腰椎终板Modic改变与腰椎间盘突出的相关性研究

[目的]探讨腰椎终板Modic改变与腰椎间盘突出的相关性及其意义.[方法]对628例患者(年龄14～85岁,平均50岁;男326例,女302例)腰椎MRI上L3、4～L5S1节段的Modic改变和腰椎间盘突出程度进行评估,统计两者的相关性.将单节段中、重度腰椎间盘突出者分为A组(仅该节段有Modic改变)和B组(任一节段均无Modic改变).统计两组下腰痛的发生率并采用疼痛视觉模拟评分(visual analogue scale,VAS)和Oswestry功能障碍指数评分(oswestry disability index,ODI)来评估腰痛程度.[结果]在1844个腰椎间盘中,椎间盘无突出组、轻度突出组、中度突出组和重度突出组Modic改变的发生率分别为6.83％、23.66％、42.72％和50.79％,差异有统计学意义(P＜0.01),Spearman相关检验表明Modic改变和腰椎间盘突出程度呈正相关(r=0.344,P＜0.01).A、B组下腰痛的发生率分别为59.32％和37.97％,差异有统计学意义(P＜0.01),但腰痛VAS评分和ODI评分差异无统计学意义(P＞0.05).[结论]腰椎终板Modic改变的发生与腰椎间盘突出程度呈正相关,当腰椎间盘突出合并Modic 改变特别是Ⅰ型改变时,下腰痛的发生率增加.     

腰椎退变性滑脱与终板Modic改变的相关性研究

目的 :观察腰椎退变性滑脱患者腰椎终板的Modic改变情况,分析退变性滑脱与终板Modic改变之间的关系。方法:回顾性分析108例腰椎退变性滑脱症患者的MRI资料,观察腰椎滑脱节段与非滑脱节段终板Modic改变各型的发生率及分布情况,分析终板Modic改变与腰椎滑脱的相关性。结果:108例腰椎退变性滑脱患者共540个椎体中,Ⅰ度滑脱149个,Ⅱ度滑脱17个;L1椎体滑脱10个,L2椎体26个,L3椎体41个,L4椎体46个,L5椎体43个。108例腰椎退变性滑脱患者共计1080个腰椎终板,351个终板存在Modic改变,其中ModicⅠ型172个(15.93%),Ⅱ型144个(13.33%),Ⅲ型3个(0.28%),混合型32个(2.96%);L1/2节段34个(3.15%),L2/3节段61个(5.65%),L3/4节段65个(6.02%),L4/5节段77个(7.13%),L5/S1节段114个(10.56%)。腰椎滑脱节段终板的Modic改变发生率为75.30%,非滑脱节段终板的Modic改变发生率为13.50%,差异有统计学意义(P0.05)。Spearman相关检验表明Modic改变和腰椎滑脱程度呈正相关(r=0.613,P0.05)。结论 :腰椎退变性滑脱患者滑脱节段终板的Modic改变多见,各型中以Ⅰ型多发,Modic改变的发生与滑脱程度呈正相关。     

腰腿痛患者腰椎MRI椎间盘相邻终板Modic改变分布情况及相关机制

目的观察腰腿痛患者腰椎MRI椎间盘相邻终板Modic改变分布情况,并探讨与腰腿痛发生的相关机制。方法选择200例腰腿痛患者,均进行常规X线片以及腰椎磁共振(MRI)检查,共检查1000个椎间盘,观察所有患者腰椎终板Modic改变发生情况、改变类型及分布特点。根据患者腰椎稳定情况分为稳定组与不稳定组,分析其与Modic改变的关系;根据腰椎曲度情况将腰椎稳定者分为正常组与异常组,分析其与Modic改变的关系。结果 200例腰腿痛患者发生Modic改变58例,发生率29.00%,发生Modic改变的椎间盘82个,发生率8.20%。伸屈位X线片显示腰椎稳定94例,腰椎不稳定106例,稳定组Modic改变率为20.21%,显著低于不稳定组的59.43%,差异有统计学意义(P0.05);腰椎稳定组腰椎曲度正常32例,腰椎曲度异常62例,腰椎曲度正常组Modic改变率12.50%,显著低于异常组的24.19%,差异有统计学意义(P0.05)。结论腰腿痛患者椎间盘相邻终板Modic改变发生率较高,以ModicⅡ型改变为主,L_(4-5)、L_5-S_1节段发生率较高,Modic改变可能与腰椎不稳和腰椎曲度异常有关。     

腰椎Modic改变对腰椎间盘突出症患者术后症状的影响

目的探讨腰椎终板Modic改变对椎板间开窗椎间盘摘除术术后腰腿痛的影响。方法 2009年7月至2011年8月,我院采用椎板间开窗椎间盘摘除术治疗单节段腰椎间盘突出症患者114例,男45例,女69例;平均年龄48岁(28~69岁);L4~5突出43例,L5S1突出71例。根据有无终板改变分为A、B两组。A组:MRI影像显示终板有信号改变,共50例,其中ModicⅠ、Ⅱ、Ⅲ型分别为11例、35例、3例(其余1例为混合型);B组:MRI影像示终板无信号改变,共64例。分别记录术前和末次随访时的VAS、ODI值及腰腿痛的术后复发率,并进行统计学分析。结果本组平均随访14个月(4~27个月)术前A、B组的VAS、ODI值差异无统计学意义(P0.05)。A组术后腰痛VAS值、腿痛VAS值、ODI值改善率分别为75.6%、89.2%、79.2%,B组分别为86.4%、90.6%、87.3%。A组腰痛VAS值及ODI值改善率与B组比较差异有统计学意义(P0.05),但A、B组腿痛VAS值改善率差异无统计学意义(P0.05)。术后不同类型Modic改变的腰痛VAS值、腿痛VAS值及ODI值改善率之间差异无统计学意义(P0.05)。A组术后腰腿痛的复发率高于B组。结论椎板间开窗椎间盘摘除术能显著减轻椎间盘突出患者腰腿痛症状,对与伴有终板Modic改变的椎间盘突出患者,术后腰痛的缓解程度较无Modic改变者差,但腰腿痛复发率高,其可能原因之一是未处理发生Modic改变的终板。     

中老年腰腿痛患者腰椎终板Modic改变的分布情况及其与腰椎不稳的关系

目的:探讨中老年腰腿痛患者腰椎终板Modic改变的分布情况,分析其与腰椎不稳之间的关系。方法:随机选取2007年3月~2011年12月因腰腿痛在我院行腰椎MRI和常规X线片检查的年龄≥40岁的患者430例,男210例,女220例,年龄40~73岁。观察患者腰椎终板Modic改变的发生率、类型及分布特点;根据腰椎是否稳定分为腰椎稳定组和腰椎不稳定组,分析其与Modic改变之间的关系;腰椎稳定组患者分为腰椎曲度正常组和异常组,分析其与Modic改变之间的关系。结果:430例共计2150个腰椎椎间盘中,124例(28.84%)154个(7.16%)椎间盘终板存在Modic改变,其中Ⅰ型34例(7.91%)、34个椎间盘(1.58%),Ⅱ型72例(16.74%)、100个椎间盘(4.65%),Ⅲ型18例(4.19%)、20个椎间盘(0.93%);L2/3 14个,L3/4 24个,L4/5 50个,L5/S1 66个,其发生率分别为0.65%、1.12%、2.32%、3.07%;其中Modic改变位于终板前部79个,后部31个,整个终板44个;仅累及上终板52个,仅累及下终板41个,累及上、下终板61个。腰椎不稳定组终板Modic改变的发生率为36.68%,腰椎稳定组为19.90%,两组差异有统计学意义(P<0.05);ModicⅠ、Ⅱ、Ⅲ型中腰椎不稳的发生率分别为82.35%、69.44%、33.33%,三者差异有统计学意义(P<0.05);腰椎曲度正常组终板Modic改变的发生率为11.11%,腰椎曲度异常组为23.91%,两组差异有统计学意义(P<0.05)。结论:中老年腰腿痛患者腰椎终板Modic改变以Ⅱ型最多见,以L4/5和L5/S1节段多发;其与腰椎不稳和腰椎曲度之间存在相关关系,ModicⅠ型改变与腰椎不稳相关性最强。     

腰椎终板Modic退变对手术疗效影响的远期观察

[目的]探讨腰椎终板Modic退变对伴有下腰痛的腰椎间盘突出症患者手术疗效的远期影响.[方法]回顾分析50例行腰椎单阶段开窗减压髓核摘除术的腰椎间盘突出症患者,分为两组,一组有腰椎终板Modic退变(A组),另一组无腰椎终板Modic退变(B组).对其随访至少48个月,比较两组患者术后临床疗效,并评价腰椎终板Modic退变对患者术后下腰痛缓解的影响.[结果]术后两组患者坐骨神经痛症状均缓解.临床疗效优良率:A组90.48%;B组93.10%,两组比较差异无统计学意义(P>0.05).术后VAS评分:A组21.37±7.59;B组8.34 ±3.78,两组比较差异有统计学意义(P<0.05).[结论]腰椎问盘突出症患者术后下腰痛恢复情况与腰椎终板Modic退变相关,提示腰椎终板Modic退变可能是下腰痛的原因之一,对终板的观察可以更全面的评判下腰痛的发生、预后.     

腰椎终板Modic改变与腰椎退变的相关性研究

目的总结腰椎终板Modic改变的临床分布特点,探讨Modic改变的发生与腰椎退行性变的相关性。方法对腰腿痛就诊的348例患者根据Modic分级标准对患者腰椎矢状位MRI资料进行评估,记录有无Modic改变、腰椎管狭窄、腰椎滑脱、椎间盘退变,并通过X线测定椎间隙高度。使用SPSS 18.0统计学软件对数据进行处理,探讨Modic改变的发生与性别、年龄、腰椎节段、间盘膨出、间盘突出、间盘脱出、椎间隙改变、椎管狭窄、腰椎滑脱的相关性。结果 348例共1 740个腰椎椎间盘中,89例(25.6%,包括手术患者7例)139个椎间盘(7.9%)邻近终板发生Modic改变,以Ⅱ型为多。按性别统计:男女差异无统计学意义;按不同年龄组统计:50~59岁组最多,为34.31%;Modic改变在椎间盘突出或脱出者、椎间隙高度降低者、退行性腰椎管狭窄、腰椎Ⅰ度滑脱者的发生率较高。结论腰椎终板存在Modic改变,最常见的类型为Ⅱ型,Ⅰ型次之,Ⅲ型最为少见,其多发生于L5~S1节段,其次为L4~5。腰椎Modic的发生与年龄、腰椎节段、间盘膨出、间盘突出、间盘脱出、椎间隙改变、椎管狭窄、腰椎滑脱存在相关性。Modic改变可能是腰椎间盘退变严重的表现。     

腰椎间盘退变性疾患下腰椎终板形态的MRI观察

【摘要】　目的：在MRI片上观察腰椎间盘退变患者下腰椎终板形态的分布规律,分析终板形态和椎间盘退变的关系。方法：回顾分析两组腰椎间盘退变性疾病患者的术前腰椎MRI,A组110例为单节段腰椎间盘突出症患者,B组35例为椎间盘源性腰痛患者。根据正中矢状面MRI T1像,将终板形态分为凹面、平坦、不规则三型;根据Pfirrmann法评定椎间盘退变程度并将Ⅰ～Ⅴ级分别计为1～5分;按Modic改变分级标准判定各节段终板有无Modic改变。分析下腰椎终板的形态特点及三种分型与椎间盘退变程度、Modic改变等的关系。结果：①435个下腰椎节段中,凹面型终板最多（215/435）,A组中占50.6％（167/330）,B组中占45.7％（48/105）,且主要分布于L3/4（108/215）、L4/5（83/215）节段;平坦型终板占29.0％（126/435）,并主要位于L5/S1节段（76/126）;不规则型终板最少（94/435）,A组中占23.0％（76/330）,B组中占17.1％（18/105）,也主要位于L5/S1节段（45/94）。②A组患者中,凹面型终板退变程度平均为3.31±0.81分,平坦型为3.66±0.64分,不规则型为4.16±0.67分,两两比较有显著差异（P＜0.05）;椎间盘突出节段以平坦型（37/110）和不规则型（43/110）终板占多数,无突出节段则以凹面型（137/220）终板占多数,差异有显著性（P＜0.05）;不规则型终板比凹面型和平坦型更容易伴发Modic改变,差异有显著性（P＜0.05）,凹面型和平坦型间无显著性差异（P＞0.05）。③B组患者中,凹面型终板的椎间盘退变程度平均为3.23±0.86分,平坦型为3.54±0.85分,不规则型为3.94±0.54分,仅凹面型和不规则型间差异有显著性（P＜0.05）。④相同终板形态时A组和B组椎间盘退变程度相比均无显著性差异（P＞0.05）。结论：终板形态与椎间盘退变、Modic改变之间有相关性。终板形态由凹面型到平坦型再到不规则型,腰椎间盘退变程度逐渐加重。影像学上终板形态改变在一定程度上反映了椎间盘退变的程度。     

腰椎终板Modic改变的影响因素及临床治疗进展

<正>椎体软骨终板分为骨性终板和软骨终板,其作用非常重要,对维持脊柱的整体以及椎间盘的功能有重要的意义,研究表明终板的生物力学和生物化学特性的改变容易引起椎间盘退变相关疾病[1~3]。腰椎终板及终板下骨质在MRI上的信号改变被称为Modic改变,其发生率正常人群中为6%,腰背痛人群中为40%[4],Modic改变在中年会进     

退变性腰椎侧凸椎体终板Modic改变的分布情况及其影响因素

目的:观察退变性腰椎侧凸患者终板Modic改变的分布情况,分析其相关影响因素及与腰痛的关系。方法:回顾分析2000年3月～2009年3月我院收治的126例退变性腰椎侧凸患者的影像学资料,采用VAS对患者腰痛程度进行评估。观察患者终板Modic改变的发生率、类型及分布特点;比较存在Modic改变与不存在Modic改变患者的VAS评分;分析Modic改变与椎间盘退变、终板倾斜度、腰椎侧凸角及体重指数间的相关性。结果:126例患者756个腰椎间盘中,69例(54.8%)124(18.2%)个椎间盘邻近终板存在Modic改变。存在Modic改变患者VAS评分5.5±2.0,不存在Modic改变患者VAS评分3.0±1.5,两者比较差异有显著性(P<0.01)。Modic分型:Ⅰ型有15例患者(11.9%)19个椎间盘退变(2.5%),Ⅱ型48例(38.1%)97个椎间盘退变(12.8%),Ⅲ型6例(4.8%)8个椎间盘退变(1.1%)。退变终板节段:L5/S1椎间盘32个(25.8%),L4/5椎间盘26个(21.0%),L3/4椎间盘9个(7.3%),L2/3椎间盘47个(37.9%),L1/2椎间盘6个(4.8%),T12/L1椎间盘4个(3.2%)。Modic改变发生于终板凹侧99(13.1%)个,发生于终板凸侧25(3.3%)个;凹侧与凸侧发生率比较差异有显著性(P<0.01)。Modic改变与椎间盘退变、终板倾斜度、腰椎侧凸角及体重指数存在显著相关性(P<0.05)。结论:Modic改变与椎间盘退变、终板倾斜度、腰椎侧凸角及体重指数之间存在相关关系;Modic改变以Ⅱ型多见,多发生于终板的凹侧,以L2/3、L5/S1和L4/5节段多发。     

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.