压力波形联合回流液相指导各节段硬膜外定位的效果

硬膜外穿刺技术是麻醉与镇痛的重要手段,而临床上硬膜外穿刺置管仍普遍采用盲探性操作方法,依靠主观经验评判.即使采用硬膜外穿刺置管定位的辅助方法如超声、硬膜外造影等,临床实用性也较差[1-6].本研究拟评价硬膜外穿刺过程中压力波形联合回流液相指导各节段硬膜外定位的效果,为建立可靠、易行的辅助方法提供参考.     

压力波形联合回流液相双指征监测法定位硬膜外麻醉的临床应用

背景 硬膜外穿刺技术临床上广泛用于颈部、胸腹部、下肢手术的麻醉与疼痛治疗.现行传统硬膜外麻醉操作为一种盲探性穿刺置管技术,单独依靠操作者的感觉和经验及简单的试验方法评判麻醉成功与否,难以做到精确可控,而麻醉状态无客观指征监测,麻醉失败原因常无法得知.目的 为改进现行盲探方法,探求硬膜外麻醉的可视化指征的可行性.内容 自2006年以来,经不断深入研究,以“压力波形联合回流液相双指征法”用于辅助硬膜外麻醉,达到了可视化指征,辅助硬膜外麻醉定位与监测,效果理想.至今已在临床成功应用万例以上(内蒙古医学院附属医院完成硬膜外麻醉1万余例/年,约占麻醉总例数的50％).趋向 目前此项技术已常规应用于临床并加以推广,现予以介绍,以期建立新型硬膜外麻醉操作流程,从而使麻醉全程达到严谨、规范、安全、可靠,进一步提高硬膜外麻醉的安全有效性.     

胆囊切除术病人超声引导硬膜外穿刺的效果

硬膜外麻醉效果与硬膜外导管的位置关系密切.硬膜外穿刺常以体表标志和阻力消失技术(LOR)定位,其成功主要依赖于操作者的经验,失败率2%～3%.改良的高分辨率便携式超声设备,为超声引导区域神经阻滞提供了条件.本研究拟评价胆囊切除术病人超声引导硬膜外穿刺的效果.     

压力波形监测在硬膜外麻醉穿刺置管中的研究进展

在传统盲探穿刺的基础上,近年来提出一种新的压力波形监测方法用于硬膜外麻醉。相比较于临床普遍采用的阻力消失法以及超声引导、计算机断层扫描、介入造影等新兴的辅助硬膜外麻醉的穿刺方法,大量研究表明压力波形监测方法可作为硬膜外麻醉穿刺成功的客观指征,可全程实时监测硬膜外麻醉过程,安全可靠,简便实用。文章回顾压力波形监测方法在硬膜外麻醉应用的原理,对硬膜外麻醉穿刺置管过程中的压力波形特点及其临床应用进行综述。压力波形监测方法为硬膜外麻醉提供了一种简单的辅助手段,可以区分阻力消失法的真阳性和假阳性。     

超声实时引导在肥胖患者腰段硬膜外麻醉中的临床应用

目的探讨超声实时引导技术在肥胖患者腰段硬膜外麻醉中的临床应用。方法 86例患者随机分为超声实时引导组(超声组)和传统定位盲探穿刺组(对照组),每组43例。超声组采用超声实时引导进行硬膜外穿刺置管;对照组采用传统的体表解剖标志进针及阻力消失法确定硬膜外间隙。记录两组麻醉前准备时间、穿刺时间、穿刺次数、术中麻醉效果及术后腰痛发生率,超声测量的硬膜外腔的深度与实际穿刺时进针深度。结果两组均成功实施硬膜外穿刺,麻醉效果均能满足手术需要。与对照组比较,超声组穿刺时间明显缩短(P<0.01),穿刺次数明显减少(P<0.05),术后腰痛发生率明显降低(P<0.05)。超声测量的硬膜外腔的深度与实际穿刺时进针深度存在显著正相关关系(r=0.861,P<0.01)。结论超声实时引导技术能提高肥胖患者硬膜外麻醉的质量和满意度,同时避免误伤周围组织,降低术后腰痛发生率,值得在临床推广应用。     

硬膜外导管可疑误入硬膜外静脉引起局麻药毒性反应6例报道

硬膜外阻滞是中下腹部、盆腔及下肢手术常用的麻醉方法之一。但是硬膜外穿刺及置管时有误人硬膜外静脉的可能,有时未能发现注入局麻药后,致使短时间内血液中局麻药浓度骤升,立即发生毒性反应。现将我院遇到此种意外及其临床症状和处理报道如下。     

采用造影技术对硬膜外阻滞效果的临床观察

我们采用非离子型造影剂硬膜外腔造影与麻醉同步技术,对40例患者进行了硬膜外腔置管阻滞前后的造影对比,观察了非离子型造影剂在硬膜外腔的显影情况、导管位置、解剖结构及麻醉效果和对其影响因素,现总结如下: 资料和方法随机选择40例适合于硬膜外阻滞手术的病人,其中男19例,女21例,年龄5～74岁,平均38.5岁。在电视监视下,使用相同规格的硬膜外导管,导管腔容积为0.3ml,病人均取右侧卧位直入法穿刺,头向置管35例、尾向置管5     

90例硬膜外腔置管后的X线定位分析

在硬膜外麻醉中,常把置管长度和方向也作为调整阻滞范围的一种手段。导管在硬膜外腔内的位置究竟如何?置管长度和方向对其究竟有何影响?我们对此进行了 X 线定位分析。临床资料本组共90例,男65,女25,年龄14～64岁,均为硬膜外麻醉下拟行外科手术的病人。穿刺点选胸段15例,腰段75例。穿刺时左侧卧位71例,右侧卧位19例。均采用直入法,以突破感、负压和气泡外溢等作为穿刺针进入     

膀胱截石位致腓总神经损伤1例报告

患者女,71岁。因膀胱肿瘤于2008年3月行经尿道膀胱肿瘤电切术。采用连续硬膜外联合闭孔神经阻滞,硬膜外麻醉经L3～4穿刺,向尾侧置管3.5cm。穿刺与置管过程顺利,无异感及出血。试验剂量2%利多卡因4mL。     

置管前后注药进行硬膜外阻滞的临床比较

硬膜外阻滞是我国临床麻醉的最主要麻醉方法之一。为了探索置管前、后注药对硬膜外阻滞效果及血压的影响,我们选择了上腹部手术80例进行了观察,现将结果报告如下。     

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.     

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.     

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.     

Dilemma of Membrane Biocompatibility and Reuse

Abstract: Numerous articles have been published on the multiple use of dialyzers and on the effect of different reprocessing chemicals and techniques on the dialyzer biocompatibility and performance. The results often appear contradictory, especially those comparing standard biocompatibility parameters. Despite this confusion, a discerning review of the published works allows certain limited conclusions to be drawn. Reprocessing of used hemodialyzers changes the biocompatibility profile of a dialyzer as defined by the parameters complement activation. leukopenia, and cytokine release. The effect of reprocessing depends on the chemicals and reprocessing technique applied and also on the type of membrane polymer being subjected to the reprocessing procedure. Reports of pyrogenic reactions indicate that the flux of the membrane also influences how suitable it is for safe reuse. An increased risk of allergic and pyrogenic reactions appears to be associated with dialyzer reuse. Furthermore, there has been a lack of investigations into the immunologic effect of the layer of adsorbed and chemically altered proteins that remains on the inner surface of reprocessed dialyzers. We conclude that the clinical benefit of dialyzer reuse cannot be generally accepted from a biocompatibility point of view.