一期前后联合入路全脊椎切除在颈椎孤立性浆细胞瘤中的应用北大核心CSCD

目的探讨一期经前后联合入路全脊椎切除加重建术治疗颈椎孤立性浆细胞瘤(solitary plasmacytoma,SP)的可行性,以期为临床治疗颈椎SP提供可靠、有效的手术方式。方法回顾分析2000年6月—2015年3月行一期经前后联合入路全脊椎切除的12例颈椎SP患者临床资料。其中男8例,女4例;年龄28~74岁,平均46岁。病程3~15个月,平均8.4个月。发病部位:C_2 2例,C_3 4例,C_4 2例,C_5、C_6 1例且为复发病例,C_73例。根据WBB(Weinstein-Boriani-Biagini)分期,累及椎体且超过一侧4扇区或9扇区8例,同时超过两侧4扇区或9扇区4例;肿瘤侵及A^D层7例,B^D层5例。术前脊髓损伤按Frankel分级,B级1例,C级6例,D级5例。5例椎动脉被侵袭,其中4例单侧累及,1例双侧累及;病变累及单椎节11例,2个椎节骨质破坏1例。患者术后均接受辅助放疗。记录手术时间、术中出血量;采用Frankel分级评价神经功能恢复情况,疼痛视觉模拟评分(VAS)评估疼痛恢复情况。结果手术时间6.8~9.3 h,平均7.2 h;术中出血量1 100~2 600 mL,平均1 600 mL。1例C_5、C_6复发SP患者术后1周出现食道瘘,1例术后出现伤口脂肪液化,均经相应处理后治愈;其余患者均未出现脊髓神经功能损伤加重,无大血管损伤(特别是椎动脉),膈神经、喉上、喉返神经损伤,呼吸衰竭等并发症。12例患者均获随访,随访时间27~98个月,平均58个月。末次随访时神经功能均恢复至Frankel E级;VAS评分由术前(6.7±2.7)分减小至(1.1±0.7)分,差异有统计学意义(t=2.485,P=0.014)。2例患者分别于术后29、37个月复发,均行辅助化疗,其中1例进展为多发性骨髓瘤,术后43个月死于多器官功能衰竭;另1例患者带瘤生存。1例术后4年出现内固定物松动、断裂,予以翻修。其余患者随访期间均未见肿瘤复发或恶变,无内固定物松动、断裂等并发症发生。结论手术切除是治疗颈椎SP的主要手段,一期经前后联合入路全脊椎切除术能明显降低颈椎SP复发率,并能缓解脊髓压迫症状,最大限度改善患者生存质量。进展到多发性骨髓瘤的患者应接受个体化治疗,但预后较差。     

一期前后联合入路全脊椎切除在颈椎孤立性浆细胞瘤中的应用

目的探讨一期经前后联合入路全脊椎切除加重建术治疗颈椎孤立性浆细胞瘤(solitary plasmacytoma,SP)的可行性,以期为临床治疗颈椎SP提供可靠、有效的手术方式。方法回顾分析2000年6月—2015年3月行一期经前后联合入路全脊椎切除的12例颈椎SP患者临床资料。其中男8例,女4例;年龄28~74岁,平均46岁。病程3~15个月,平均8.4个月。发病部位:C_2 2例,C_3 4例,C_4 2例,C_5、C_6 1例且为复发病例,C_73例。根据WBB(Weinstein-Boriani-Biagini)分期,累及椎体且超过一侧4扇区或9扇区8例,同时超过两侧4扇区或9扇区4例;肿瘤侵及A~D层7例,B~D层5例。术前脊髓损伤按Frankel分级,B级1例,C级6例,D级5例。5例椎动脉被侵袭,其中4例单侧累及,1例双侧累及;病变累及单椎节11例,2个椎节骨质破坏1例。患者术后均接受辅助放疗。记录手术时间、术中出血量;采用Frankel分级评价神经功能恢复情况,疼痛视觉模拟评分(VAS)评估疼痛恢复情况。结果手术时间6.8~9.3 h,平均7.2 h;术中出血量1 100~2 600 mL,平均1 600 mL。1例C_5、C_6复发SP患者术后1周出现食道瘘,1例术后出现伤口脂肪液化,均经相应处理后治愈;其余患者均未出现脊髓神经功能损伤加重,无大血管损伤(特别是椎动脉),膈神经、喉上、喉返神经损伤,呼吸衰竭等并发症。12例患者均获随访,随访时间27~98个月,平均58个月。末次随访时神经功能均恢复至Frankel E级;VAS评分由术前(6.7±2.7)分减小至(1.1±0.7)分,差异有统计学意义(t=2.485,P=0.014)。2例患者分别于术后29、37个月复发,均行辅助化疗,其中1例进展为多发性骨髓瘤,术后43个月死于多器官功能衰竭;另1例患者带瘤生存。1例术后4年出现内固定物松动、断裂,予以翻修。其余患者随访期间均未见肿瘤复发或恶变,无内固定物松动、断裂等并发症发生。结论手术切除是治疗颈椎SP的主要手段,一期经前后联合入路全脊椎切除术能明显降低颈椎SP复发率,并能缓解脊髓压迫症状,最大限度改善患者生存质量。进展到多发性骨髓瘤的患者应接受个体化治疗,但预后较差。     

后路一期整块全脊椎切除治疗胸腰椎肿瘤

目的:总结后路一期整块全脊椎切除的手术经验、并发症和对神经功能的影响。方法:2006年8月至2007年9月对9例脊柱肿瘤患者进行后路一期整块全脊椎切除术,病理诊断包括4例骨巨细胞瘤,1例尤文肉瘤,1例孤立性浆细胞瘤,3例孤立性骨转移癌。8例患者肿瘤位于胸椎,1例位于腰椎。4例患者术前接受了病椎的选择性节段动脉栓塞。所有病例术前均根据Tomita脊柱肿瘤外科分期进行评估,2例患者为间室内,7例为间室外。对切除的肿瘤标本进行外科边界检查。采用Frankel分级对神经功能进行评价。结果:平均术中失血量5800ml,平均手术时间291min。2例患者获得广泛边界,其他为边缘性边界。1例术后血肿形成,1例脑脊液漏致胸腔积液,1例血肿形成合并脑脊液漏。随访14～36个月,平均25.8个月,在随访期内肿瘤无复发,2例转移癌及1例尤文肉瘤患者带瘤生存,1例转移癌死亡,4例无瘤生存。术后所有病例神经功能均获得改善或保持原有水平。结论:对具有适应证的胸腰椎肿瘤患者进行后路一期整块全脊椎切除手术可以获得满意的局部控制和功能恢复,但仍需要进一步随访并提高技术,减少合并症的发生。     

全脊椎切除及脊柱稳定性重建治疗颈胸段脊柱肿瘤的疗效分析

目的 :探讨颈胸段脊柱肿瘤全脊椎切除的手术方式、脊柱重建策略及治疗效果。方法 :回顾性分析我院自2008年1月~2013年12月行全脊椎切除术治疗的颈胸段脊柱肿瘤病例11例,病理诊断包括骨巨细胞瘤5例,骨母细胞瘤1例,Ewing肉瘤1例,浆细胞性骨髓瘤1例,甲状腺滤泡型转移癌2例,前列腺转移癌1例。患者均有不同程度的胸背部疼痛,术前VAS评分为7.45±0.82分;脊髓损伤神经功能Frankel分级B级1例,C级3例,D级6例,E级1例。所有病例术前根据Tomita脊柱肿瘤外科分期评估均为间室外病变。4例C7~T1段肿瘤行一期前后联合入路全脊椎切除,前方钛网、钛板重建;7例T2~T4段肿瘤行单一后路整块全脊椎切除(TES),前方单纯钛网重建。两种术式后方均为钉棒系统重建。观察患者术中术后并发症以及脊柱重建稳定性情况。结果:手术时间298~573min,平均423.9min;术中失血量800~3800ml,平均2077ml。4例术中胸膜破裂,2例术后神经功能一过性下降,7例术中结扎病椎神经根,残留轻度胸前区不适。所有患者均获随访,平均随访34.7个月,1例前列腺转移癌患者死亡,其余均无局部复发。术后患者疼痛明显改善,VAS评分由术前7.45±0.82分下降至术后2.55±0.69分(P<0.05)。术后神经功能2例(术前D级1例,E级1例)保持原有水平,余均获得改善,均未出现内固定失败。结论:全脊椎切除治疗颈胸段脊柱肿瘤可以获得满意的局部控制,缓解疼痛,改善神经功能,应根据肿瘤位于颈胸段脊柱近端(C7~T1)或远端(T2~T4)而制定个体化手术方式及脊柱重建策略。     

经后路全脊椎整块切除术治疗胸腰椎肿瘤

目的:探讨经后路全脊椎整块切除术(TES)治疗胸腰椎肿瘤的方法及其疗效.方法:2005年1月～2007年7月收治胸腰椎肿瘤患者6例,其中男3例,女3例,年龄20～77岁;Tomita分型,Ⅲ型1例,Ⅳ型3例,Ⅴ型2例;T3 1例,,T8 2例,T9 1例.T11 1例,L1 1例;骨巨细胞瘤1例,椎体单发骨髓瘤1例,转移性腺癌4例;术前脊髓功能Frankel分级B级2例,D级1例,E级3例.均应用改良弧形骨刀行一期后入路全脊椎整块切除术,同时采用钛网植骨/钛网骨水泥前方重建,并联合椎弓根钉内固定系统固定.随访观察手术时间、术中出血量、局部疼痛和脊髓功能的恢复情况,以及肿瘤复发、植骨融合、脊柱稳定性情况.结果:6例患者均顺利完成手术,手术时间200～270min,平均230min;失血量1100～3000ml,平均1400ml.随访6个月～3年,术后近期疗效均较满意,局部疼痛和神经症状均有不同程度改善或缓解.术前VAS评分平均8分,术后平均2分,平均下降6分;术前有脊髓神经功能障碍者中1例由Frankel B级恢复至D级,其余均恢复至E级.1例骨巨细胞瘤于术后15个月局部复发,再次手术;1例胃癌转移瘤患者术后14个月因多器官转移死亡;其余患者至末次随访时存活,植骨融合良好,无钛网移位及脊柱失稳,无断钉、断棒现象,无局部复发.结论:后路全脊椎整块切除术是胸腰椎肿瘤一种有效的手术方法,可改善脊髓神经功能,降低脊柱骨肿瘤局部复发率.     

前后联合入路一期全脊椎切除脊柱重建治疗颈胸交接部脊椎肿瘤

目的 探讨颈胸交接部脊椎肿瘤通过前后联合入路一期全椎切除脊柱重建治疗的可行性.方法 对8例颈胸交接部脊椎肿瘤选用改良的颈胸交接部前方入路及传统后方入路,一期行病椎全椎切除,脊柱重建方法.结果 术后1个月,除1例T2血管瘤神经功能A级恢复至C级,其余患者为E级(3例E级术后未加重).结论 选用改良的颈胸交接部前方入路及传统后方入路,一期行病椎全椎切除、椎体间植骨、前后联合固定重建脊柱,为治疗颈胸交接部脊椎肿瘤的一种可行方法.     

一期后路全脊椎切除术治疗多椎节脊柱肿瘤

目的 :探讨一期后路全脊椎切除术治疗多椎节脊柱肿瘤的安全性和有效性。方法 :回顾性分析2009年11月~2015年9月因多椎节脊柱肿瘤于我院行全脊椎切除术(total en bloc spondylectomy,TES)且资料完整的9例患者,男8例,女1例;年龄42.0±13.7岁(24~64岁)。原发肿瘤5例,其中骨巨细胞瘤2例,恶性神经鞘膜瘤、造釉细胞瘤、间叶源性肿瘤各1例;转移性肿瘤4例,其中肾癌、肝癌、前列腺癌、脂肪肉瘤各1例。记录手术时间、术中出血量、输血量、并发症、住院天数、术前及术后疼痛程度、神经功能情况。术后随访观察肿瘤是否复发、远处转移以及患者存活情况。结果:9例患者均成功接受一期后路多椎节全脊椎切除术,其中2椎节切除6例,3椎节2例,4椎节1例。手术时间8.9±2.8h(7~16h)、术中出血量3422.2±1342.4ml(1700~6000ml)、输血量2200.0±842.6ml(1000~4000ml)、住院时间31.1±20.3d(14~73d)。3例患者术中硬膜撕裂,1例胸膜破裂,3例患者术后出现胸腔积液,1例4椎体切除患者术后出现胸腔感染,无神经、大血管损伤等严重并发症。围手术期无死亡病例。1例患者随访期间出现钛网下沉,其他无内固定并发症。术后VAS评分(0.9±1.1分)较术前(7.1±1.2分)明显下降(P0.05)。术前脊髓神经功能5例ASIA分级为E级,术后仍为E级;3例术前D级,2例恢复至E级,1例仍为D级;1例术前C级,术后恢复至D级。9例患者均得到随访,随访时间29.8±15.2个月(12~61个月),随访期内6例患者局部无肿瘤复发,另3例患者分别于术后8个月、18个月、28个月时发现手术部位局部肿瘤复发。4例死亡,其中3例因全身多发转移死亡,1例死于肿瘤复发引起的并发症,中位生存期为34.75个月。结论:一期后路全脊椎切除术治疗多椎节脊柱肿瘤仍是高风险、高难度手术,但是可以术后即刻改善患者生活质量,需严格把握手术指征。     

寰椎后弓环抱钩连接枢椎椎弓根螺钉治疗寰枢椎不稳

目的探讨寰椎后弓环抱钩连接枢椎椎弓根螺钉治疗寰枢椎不稳的可行性及其临床疗效。方法 2009年6月—2013年12月,本院收治寰枢椎不稳患者22例,采用寰椎后弓环抱钩连接枢椎椎弓根螺钉手术治疗,其中男15例,女7例;年龄24~86岁,平均52.2岁。其中17例有不同程度的脊髓受压。术前Frankel分级B级3例,C级4例,D级10例,E级5例。术前日本骨科学会(Japanese Orthopaedic Association,JOA)评分为(9.82±0.80)分。术后定期观察内固定物的可靠性及植骨融合情况。结果所有患者均获随访,随访6~12个月,平均9个月。所有患者植骨融合良好。术后JOA评分(14.59±1.22)分,与术前相比有明显改善。术前Frankel分级B级3例,术后恢复至C级、D级各1例;术前C级4例,术后恢复至D级2例,E级1例;术前D级10例,术后恢复至E级3例。结论寰椎后弓环抱钩连接枢椎椎弓根螺钉内固定系统,术中操作安全简便、复位固定可靠、植骨融合率高,可作为现有寰枢椎内固定系统的有效补充。     

前、后联合入路全脊椎切除附加内固定治疗颈椎骨肿瘤39例报告

目的探讨对颈椎骨肿瘤采用前后联合入路全脊椎切除、内固定重建技术的疗效及其预后。方法1998年10月至2003年10月,对39例颈椎(C3-7)骨肿瘤患者实施全脊柱切除术。其中原发性骨肿瘤34例,包括骨巨细胞瘤14例,浆细胞瘤6例,神经鞘瘤(侵及椎体)1例,软骨肉瘤4例,骨母细胞瘤4例,恶性神经鞘瘤2例,动脉瘤样骨囊肿2例,脊索瘤1例;转移性肿瘤5例,原发灶来源于甲状腺癌、前列腺癌各2例,肺癌1例。经前后联合入路行单椎节切除29例、双椎节切除7例、3个椎节切除3例。经一期或二期前后联合入路行肿瘤切除与内固定重建。前路采用钛网植骨加AO、Orion、Zephir或者Codman等带锁钢板内固定,后路Cervifix、AXIS内固定重建。结果术后随访6个月至5年,绝大多数患者术后近期疗效较满意,局部疼痛和神经症状均有不同程度改善或缓解,19例脊髓神经功能完全恢复。1例术后出现一过性瘫痪加重,1例恶性神经鞘瘤术后1年局部复发,1例转移癌患者于术后25个月因全身衰竭死亡。结论全脊椎切除能显著降低颈椎原发性骨肿瘤局部复发率,改善脊髓神经功能,提高手术疗效。     

后外侧入路全脊椎切除重建术治疗胸椎骨肿瘤

目的探讨胸椎骨肿瘤后外侧入路全脊椎切除方式、重建技术及其疗效。方法25例胸椎骨肿瘤患者实施后外侧入路全脊椎切除重建术。经胸椎后外侧入路行单椎节切除22例、双椎节切除3例,均采用Harms钛网植骨/钛网骨水泥联合TSRH/MOSS/CDHM8椎弓根钉内固定系统重建。结果随访3个月~6年,23例术后近期疗效较满意,局部疼痛和神经症状均有不同程度改善或缓解;21例脊髓神经功能完全恢复;1例术后出现一过性瘫痪加重;3例分别于术后1~3年局部复发;术后12和18个月各死亡1例。结论胸椎后外侧入路全脊椎切除能显著降低胸椎骨肿瘤局部复发率,改善脊髓神经功能,提高手术疗效。钛网植骨/钛网骨水泥联合椎弓根螺钉系统能有效重建脊柱的前后柱稳定,同时具有减少创伤、缩短手术时间、降低并发症的优势。     

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.     

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.     

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.     

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.