脊髓型颈椎病患者颈脊髓与椎管匹配关系和脊髓致压因素的动态变化分析

【摘要】 目的：观察脊髓型颈椎病（cervical spondylotic myelopathy,CSM）患者颈脊髓与颈椎管匹配关系的动态变化,分析脊髓椎管匹配关系及脊髓致压因素与脊髓受压风险的关系。方法：收集2018年1月~2021年7月在我院行颈椎动态磁共振成像（dynamic magnetic resonance imaging,DMRI）检查的CSM患者的影像学资料,排除图像不清晰、屈伸角度不理想者,共纳入63例患者,其中男37例,女26例;年龄50~67岁（56.6±4.9岁）。在DMRI横断面T2像上测量颈椎前屈、中立、后伸体位下C3~C7椎间盘水平脊髓面积及硬膜囊面积,计算脊髓与硬膜囊面积的比值（即椎管占有率）;横断面T2像上测量椎间盘突出程度,矢状面T2像上测量黄韧带厚度;横断面T2像上观察脊髓的受压程度,采用改良Muhle分级标准进行脊髓受压分级;观察椎间盘的退变程度,应用Pfirrmann分级标准进行评估。将所有观察节段分为椎间盘突出组及椎间盘非突出组进行比较,分析椎间盘突出是否影响脊髓椎管的匹配关系及黄韧带厚度变化。结果：共测量252个颈椎节段,其中C3/4椎间盘非突出节段33个,突出节段30个;C4/5非突出节段21个,突出节段42个;C5/6非突出节段17个,突出节段46个;C6/7非突出节段27个, 突出节段36个。椎间盘非突出组与突出组都满足脊髓横断面积后伸位>中立位>前屈位,硬膜囊面积前屈位>中立位>后伸位,椎管占有率后伸位>中立位>前屈位,差异均有统计学意义（P＜0.05）。椎间盘突出组中立位与非突出组前屈位、中立位C5/6椎管占有率在C3～C7四个节段中最高,差异均有统计学意义（P＜0.05）。椎间盘突出程度后伸位>中立位>前屈位,脊髓受压分级后伸位>中立位>前屈位,黄韧带的厚度后伸位>中立位>前屈位,差异有统计学意义（P＜0.05）;椎间盘突出组的椎间盘退变等级高于非突出组,差异有统计学意义（P＜0.05）。椎间盘突出组黄韧带较厚,与非突出组比较差异有统计学意义（P＜0.05）。结论：DMRI可显示CSM患者颈脊髓与椎管匹配关系的动态变化,颈椎由前屈位向后伸位运动时椎管占有率增高,脊髓受压风险增大,其中C5/6节段所受影响最明显。     

Bryan人工椎间盘置换术对颈椎曲度影响的研究

目的观察不同手术时期Bryan人工椎间盘置换术后置换节段脊柱功能单位（functional spine unit,FSU）曲度变化情况。方法随访2003年12月～2007年12月接受单节段Bryan人工椎间盘置换术的患者,在侧位X线片上测量FSU角度变化。结果 60例患者获得随访,随访3～69个月,平均32个月,手术节段包括C3/C4节段2例,C4/C5节段14例,C5/C6节段41例,C6/C7节段3例。术前FSU平均曲度为0.3°,末次随访时为-0.5°（P〈0.05）。根据手术日期将全部病例分成早期（2003～2004年）、中期（2005年）和后期（2006～2007年）3组,统计分析发现早期病例随访时FSU后凸平均增加1.6°,后期病例FSU后凸平均增加仅0.1°,2组的FSU角度变化差异有统计学意义（P〈0.05）。结论 Bryan人工颈椎椎间盘置换术术后FSU后凸主要发生在早期病例,通过经验的积累和手术技术的改进可以避免术后FSU后凸。     

人工颈椎间盘置换的疗效及其对相邻非责任节段失稳的影响

目的:观察相邻非责任节段失稳颈椎病患者Bryan人工颈椎间盘置换术后的临床疗效及失稳节段的影像学变化。方法:2005年7月～2009年1月在我院行Bryan人工颈椎间盘置换术且术后随访36个月以上的43例颈椎病患者中,9例术前存在置换相邻节段失稳,男4例,女5例;年龄26～43岁,平均33.5岁。术前JOA评分为7～13(10.16±3.17)分,颈痛VAS为1～7(4.3±2.7)分。术前均经颈椎正侧位与屈伸动力位X线片及颈椎MRI证实存在手术相邻节段影像学失稳,但为非责任节段。C4/5置换、C5/6失稳1例;C5/6置换4例,其中C4/5失稳3例,C6/7失稳1例;C6/7置换、C5/6失稳2例;双节段置换2例:C4/5、C5/6与C5/6、C6/7各1例,均为头端相邻节段失稳。术后1周及术后3、6、12、24、36个月行JOA评分、颈痛VAS评分及Odom评分评估手术临床疗效;术前及术后3、6、12、24、36个月在颈椎动力位X线片上测量置换节段、失稳节段、颈椎整体活动度(C2～C7)及颈椎曲度。结果:术后1周JOA评分、颈痛VAS评分与术前比较无统计学差异(P>0.05),术后3、6、12、24、36个月JOA评分、颈痛VAS评分较术前明显改善,差异有统计学意义(P<0.05)。术后1周和3个月时Odom评分均为优6例、良1例、可2例,优良率为77.8%;术后6个月优6例、良2例、可1例,优良率为88.9%;术后12、24及36个月,Odom评分均为优7例、良1例、可1例,优良率为88.9%。术后3、6、12个月置换节段、失稳节段的活动度和颈椎曲度与术前比较差异无统计学意义(P>0.05);术后24、36个月,失稳节段的活动度较术前明显减小(P<0.05),置换节段活动度及颈椎曲度较术前明显增大(P<0.05);术后各时间点C2～C7活动度较术前无统计学差异(P>0.05)。随访期间未发现假体松动、移位及下沉。结论:Bryan人工颈椎间盘置换治疗颈椎病的短中期临床疗效良好,能逐渐改善年轻颈椎病患者置换相邻节段的影像学失稳。     

经皮激光汽化颈椎间盘减压术的临床应用

目的评价经皮激光汽化椎间盘减压术（percutaneous laser disc decompression,PLDD）治疗颈椎间盘突出症的临床应用效果和应用前景。方法2003年3月-2005年12月,对47例颈椎间盘突出症患者96个椎间盘实施PLDD治疗。男25例,女22例;年龄37-72岁,平均56岁。突出椎间盘节段：单节段3例,多节段44例。C3、420个、C4、527个、C5、631个、C6、718个。通过激光对髓核组织的汽化,凝固减少髓核组织,降低椎间盘压力。激光汽化1次治疗3个椎间隙者5例,2个椎间隙者39例,1个椎间隙者3例。结果42例获随访3-31个月,平均13个月。疗效评价参考丁亮华等评定标准,优18例（42.9%）,良14例（33.3%）,中6例（14.3%）,差4例（9.5%）,有效率90.5%,优良率76.2%,无并发症发生。结论PLDD能有效缓解颈椎间盘突出症的症状和体征,创伤小、安全、有效。     

单节段ProDisc-C颈椎人工椎间盘置换术对颈椎曲度和活动度的影响

目的:观察单节段ProDisc-C颈椎人工椎间盘置换术后置换节段活动度和颈椎曲度变化情况,分析ProDisc-C人工椎间盘置换术的效果.方法:2006年6月～2008年9月对53例颈椎病患者行单节段前路减压、ProDisc-C人工椎间盘置换术,置换节段C3/4 7例,C4/5 10例,C5/6 27例,C6/7 9例.应用医学影像存储与传输系统(PACS)测量术前和末次随访时置换节段活动度(ROM)、置换节段脊柱功能单位(functional spinal unit,FSU)Cobb角和颈椎整体曲度(C2～C7 Cobb角).结果:随访3～36个月,平均13.8个月.术前置换节段ROM为8.60°±3.7°,末次随访时为9.7°±3.5°,有统计学差异(P<.05);术前PSU Cobb角(前凸为正值)为0.1°±4.8°,末次随访时为3.6°±4.5°,有统计学差异(P<.05);术前颈椎整体曲度为7.0°±10.2°,末次随访时为8.0°±10.4°,无统计学差异(P>.05).结论:单节段ProDisc-C颈椎人工椎间盘置换术后置换节段活动度较术前增大,颈椎整体曲度无明显变化,FSU前凸增大,对于术前病变节段FSU生理前凸变小或轻度后凸的拟行颈椎人工椎间盘置换的患者可选择ProDisc-C假体.     

人工髓核柔性稳定系统对犬邻近颈椎间盘影响的实验研究

目的：比较人工髓核柔性稳定一体化系统与钢板内固定系统置入对犬施术节段邻近颈椎间盘退变的影响。方法：选择健康杂种犬23只,雌雄不限,犬龄1.5～2.5岁,体重20.0～30.0kg。预实验组5只,测量犬颈椎间盘压力正常参考值。18只实验用犬随机分为人工髓核柔性稳定组（A组,9只）及钢板内固定组（B组,9只）,均经前路行C3/4椎间盘摘除、内置物置入手术。术中测量邻近颈椎间盘（C4/5）压力,并计算施术前后C4/5椎间盘压力差作为撑开压力,t检验比较A、B组间压力差有无显著性差异。术后6个月处死动物,行影像学（Pearce标准）及组织学观察,评价邻近上位颈椎间盘（C2/3）退变程度。结果：A、B组间施术前后邻近颈椎间盘（C4/5）压力差无显著性差异（P〉0.05）。术后6个月,B组动力位X线片发现C2/3有失稳表现者4例（44.4%）。MRIT2加权像C2/3椎间盘Pearce分级A组（平均1.78级）低于B组（平均3.22级）;A组C2/3椎间盘退变组织学分级（平均1.56级）亦低于B组（平均2.78级）,且差异均有显著性（P〈0.05）。各组内撑开压力与椎间盘退变分级呈正相关（P〈0.05）。结论：过高的撑开压力易导致犬施术节段邻近颈椎间盘退变,应用人工髓核柔性稳定系统较钢板固定可以有效防止邻近节段的退变。     

单开门椎管扩大椎板成形术保留一侧肌肉韧带复合体对颈后肌肉容积的影响

目的:评价单开门椎管扩大椎板成形术时保留一侧肌肉韧带复合体对颈后肌肉容积的影响。方法:对60例因脊髓型颈椎病行后路单开门椎管扩大椎板成形术的患者保留一侧(右侧)肌肉韧带复合体,其中男性41例,女性19例;年龄34~78岁,平均58.0岁;随访2.5~15个月,平均4.3个月,在术前和末次随访时均行颈椎MRI检查,在横断面MRI片上用Photoshop测量术前、末次随访时C2/3、C3/4、C4/5、C5/6、C6/7椎间盘水平左右两侧颈后肌肉的横截面积,以5个水平的总面积表示颈后肌肉的容积。对术前、末次随访时各个水平的左右侧颈后肌肉面积进行比较,并分别比较术前左侧与右侧总面积、末次随访时左侧与右侧总面积以及术前与末次随访时各单侧总面积的变化,用SPSS16.0对结果进行统计分析。结果:术前各个椎间盘水平左右侧颈后肌肉面积无显著性差异(P0.05),末次随访时C3/4、C4/5、C5/6水平右侧颈后肌肉面积明显大于左侧(P0.05),在C2/3、C6/7水平上左右侧颈后肌肉面积无显著性差异(P0.05)。右侧C2/3、C3/4、C4/5、C5/6水平颈后肌肉面积及右侧总面积的变化值(末次随访时-术前)与左侧相对应的变化值有显著性差异(P0.05);在C6/7水平上两者均无显著性差异(P0.05)。术前右侧颈后肌肉总面积与左侧比较无显著性差异(P0.05);末次随访时右侧颈后肌肉总面积明显大于左侧(P0.05)。结论:单开门椎管扩大椎板成形术保留一侧肌肉韧带复合体减少了对颈后方肌肉的破坏,在一定程度上保持了颈后肌肉的容积。     

连续双节段Bryan人工颈椎间盘置换术后异位骨化的长期研究

【摘要】 目的：对连续双节段Bryan人工颈椎间盘置换术后异位骨化的长期观察研究。方法：回顾性分析我科2004年1月~2011年12月行连续双节段人工颈椎间盘置换术的患者21例,其中男性15例,女性6例;年龄33~72岁,平均50.4±8.8岁。C3/4、C4/5间盘置换5例,C4/5、C5/6间盘置换14例,C5/6、C6/7间盘置换2例。随访时间96~156个月,平均随访116.5±19.6个月。记录患者术前、术后3个月及末次随访时改良日本骨科协会评分（modified Japanese Orthopaedic Association,mJOA）、视觉模拟评分法（visual analogue scale,VAS）评分,末次随访时在颈椎动力位X线片中测量人工颈椎间盘活动度,颈椎侧位X线片中测量颈椎曲度,采用McAfee分级法在颈椎侧位及动力位X线片上对人工颈椎间盘的异位骨化情况进行评估。结果：患者术前mJOA评分14.0±2.0分。术后3个月时mJOA评分15.2±1.8分,末次随访时mJOA评分16.8±1.2分,均较术前有统计学差异（P＜0.05）。术前VAS评分5.1±1.7分。术后3个月时VAS评分1.9±1.4分,末次随访时VAS评分0.9±0.8分,均较术前有统计学差异（P＜0.05）。术前颈椎曲度为平均16.7°±6.6°,末次随访时颈椎曲度为15.7°±7.3°,无统计学差异（P=0.25）。上位节段活动度为6.23°±10.13°,下位节段活动度为3.76°±4.81°,有统计学差异（P=0.025）。至末次随访时16例发生异位骨化,发生率为76.2%。根据McAfee分级,21例患者42个节段中,Ⅰ级5个节段,Ⅱ级5个节段,Ⅲ级14个节段,Ⅳ级7个节段,发生Ⅲ级以上HO的概率为50%,上位节段发生Ⅲ级和Ⅳ级HO的概率为38.0%,下位节段发生Ⅲ级和Ⅳ级HO的概率为61.9%。结论：长期随访发现行连续双节段Bryan人工颈椎间盘置换术后异位骨化发生率较高,且下位节段发生严重HO的概率明显增加。     

连续双节段Bryan人工颈椎间盘置换术后异位骨化的长期研究

【摘要】 目的：对连续双节段Bryan人工颈椎间盘置换术后异位骨化的长期观察研究。方法：回顾性分析我科2004年1月~2011年12月行连续双节段人工颈椎间盘置换术的患者21例，其中男性15例，女性6例；年龄33~72岁，平均50.4±8.8岁。C3/4、C4/5间盘置换5例，C4/5、C5/6间盘置换14例，C5/6、C6/7间盘置换2例。随访时间96~156个月，平均随访116.5±19.6个月。记录患者术前、术后3个月及末次随访时改良日本骨科协会评分（modified Japanese Orthopaedic Association，mJOA）、视觉模拟评分法（visual analogue scale，VAS）评分，末次随访时在颈椎动力位X线片中测量人工颈椎间盘活动度，颈椎侧位X线片中测量颈椎曲度，采用McAfee分级法在颈椎侧位及动力位X线片上对人工颈椎间盘的异位骨化情况进行评估。结果：患者术前mJOA评分14.0±2.0分。术后3个月时mJOA评分15.2±1.8分，末次随访时mJOA评分16.8±1.2分，均较术前有统计学差异（P＜0.05）。术前VAS评分5.1±1.7分。术后3个月时VAS评分1.9±1.4分，末次随访时VAS评分0.9±0.8分，均较术前有统计学差异（P＜0.05）。术前颈椎曲度为平均16.7°±6.6°，末次随访时颈椎曲度为15.7°±7.3°，无统计学差异（P=0.25）。上位节段活动度为6.23°±10.13°，下位节段活动度为3.76°±4.81°，有统计学差异（P=0.025）。至末次随访时16例发生异位骨化，发生率为76.2%。根据McAfee分级，21例患者42个节段中，Ⅰ级5个节段，Ⅱ级5个节段，Ⅲ级14个节段，Ⅳ级7个节段，发生Ⅲ级以上HO的概率为50%，上位节段发生Ⅲ级和Ⅳ级HO的概率为38.0%，下位节段发生Ⅲ级和Ⅳ级HO的概率为61.9%。结论：长期随访发现行连续双节段Bryan人工颈椎间盘置换术后异位骨化发生率较高，且下位节段发生严重HO的概率明显增加。     

经皮激光腰椎间盘减压术后腰椎关节突关节和椎间高度的变化

目的：观察经皮激光椎间盘减压术（percutaneous laser disc decompression，PLDD）治疗腰椎间盘突出症术后腰椎关节突关节和椎间高度的变化。方法：应用半导体激光系统对32例腰椎间盘突出症患者进行PLDD治疗。29例患者为单节段突出，其中L3/4 3例，L4／5 18例，L5/S1 8例；3例患者同时合并IA／5和L5/S1节段突出。利用Macnab标准评价随访患者的疗效，并观察术前、术后椎间盘突出节段关节突关节角的形态，测量L3，4、L4/5和L5／S1椎间高度指数和椎间盘突出节段关节突关节角的角度。结果：所有患者无术中和术后并发症。随访14～22个月，平均17个月，按Macnab标准评价：优14例（43．75％），良13例（40．63％）；可3例（9．37％），差2例（6．25％），优良率84．38％。术后L5/S1椎间高度指数与术前相比显著性下降（P〈0．05），但L3/4和L4／5椎间高度指数无显著性改变；关节突关节无明显退变；L4／5和L5／S1椎间盘突出侧的关节突关节角角度显著性下降（P〈0．05），但L3/4椎间盘突出侧的关节突关节角度无显著性改变。结论：经皮激光腰椎间盘减压术后患者的L5／S1椎间高度和腰椎间盘突出侧关节突关节角角度下降．有可能增加腰椎滑脱的风险。     

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.