3D打印导板辅助经皮椎间孔镜下腰椎间盘切除术的临床应用效果

目的 探讨3D打印导板辅助经皮椎间孔镜下腰椎间盘切除术（PELD）治疗腰椎间盘突出症（LDH）的临床效果。方法 选取2020年8月至2021年8月在我院采用PELD治疗单节段LDH的48例病人，根据是否采用3D打印导板辅助手术分为导板组和对照组。导板组24例，采用3D打印导板辅助下穿刺行PELD治疗，对照组24例，采用单纯PELD治疗。比较两组的手术时间、术中出血量、穿刺次数、穿刺时间、透视次数、住院时间，比较两组在术前及术后不同时间的疼痛视觉模拟量表（VAS）评分、日本骨科协会（JOA）评分、改良MacNab疗效评价和术后并发症发生率。结果 病人随访（9.33±1.24）个月（7~12个月）。导板组病人的手术时间、术中出血量、穿刺次数、穿刺时间、透视次数及住院时间均明显低于对照组，差异有统计学意义（P＜0.05）。两组术后VAS评分均低于术前，差异有统计学意义（P＜0.05）；导板组在术后1天、1周时的VAS评分低于对照组，差异有统计学意义（P＜0.05）；但两组术后1个月、3个月的VAS评分比较，差异无统计学意义（P＞0.05）。两组术后JOA评分均较术前明显升高，差异有统计学意义（P＜0.05）；但组间各时间段的JOA评分比较，差异无统计学意义（P＞0.05）。两组末次随访改良MacNab标准的优良率、并发症发生率比较，差异均无统计学意义（P＞0.05）。结论 通过3D打印导板辅助PELD治疗单节段LDH，手术效果确切，明显提高了穿刺准确性，减少了因反复穿刺而带来的手术创伤及辐射伤害，提高了手术效率、缩短了手术时间，对术后短期内疼痛的缓解作用显著，具有良好的临床使用前景。     

计算机导航技术辅助定位穿刺行经椎间孔入路经皮内窥镜下椎间盘切除术

目的 比较计算机导航技术辅助定位穿刺和常规定位穿刺行经椎间孔入路经皮内窥镜下椎间盘切除术（PETD）治疗腰椎椎间盘突出症（LDH）的临床疗效。方法 2018年10月—2019年4月,贵港市人民医院采用PETD治疗LDH患者70例,根据穿刺方法分为计算机导航辅助定位穿刺组（导航组）和常规定位穿刺组（常规组）,每组35例。记录并比较2组手术时间、透视时间、透视次数、穿刺时间、穿刺次数及并发症发生情况。采用疼痛视觉模拟量表（VAS）评分评估2组患者腰部及下肢疼痛情况,采用日本骨科学会（JOA）评分和Oswestry功能障碍指数（ODI）评估术后功能恢复情况。结果 所有手术顺利完成。导航组手术时间、透视时间、透视次数、穿刺时间、穿刺次数均少于常规组,差异有统计学意义（P < 0.05）。2组术后腰痛VAS评分、下肢痛VAS评分、JOA评分及ODI均较术前显著改善,差异有统计学意义（P < 0.05）,组间比较差异无统计学意义（P > 0.05）。导航组术后出现LDH复发2例、脱出椎间盘残留2例,常规组术后出现LDH复发2例、脱出椎间盘残留4例,根据严重程度行非手术或再次手术治疗后症状均缓解。Pearson相关分析显示,透视次数、透视时间、穿刺次数、穿刺时间及手术时间之间存在高度相关性。结论 计算机导航技术辅助定位穿刺行PETD可减少透视和穿刺的次数和时间,进而减少手术时间及降低医患的辐射暴露,值得临床推广。     

骨科机器人辅助微创精准手术治疗胸腰段骨折的初步经验

目的 比较骨科机器人辅助经皮椎弓根螺钉内固定术治疗胸腰段骨折与传统后路椎弓根螺钉内固定术、C形臂X线机透视导航经皮椎弓根螺钉内固定术的临床疗效,探讨机器人辅助手术治疗胸腰段骨折的微创化与精准化价值。方法 2018年2月—2019年6月,收治无神经症状胸腰段骨折患者52例,18例接受机器人辅助经皮椎弓根螺钉内固定术治疗（机器人组）,15例接受C形臂X线机透视导航经皮椎弓根螺钉内固定术治疗（透视组）,19例接受传统后路椎弓根螺钉内固定术治疗（传统组）。记录并比较3组的手术时间、透视时间、辐射剂量、术中出血量、置钉准确率、卧床时间、住院天数,术前、术后6个月伤椎前缘相对高度及Cobb角,以及术前、术后3 d、术后6个月的疼痛视觉模拟量表（VAS）评分和日本骨科学会（JOA）评分。结果 所有手术顺利完成,未出现手术相关并发症。所有患者随访6~12个月,平均8个月。机器人组和透视组的手术时间、术中出血量、卧床时间、住院天数均少于传统组,差异有统计学意义（P<0.05）;透视组透视时间最长、辐射剂量最大,机器人组透视时间最短、辐射剂量最少,差异有统计学意义（P<0.05）;机器人组置钉准确率高于透视组和传统组,差异有统计学意义（P<0.05）。3组患者术后6个月伤椎前缘相对高度、Cobb角、VAS评分和JOA评分均较术前改善,差异有统计学意义（P<0.05）。3组术前、术后3 d和术后6个月伤椎前缘相对高度、Cobb角及JOA评分差异无统计学意义（P>0.05）;机器人组与透视组术后3 d VAS评分优于传统组且差异有统计学意义（P<0.05）,术前及术后6个月3组VAS评分差异无统计学意义（P>0.05）。结论 机器人辅助经皮内固定术是治疗无神经症状胸腰段骨折的有效方法,具有手术时间短、精度高、创伤小、辐射少、患者术后恢复快等优势,满足适应证时可作为优先选择。     

机器人辅助经椎间孔入路脊柱内窥镜手术治疗单节段腰椎椎间盘突出症

目的 探讨“天玑”骨科机器人辅助经椎间孔入路脊柱内窥镜手术治疗单节段腰椎椎间盘突出症（LDH）的临床效果。方法 2018年6月—2020年6月,北京积水潭医院收治单节段LDH患者33例,其中16例采用传统经椎间孔入路脊柱内窥镜手术治疗（A组）,17例采用“天玑”骨科机器人辅助经椎间孔入路脊柱内窥镜手术治疗（B组）。记录术中医师及患者辐射暴露次数;麻醉后体位摆放完成至置入工作通道总时间（T0）;穿刺针刺破皮肤至导针初次放置到满意位置的时间（T1）;导针放置完成到置入工作通道时间（T2）;其他时间（T3）,A组包括穿刺前透视定位穿刺点等时间,B组包括示踪器放置、术中X线扫描、穿刺通道制订等时间。记录术前和术后3 d、1个月、6个月时腿痛视觉模拟量表（VAS）评分、Oswestry功能障碍指数（ODI）和日本骨科学会（JOA）评分。结果 所有手术顺利完成,无并发症发生。B组医师辐射暴露次数明显少于A组,患者辐射暴露次数明显多于A组,差异均有统计学意义（P < 0.05）。2组T0差异无统计学意义（P > 0.05）;B组T1、T2比A组短,T3比A组长,差异均有统计学意义（P < 0.05）。2组术后各时间点腿痛VAS评分、ODI和JOA评分明显优于术前,差异均有统计学意义（P < 0.05）,术后各时间点组间差异无统计学意义（P > 0.05）。结论 “天玑”骨科机器人辅助经椎间孔入路脊柱内窥镜手术治疗单节段LDH临床效果良好,且术中医师辐射暴露次数少,穿刺操作准确、便捷,稳定性可靠。     

电磁导航辅助经椎间孔脊柱内窥镜系统治疗腰椎椎间盘突出症

目的 探讨电磁导航辅助经椎间孔脊柱内窥镜系统（TESSYS）靶向定位穿刺治疗腰椎椎间盘突出症（LDH）的临床价值。方法 回顾性分析2018年4月—2019年4月在洛阳正骨医院接受TESSYS治疗的72例LDH患者临床资料,其中36例术中采用电磁导航靶向定位穿刺（导航组）,另36例采用常规定位穿刺（常规组）。记录手术时间、透视次数、透视时间、穿刺时间、减压时间及相关并发症发生情况。采用疼痛视觉模拟量表（VAS）评分、日本骨科学会（JOA）评分、Oswestry功能障碍指数（ODI）及改良MacNab标准评价临床疗效。结果 所有手术顺利完成,患者随访7~18个月,平均12.1个月;导航组导航建立时间为（11.97±2.14）min。导航组手术时间、透视次数、透视时间、穿刺时间均少于常规组,差异有统计学意义（P<0.05）;2组减压时间差异无统计学意义（P>0.05）。2组末次随访腿痛VAS评分、JOA评分、ODI较术前明显改善,差异均有统计学意义（P<0.05）;组间比较差异无统计学意义（P>0.05）。改良MacNab标准评价疗效：导航组优21例,良12例,可3例,优良率为91.7%（33/36）;常规组优18例,良13例,可5例,优良率为86.1%（31/36）;组间差异无统计学意义（P>0.05）。所有患者均未发生严重神经根损伤、血管损伤和感染等并发症,常规组4例患者在穿刺过程中出现一过性神经根疼痛,调整穿刺方向后疼痛消失。结论 电磁导航辅助TESSYS靶向定位穿刺治疗LDH能减少手术时间、术中透视次数、穿刺时间,与常规穿刺方法疗效及安全性相当,可降低TESSYS学习曲线,提高青年医师一次性穿刺成功率。     

经椎间孔入路经皮内窥镜下椎间盘切除术中采用可视化椎间孔成形技术治疗单节段腰椎椎管狭窄症

目的 探讨经椎间孔入路经皮内窥镜下椎间盘切除术（PETD）中采用可视化椎间孔成形技术治疗单节段腰椎椎管狭窄症（LSS）的疗效和安全性。方法 回顾分析2018年3月—2019年3月采用PETD治疗的58例单节段LSS患者临床资料,其中36例采用“V”区解剖引导的可视化椎间孔成形技术（观察组）,22例采用传统椎间孔成形技术（对照组）。记录2组手术时间、术中透视次数、术中出血量、住院时间及并发症（神经根损伤、硬膜囊损伤、血管损伤等）发生情况。术前及术后1、12个月时采用疼痛视觉模拟量表（VAS）评分和Oswestry功能障碍指数（ODI）评估腰腿痛程度及腰椎功能。采用改良MacNab标准评估疗效。结果 所有手术顺利完成,患者随访（13.54±0.56）个月。观察组手术时间、术中透视次数显著低于对照组,差异有统计学意义（P < 0.05）;2组术中出血量和住院时间差异无统计学意义（P > 0.05）。2组患者术后各时间点VAS评分、ODI均较术前显著改善,差异有统计学意义（P < 0.05）,且VAS评分、ODI均随术后随访时间增加进一步改善;观察组术后1个月VAS评分、ODI显著低于对照组,差异有统计学意义（P < 0.05）,2组术后12个月VAS评分、ODI相比,差异无统计学意义（P > 0.05）。2组疗效优良率差异无统计学意义（P > 0.05）。2组术后均未发生严重并发症。结论 PETD中采用可视化椎间孔成形技术治疗单节段LSS与传统椎间孔成形技术疗效相当,并可减少穿刺次数和成形扩张操作次数,减轻患者机体创伤,缩短恢复时间,并可降低医患辐射量,值得临床推广。     

超声容积导航与X线透视引导下椎间孔镜技术治疗腰椎间盘突出症的临床对比

目的探讨超声容积导航与X线透视引导下椎间孔镜技术治疗腰椎间盘突出症(lumbar disc herniation,LDH)的临床疗效。方法纳入2016年1月~2017年6月治疗的76例LDH患者,均采用经皮椎间孔镜下椎间盘切除术(percutaneous transforaminal endoscopic discectomy,PTED)治疗,依据其术中穿刺引导技术的不同将其分为两组,对照组采用X线透视引导穿刺,观察组采用超声容积导航引导穿刺。记录两组患者手术相关指标,随访12个月以上,比较两组患者疗效及并发症发生情况。结果观察组手术时间、穿刺时间、术中透视次数显著低于对照组,一次穿刺成功率显著高于对照组,差异有统计学意义(P0.05);两组术后ODI评分、VAS评分均显著降低(P0.05),但组间差异均无统计学意义(P0.05);两组患者均无严重并发症发生,复发率差异无统计学意义(P0.05)。结论超声容积导航能获得与C型臂X线机透视引导下PTED治疗LDH一致的近期疗效,但超声容积导航能降低穿刺时间、提高穿刺成功率,减少放射损伤。     

术中滑轨CT辅助在经皮骶髂关节螺钉治疗骨盆后环损伤中的应用

目的：比较术中滑轨CT联合C形臂X线机辅助与单纯使用C形臂X线机辅助透视下经皮骶髂关节螺钉治疗骨盆后环损伤临床疗效。方法：自2018年12月至2022年2月收治76例骨盆后环损伤患者,其中,C形臂联合滑轨CT辅助下行内固定治疗39例为CT组,男23例,女16例,年龄(44.98±7.33)岁;仅在C形臂透视下行内固定治疗37例为C形臂组,男24例,女13例,年龄(44.37±10.82)岁。合并有前环骨折患者42例,均采用经皮髂前下棘内置外固定架(internal fixation,INFIX)或耻骨上支螺钉固定骨盆前环。术后比较两组随访时间、置钉时间、并发症。比较两组Matta复位评价、Majeed疗效评价、CT分级及二次手术翻修率。结果：CT组置钉时间(32.63±7.33) min,短于C形臂组(52.95±10.64) min(t=-9.739,P＜0.05)。CT组随访时间(11.97±1.86)个月,C形臂组(12.03±1.71)个月,两组比较差异无统计学意义(P＞0.05)。两组术后并发症发生比较,差异无统计学意义(χ²=0.159,P＞0.05)。CT组Matta复位评价结果(Z=2.79,P＜0.05)、Majeed疗效评价结果(Z=2.79,P＜0.05)、CT分级(Z=2.83,P＜0.05)均优于C形臂组。CT组二次手术翻修率低于C形臂组(χ²=5.641,P＜0.05)。结论：术中滑轨CT联合C形臂辅助下经皮骶髂关节螺钉置入手术与传统C形臂透视相比,具有手术时间短、准确度及安全性高、术后二次翻修率显著下降等特点,是重建骨盆骨折后环稳定性的有效方法之一。     

自制辅助穿刺装置联合三维可视化技术在内窥镜下经椎间孔腰椎间盘切除术中的应用

目的 探讨自制辅助穿刺装置联合三维可视化技术在经皮内窥镜下经椎间孔腰椎间盘切除术（PETD）治疗腰椎间盘突出症（LDH）中的应用效果。方法 2021年1月至2022年5月，安徽医科大学附属亳州医院脊柱外科94例LDH病人接受PETD治疗，采用随机数字表法选择通道建立方法。46例采用自制辅助穿刺装置联合三维可视化技术建立通道（研究组），48例采用传统穿刺法建立通道（对照组），两组通道建立后采用经皮椎间孔镜（TESSYS）技术完成椎间盘切除和神经根减压。分析两组透视次数、穿刺次数、穿刺时间、一次穿刺成功数、住院天数、手术时间及末次随访时改良MacNab标准评价结果。结果 所有病人都顺利完成手术和随访，无严重并发症发生。研究组和对照组的随访时间分别为（8.9±2.1）个月、（8.7±1.8）个月，两组差异无统计学意义（t=0.622，P=0.109）。研究组的穿刺时间少于对照组［（14.1±4.3） min vs. （19.1±3.7） min］，穿刺次数少于对照组［（3.8±2.1）次 vs. （7.9±2.6）次］，透视次数少于对照组［（8.3±3.3）次 vs. （15.1±4.2）次］，手术时间少于对照组［（79.0±8.5） min vs. （89.7±13.4） min］，一次穿刺成功数多于对照组（12例 vs. 4例），组间比较，差异均有统计学意义（P＜0.05）。两组住院天数以及末次随访时的优良率比较，差异无统计学意义（P＞0.05）。结论 采用自制辅助穿刺装置联合三维可视化技术建立通道可以明显减少穿刺次数、透视次数、穿刺时间和手术时间，一次穿刺成功率较高，手术安全且疗效满意，这种新的通道建立方法是可行的。     

硬膜外运动-感觉分离麻醉在经椎间孔入路经皮内窥镜下椎间盘切除术中的应用

目的 探讨硬膜外运动-感觉分离麻醉在经椎间孔入路经皮内窥镜下椎间盘切除术中（PETD）的应用效果。方法 2017年10月—2020年1月，采用PETD治疗腰椎椎间盘突出症（LDH）患者137例，其中77例术中采用硬膜外运动-感觉分离麻醉（分离组），60例采用局部麻醉（局部组）。记录2组患者手术时间、透视次数及并发症发生情况。术前、术后3个月采用疼痛视觉模拟量表（VAS）评分评估疼痛程度，并分别记录切开皮肤时、椎间孔成形时及处理后纵韧带时的VAS评分；采用日本骨科学会（JOA）评分评估腰椎功能。术后3个月随访时统计患者再手术意愿。结果 所有手术顺利完成。分离组随访12 ~ 25（17.33±6.12）个月，局部组随访12 ~ 27（18.56±6.11）个月。分离组手术时间短于局部组，再手术意愿优于局部组，差异均有统计学意义（P < 0.05）；2组透视次数差异无统计学意义（P > 0.05）。2组术后3个月VAS评分、JOA评分较术前明显改善，差异均有统计学意义（P < 0.05）；组间差异无统计学意义（P > 0.05）。分离组在椎间孔成形时、处理后纵韧带时的VAS评分优于局部组，差异均有统计学意义（P < 0.05）；2组切开皮肤时的VAS评分差异无统计学意义（P > 0.05）。2组并发症发生率差异无统计学意义（P > 0.05）。结论 硬膜外运动-感觉分离麻醉用于PETD具有患者接受程度高、麻醉效果好等优点，可以有效降低术中疼痛，利于手术顺利完成。     

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.     

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.     

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.