、创伤小、愈合率高、并发症少、可以早期功能锻炼,有利于降低骨折的不愈合率和股骨头缺血性坏死的复发率,是治疗老年人股骨颈骨折的良好方法。     

三根中空双头螺纹加压钉经皮固定治疗股骨颈骨折

目的：总结三根中空双头螺纹加压钉经皮固定治疗股骨颈骨折的效果，并分析其特点。方法：自1993年～2000年，在“C”形臂X线机监视下，以Mc-Elvenny法行骨折复位，应用三枚中空双头螺纹加压钉经皮固定治疗股骨颈骨折42例。结果：股骨颈骨折愈合率达90％(38／42)。35例获得优良的功能，7例发展为股骨头坏死。无其他严重并发症。结论：中空双头螺纹加压钉经皮固定治疗股骨颈骨折疗效可靠，操作简单，有很高的骨折愈合率，创伤小、螺钉不易松动、退出，感染机会少。     

加压空心螺纹钉内固定加股方肌骨瓣移植治疗中青年股骨颈骨折

目的探讨中青年股骨颈骨折的治疗方法和临床治疗效果。方法自1998年1月~2004年12月收治中青年股骨颈骨折58例,其中GardenⅠ、Ⅱ型25例,GardenⅢ、Ⅳ型33例,采用3枚加压空心螺纹钉内固定加股方肌骨瓣转位移植治疗。结果所有病例均获随访,随访时间13~48个月,平均35个月。骨折全部愈合,愈合时间3~8个月,平均5个月,骨折愈合率100%,功能优良率91.4%;髋内翻2例,股骨头坏死2例。结论3枚加压空心螺纹钉内固定加股方肌骨瓣移植治疗中青年股骨颈骨折具有愈合时间短、骨折愈合率和功能优良率高等优点,是治疗中青年股骨颈骨折一种理想的方法。     

中空双头螺纹加压钉治疗股骨颈骨折的生物力学测试与临床应用

探讨中空双头螺纹加压钉固定股骨颈骨折的生物力学性能与临床效果。利用9具成年新鲜股骨尸体标本,分别采用中空双头螺纹加压钉、实心螺纹钉、三翼钉进行股骨颈骨折内固定,并进行生物力学实验。三枚中空双头螺纹加压钉比三枚实心螺纹钉、三翼钉在抗压、抗弯、抗扭强度和刚度上占有一定的优势。统计结果显示,具有显著性差异(P<0.01)。临床22例实践证明,这种内固定方法能加速骨折愈合,功能恢复较快。中空双头螺纹加压钉是治疗股骨颈骨折理想的内固定器械,符合生物力学特性。     

闭合复位空心螺纹钉内固定治疗股骨颈骨折效果观察

目的探讨采用闭合复位空心螺纹钉内固定治疗股骨颈骨折的疗效。方法对59例股骨颈骨折患者采用闭合复位空心螺纹钉内固定治疗,观察手术时间、骨折愈合情况和股骨头缺血性坏死发生率。结果本组患者手术时间平均40.3 min。均获随访时间平均36.3个月,未出现泌尿系统感染、肺部感染、压疮和下肢深静脉血栓形成。本组7例(11.86%)骨折愈合不佳。12例(20.34%)发生股骨头缺血性坏死。结论股骨颈骨折患者采用闭合复位空心螺纹钉内固定治疗疗效确切,可促进骨折愈合,减少并发症。     

小切口复位加压螺钉固定治疗股骨颈骨折

目的观察空心加压螺钉治疗股骨颈骨折的临床疗效。方法股骨颈骨折42例,在麻醉下行小切口复位,两枚空心加压螺钉内固定手术。观察疗效及愈合情况。结果术后42例经2 a以上随访,按照梁雨田等制定的疗效标准:优23例,良12例,可5例,差2例,优良率为83.3%;坏死2例,坏死率4.8%,骨折不愈合3例,占7.1%。骨折平均愈合时间为半年。结论使用两枚空心加压螺钉固定牢固,减少股骨颈切割,能明显促进股骨颈骨折的愈合,降低股骨头坏死及骨折不愈合等并发症。     

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.