CT导航系统在重度僵硬性脊柱畸形矫形术中的置钉准确性及临床疗效评估

目的 评估CT导航系统在重度僵硬性脊柱畸形矫形术中的置钉准确性及临床疗效。方法 回顾性纳入2017年1月至2022年12月我院收治的43例重度僵硬性脊柱畸形病人,其中21例采用术中CT导航系统辅助置钉（421枚螺钉）的病人纳入导航组,22例采用传统徒手置钉（386枚螺钉）的病人纳入徒手组。收集两组病人的一般资料、手术前后主弯Cobb角、矫正率、置钉数量以及顶椎区域置钉数量。采用Gertzbein和Robbins分级分析两组病人术后CT图像,以评估置钉准确性。结果 两组病人手术前后主弯Cobb角及矫正率比较,差异无统计学意义（P＞0.05）。较之徒手组,导航组置入于顶椎区域的螺钉数量更多［（7.37±1.12）个 vs. （6.45±0.96）个］,手术时间更长［（376.19±56.26） min vs. （331.36±50.92） min］,差异均有统计学意义（P＜0.05）;但出血量无明显差异（P＞0.05）。两组病人总体置钉准确率比较,差异无统计学意义（P=0.586）;但在顶椎区域,导航组置钉准确率显著高于徒手组（96.1% vs. 89.4%,χ²=5.051,P=0.025）。此外,术中CT导航系统明显降低了椎弓根内侧穿孔率（χ²=5.122,P=0.024）。结论 CT导航系统可有效提高重度僵硬性脊柱畸形顶椎区域的置钉准确性。     

术前磁共振评估距骨软骨损伤范围的准确性研究

目的 探讨术前MRI评估距骨软骨损伤病灶范围的准确性。方法 纳入我院2020年1月至2021年6月的40例术前行MRI检查并接受手术治疗的距骨软骨损伤病人,通过测量术前MRI和术中损伤病灶的冠状面最长径和矢状面最长径,计算其面积,并比较术前MRI和术中测量数据的差异。结果 术前MRI测量的距骨软骨损伤病灶矢状面最长径、冠状面最长径、面积均大于术中测量数据［（13.3±3.8） mm vs. （9.4±3.9） mm,（9.0±2.5） mm vs.（5.2±2.1） mm,（96.5±45.8） mm² vs. （41.8±29.3） mm²,P＜0.05］。术前MRI评估与术中评估一致率为60%（24/40）,术前MRI过度评估率为35%（14/40）,术前MRI评估不足率为5%（2/40）。结论 与术中测量相比,MRI用于术前评估距骨软骨损伤病灶准确性较低,容易出现过度评估。     

机器人导航下股骨颈动力交叉钉系统治疗股骨颈骨折的疗效分析

目的 探讨机器人导航下股骨颈动力交叉钉系统（femoral neck system,FNS）治疗股骨颈骨折的临床疗效。方法 回顾性分析2019年11月至2021年8月我院采用FNS治疗股骨颈骨折的57例病人的临床资料,其中27例行机器人导航下FNS治疗（机器人组）,30例采用常规人工FNS治疗（人工组）,比较两组病人的手术时间、术中出血量、术中透视次数、术后髋关节Harris评分、骨折愈合时间及术后并发症发生率等指标。结果 机器人组的手术时间为（81.0±9.2） min,少于人工组（86.7±12.0） min,但差异无统计学意义（P＞0.05）。机器人组的术中出血量和透视次数分别为（25.5±7.5） mL、（16.4±2.8）次,均少于人工组的（37.3±11.3） mL、（20.1±3.0）次,差异有统计学意义（P＜0.05）。机器人组一次性置钉成功率为100%,人工组为56.7%,差异有统计学意义（χ²=15.157,P＜0.001）。两组术后并发症发生率、骨折愈合时间及术后髋关节Harris评分比较,差异无统计学意义（P＞0.05）。结论 机器人导航下FNS手术治疗股骨颈骨折是一种精准、微创、安全有效的方法。     

单侧双通道内镜单纯髓核摘除术对椎旁肌肉的影响

目的 研究单侧双通道内镜单纯髓核摘除术（unilateral biportal endoscopic discectomy，UBED）对于椎旁肌肉的影响，并评估椎旁肌肉改变与随访时间的相关性。方法 回顾性分析2020年3月至2021年12月就诊于我院脊柱外科并接受UBED手术治疗的42例病人的临床资料。所有病人在术前、术后、末次随访时均行MRI检查。收集病人基本信息、末次随访时间、MRI图像、腰部和腿部的疼痛视觉模拟量表（visual analogue scale，VAS）评分及Oswestry功能障碍指数（Oswestry disability index，ODI）。结果 与术前相比，手术侧多裂肌术后信号强度、水肿面积均明显上升［41.02±14.40 vs. 19.14±10.11，（26.95±14.70） cm² vs. （10.17±5.41） cm²］；与非手术侧相比，术后手术侧多裂肌信号强度、横截面积、水肿面积占比明显升高［41.02±14.40 vs. 21.92±11.07，（39.27±12.82）cm² vs. （33.66±11.79）cm²，26.95%±14.70% vs. 11.53%±7.06%］；上述指标比较，差异有统计学意义（P＜0.05）。手术对于竖脊肌上述指标的改变未见统计学意义（P＞0.05）。手术侧多裂肌信号强度、水肿面积占比均与随访时间存在显著负相关（r=-0.53、r=-0.47）。结论 UBED对于椎旁肌肉的影响集中于手术侧多裂肌，但其损伤是可逆的。     

机器人辅助人工全髋关节置换的短期疗效分析

目的　探讨机器人辅助人工全髋关节置换术（total hip arthroplasty, THA）的短期疗效。方法　回顾性分析2018年8月至2019年3月于我科采用MAKO机器人系统辅助植入臼杯行THA手术治疗的79例（100髋）病人的临床资料,纳入机器人辅助组,并选择同一手术医师施行的80例（100髋）徒手THA病人纳入对照组,均采用标准髋关节后外侧入路。收集比较两组病人的围手术期相关信息,如手术时间、住院时间、髋臼杯位置、术后下肢长度差异（limb length discrepancy, LLD）、围手术期并发症及髋关节Harris评分（hip Harris score, HHS）。结果　病人术后均得到3个月以上随访,两组均未发生髋关节脱位、无菌性松动、假体周围感染或翻修。机器人辅助组的手术时间为（95.92±15.64） min,明显长于对照组的（83.12±18.22） min,两组比较,差异有统计学意义（t=3.309,P=0.001）。两组的术后HHS均较术前显著改善,但组间比较,差异无统计学意义（P＞0.05）。机器人辅助组的前倾角、外展角、LLD和偏心距差异分别为19.05°±5.03°、41.14°±3.66°、（2.87±3.75） mm、（3.34±1.79） mm,对照组分别为16.91°±5.48°、40.35°±6.57°、（4.23±3.12） mm、（3.98±2.04） mm;两组的前倾角和LLD比较,差异均有统计学意义（P均＜0.05）,但两组间的外展角和偏心距差异比较,差异无统计学意义（P＞0.05）。机器人辅助组的手术假体位于Lewinnek安全区内的比例更高（91% vs. 82%）,但两组间比较,差异无统计学意义（χ²=3.468,P=0.063）。结论　机器人辅助THA能够优化髋臼杯假体植入的精确性,不增加手术的并发症,但其远期效果仍需进一步研究证实。     

腹腔镜下NOSES手术与小切口手术治疗结直肠癌的临床疗效比较

背景与目的 腹腔镜下经自然腔道取标本手术（NOSES）利用人体的天然腔道如取出手术标本,无需在腹壁进行小切口,有微创优势。本研究探讨腹腔镜下结直肠癌NOSES与腹腔镜小切口手术治疗效果。方法 选取2018年4月—2020年4月收治的结直肠癌患者89例,分为观察组（n=42）和对照组（n=47）,观察组给予腹腔镜下NOSES治疗,对照组给予腹腔镜小切口手术治疗,观察分析两组手术治疗效果差异。结果 观察组手术时间明显长于对照组［（241.18±68.87）min vs. （180.05±61.12） min,P<0.05］;观察组首次排气时间、首次排便时间和首次下地时间明显优于对照组［（2.50±0.80）d vs. （3.45±0.71）d,（3.20±0.95）d vs. （4.22±0.81）d,（1.25±0.32）d vs. （1.80±0.75）,P<0.05］;观察组术后24 h疼痛VAS评分、额外使用止痛药比例明显少于对照组［（2.01±0.87）分vs. （3.95±0.80）分,7.14% vs. 23.40%,P<0.05］;观察组术后1周胃泌素（GAS）和胃动素（MTL）明显高于对照组［（66.15±7.21）mmol/L vs.（60.10±6.80）mol/L,（230.05±31.17）pg/mL vs. （197.76±30.81）pg/mL,P<0.05］。结论 腹腔镜下NOSES治疗结直肠癌有较好的效果,具有术后疼痛轻、胃肠功能影响小等优点。     

直接前方入路与后外侧入路初次全髋关节置换术治疗股骨头坏死的早期临床疗效比较

目的 比较直接前方入路（direct anterior approach, DAA）和后外侧入路（posterolateral approach, PA）行全髋关节置换术（total hip arthroplasty, THA）治疗股骨头坏死（osteonecrosis of the femoral head, ONFH）的早期临床疗效。方法 回顾性分析我院2018年5月至2019年5月行THA的72例OFNH病人的临床资料,根据手术入路的不同分为PA组和DAA组,每组36例。统计病人年龄、性别、身体质量指数（body mass index, BMI）、病因及国际骨循环学会（Association Research Circulation Osseous, ARCO）分期等资料,观察比较两组病人手术切口长度、手术时间、术中出血量、术后引流量、术后下地活动时间、术后住院天数和出院时髋关节活动度等围手术期资料以及术前、术后（5 d,1、6个月）不同时间点的疼痛视觉模拟量表（visual analogue scale, VAS）,采用Harris髋关节评分评价病人关节功能恢复情况。结果 所有病人均获得随访,平均随访时间为6个月。DAA组的手术时间和出院时髋关节活动度明显长于PA组［（109.44±11.00） min vs. （79.81±10.16） min,166.94°±15.32° vs. 123.61°±17.47°］,但其切口长度、术中出血量、术后引流量、术后下地行走时间、术后住院天数均小于PA组［（9.25±1.50）cm vs. （13.14±2.08） cm,（213.61±47.22） ml vs. （287.03±55.24） ml,（77.33±29.35） ml vs. （115.89±36.33） ml,（1.11±0.32） d vs. （1.50±0.61） d,（6.42±1.23） d vs. （8.25±1.42） d］,差异均有统计学意义（P均＜0.05）。DAA组术后5 d及1个月的VAS评分及Harris髋关节评分均明显优于PA组,差异均有统计学意义（P均＜0.05）,而术后6个月时两组的VAS评分及Harris髋关节评分的差异无统计学意义（P＞0.05）。结论 同PA相比,采用DAA行THA,病人术中创伤小、出血少,术后早期关节功能恢复更快、疼痛感更轻,能显著缩短病人的住院时间,从而获得较高的病人满意度。     

全内镜大通道下单侧入路双侧减压治疗腰椎管狭窄症的短期疗效

目的 探讨脊柱全内镜大通道下单侧入路双侧减压（Endo-ULBD）治疗单节段腰椎管狭窄症（LSS）的短期临床疗效。方法 前瞻性分析我院2020年6月至2022年6月采用Endo-ULBD治疗的33例单节段LSS的病人。术前术后采用疼痛视觉模拟量表（VAS）、Oswestry功能障碍指数（ODI）、改良MacNab标准评价临床疗效。结果 所有病人手术顺利，1例病人术后失访，最终32例病人获得随访，随访时间为（16.52±4.28）个月。腰痛VAS评分由术前的（6.28±1.71）分降为术后12个月的（1.59±1.29）分，腿痛VAS评分由术前的（5.88±2.59）分降为术后12个月的（1.66±1.26）分，ODI由术前的67.47%±10.28%降至17.50%±15.72%，手术前后差异均有统计学意义（P＜0.05）。术前与末次随访时椎间高度指数、腰椎前凸角比较，差异无统计学意义（P＞0.05）。末次随访MacNab优良率为93.75%（30/32）。术中出现1例硬膜囊撕裂，1例硬膜外血肿，对症处理后症状缓解。结论 Endo-ULBD治疗单节段LSS的短期临床效果良好，但长期疗效需进一步随访。     

骨科手术机器人精准导航辅助空心螺钉内固定治疗中青年股骨颈骨折的疗效分析

目的 探讨应用骨科手术机器人精准导航辅助空心螺钉内固定治疗中青年股骨颈骨折的疗效及优势。方法 回顾性分析武汉科技大学附属普仁医院2021年1月至2022年6月采用多枚空心螺钉内固定法治疗的30例中青年股骨颈骨折病人。根据术中是否使用机器人辅助置钉分为两组，观察组采用天玑骨科手术机器人辅助置钉，男7例，女8例，年龄为（48.67±7.83）岁；对照组采用传统方法在“C”型臂X线机监视下置钉，男6例，女9例，年龄为（48.60±7.71）岁。记录并比较两组病人的手术时间、术中透视次数、术中失血量、住院时间、骨折愈合时间、术后并发症发生情况和术后6个月Harris评分。结果 本研究共置入90枚空心螺钉，每例病人置入3枚空心螺钉。病人均获得随访，随访时间为6~12个月，平均8.7个月。观察组病人手术时间、术中透视次数、术中失血量、住院时间均显著优于对照组［（56.93±5.65） min vs. （69.87±3.96） min，（12.73±1.28）次 vs. （18.87±2.47）次，（12.60±1.80） mL vs. （25.53±2.39） mL，（8.67±1.18） d vs. （10.87±1.19） d］，差异有统计学意义（P＜0.05）。随访期间两组病人髋部疼痛明显缓解，骨折均愈合良好，无明显并发症发生，观察组病人骨折愈合时间优于对照组，但差异无统计学意义（P＞0.05）。术后6个月观察组髋关节Harris评分显著高于对照组，差异有统计学意义（P＜0.05）。结论 与传统“C”型臂X线机监视下置钉相比，骨科手术机器人辅助空心螺钉内固定治疗中青年股骨颈骨折，可以显著缩短病人的手术时间和住院时间，减少病人术中透视次数和术中失血量，更有利于病人髋关节功能的恢复，临床效果满意。     

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。     

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 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.     

Synergistic interaction between the effects of propofol and midazolam with fentanyl on phrenic nerve activity in rabbits

Background: It has been shown that the depressive effects of both propofol and midazolam on consciousness are synergistic with opioids, but the nature of their interactions on other physiological systems, e. g. respiration, has not been fully investigated. The present study examined the effect of propofol and midazolam alone and in combination with fentanyl on phrenic nerve activity (PNA) and whether such interactions are additive or synergistic. Methods: PNA was recorded in 27 anaesthetised and artificially ventilated rabbits. In three groups, propofol, fentanyl and midazolam were administered intravenously in incremental doses to construct dose-response curves for the depressant effects of each one on PNA. In another two groups, the effect of pretreatment with either fentanyl 1 μg · kg^?1 i. v. or midazolam 0.05 mg · kg^?1 i. v. on the effects of propofol and fentanyl respectively on PNA were studied. Results: Propofol and fentanyl caused a dose-dependent depression of PNA with complete abolition at the highest total doses of 16 mg · kg^?1 i. v. and 32 μg · kg^?1 i. v., respectively. In contrast, midazolam in incremental doses to a total of 0.8 mg · kg^?1 reduced mean PNA by 63%, but approximately 12% of PNA remained at a total dose as high as 6.4 mg · kg^?1. The mean ED₅₀s, calculated from dose-response curves, were 5.4 mg · kg^?1, 3.9 μg · kg^?1 and 0.4 mg · kg^?1 for propofol, fentanyl and midazolam, respectively. Initial doses of either fentanyl 1 μg · kg^?1 i. v. or midazolam 0.05 mg · kg^?1 i. v. acted synergistically with subsequent doses of either propofol or fentanyl to abolish PNA at total doses of 8 mg · kg^?1 and 8 μg · kg^?1, respectively. Conclusion: Fentanyl has a synergistic interaction with both propofol and midazolam on PNA and hence potentially on respiration.     

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.