应用假体翻修大段异体骨保肢失败后的功能重建

目的探讨应用组合式假体翻修大段异体骨感染或骨折的疗效。方法回顾性研究了美国迈阿密大学医学院和中山大学附属第一医院骨肿瘤科共22例肩关节或膝关节周围肿瘤的患者,大段异体骨保肢失败后,应用肿瘤型假体重建肢体功能。最初诊断包括骨肉瘤11例、软骨肉瘤4例、恶性纤维组织细胞瘤3例、骨巨细胞瘤2例、恶性血管内皮瘤1例和鼻咽癌转移瘤1例。发病部位包括股骨远端15例、肱骨近端3例和胫骨近端4例。结果异体骨失败原因包括:骨折14例、感染6例、持久不愈合1例、合并骨折和感染1例。异体骨移植后平均随访154.2(63～293)个月,假体翻修后平均随访73.4(24～234)个月。90.9%(20/22)的患者最终肢体功能良好,MSTS功能评分为76.5%(60%～93.3%)。81.8%(18/22)的患者假体翻修手术成功,在翻修失败的患者中,1例肱骨近端肿瘤患者为了改善功能经历了多次翻修手术,另1例股骨远端的患者,异体骨移植失败假体翻修后,由于假体近端松动而进行二次翻修——全股骨置换术,另外2例股骨远端的患者翻修后合并感染和骨折而截肢。结论异体骨重建因骨折或感染失败后,再次行假体翻修重建肢体功能是可靠的,并发症较低。翻修技术会影响重建肢体的功能。对于异体骨感染的患者,建议分期翻修重建肢体功能。     

胫骨下段大段瘤性骨缺损修复重建的研究进展

目的对胫骨下段大段瘤性骨缺损的修复重建方式进行综述。方法查阅国内外胫骨下段大段瘤性骨缺损重建方式的相关文献,从保留踝关节术及非保留踝关节术两方面进行总结分析。结果对于胫骨下段大段瘤性骨缺损的修复重建,除了常规的同种异体骨移植、带血管自体腓骨移植、同种异体骨复合带血管腓骨移植、瘤段灭活回植、牵张成骨及骨搬运技术外,临床已逐渐开始应用膜诱导成骨技术、人工肿瘤干假体、3D打印金属骨小梁假体、踝关节融合术、人工肿瘤踝关节置换术。另外,因胫骨下段恶性肿瘤患者生存期较长,骨缺损修复重建后的功能恢复也受到越来越多关注。结论胫骨下段大段瘤性骨缺损修复重建方式已获得长足进步,但对于最佳方式仍存在争议。随着近年来3D打印技术及各类术前模拟技术的出现,个性化、精准化修复重建胫骨下段大段瘤性骨缺损成为可能,需要进一步探讨研究。     

数字骨库的建立及其在骨肿瘤手术治疗中的应用

目的 建立数字化骨库,并探讨其在骨肿瘤切除同种异体骨重建中的临床应用价值.方法 采用薄层CT对现有骨库中的大段同种异体骨进行扫描,将所得断层数据输入自制的数字骨科管理软件,三维重建后建立数字化分析系统.利用数字化骨库找到匹配的骨重建材料,并在术前设计截骨范围和异体骨修整.2009年11月至2012年6月对11例骨肿瘤患者采用数字化骨库和计算机辅助导航技术进行手术治疗,男7例,女4例;年龄13 ～42岁,平均24.7岁;其中骨巨细胞瘤3例,骨肉瘤5例,软骨肉瘤2例,尤文氏肉瘤l例.术后复查患处X线片并采用肌肉骨骼肿瘤学会93(MSTS93)评分系统评价肿瘤学结果和功能恢复情况. 结果 应用数字化骨库可以明显缩短异体骨材料的选配时间,并明显提高异体骨选配的精确性.使用计算机辅助导航进行肿瘤切除大段同种异体骨重建,术前CT三维虚拟影像与实际解剖注册点匹配满意,注册误差平均为0.42 mm.11例患者术后随访3～30个月,平均15.7个月;术后复查影像可见肿瘤切除范围与异体骨重建区域与术前计划完全吻合,肿瘤切除范围安全,边界完整,无肢体不等长或畸形发生;未见局部复发和远隔转移,无内固定松动、断裂和关节塌陷,无明显免疫排异反应;异体骨与宿主骨愈合时间5～7个月,平均6.3个月.MSTS93功能评分平均为25.7分. 结论 建立的数字化骨库可在术前精确选择同种异体骨并完成手术设计,结合计算机辅助导航技术可实现骨肿瘤切除、大段同种异体骨重建的个体化设计,可有效提高骨肿瘤手术治疗的安全和疗效.     

基于快速成型技术的个体化人工股骨髁关节面的设计与应用

目的设计、制造一种基于快速成型技术、复合异体半关节移植的个体化人工股骨髁关节面,探讨解决异体半关节移植中异体关节软骨坏死和异体-自体关节形状不匹配的方法。方法对异体半关节和骨肿瘤患肢股骨髁外表面行螺旋CT扫描,将CT断层图像进行矢量转换后在Surfacer 9．0软件进行矢量化三维重建,提取出合适的异体骨软骨下骨和患者关节软骨表面轮廓的三维图像,在计算机辅助下设计人工关节面,应用LPS600快速成型机制出快速成型树脂模型,以钛合金为材料铸造关节面假体主件,通过融合笼将关节面固定于关节上,抛光后获得人工关节软骨面成品。2002年2月对1例男性14岁右股骨下段骨肉瘤患者,行右股骨下段瘤段切除、人工股骨髁关节面复合大段同种异体骨移植重建股骨下端骨缺损术。结果新型复合异体半关节移植的个体化人工股骨髁关节假体与异体骨、对侧关节匹配良好;应用后随访16个月,膝关节功能良好。结论个体化股骨髁关节面明显改善了异体半关节移植患者的膝关节功能,为异体半关节移植中存在的异体关节软骨坏死和异体一自体关节形状不匹配提供一种解决方案。     

肿瘤膝关节假体与大段同种异体骨重建治疗膝关节周围肿瘤疗效对比

目的探讨肿瘤型膝关节假体与大段同种异体骨复合带血管腓骨重建治疗膝关节周围肿瘤的手术适应证、临床疗效及并发症。方法回顾性分析2010年6月至2015年6月,在我中心行保肢手术并获得随访的膝关节周围肿瘤患者共51例,其中男28例,女23例;年龄7～61岁,平均(17.8±1.2)岁。骨肉瘤37例,尤文肉瘤12例,骨巨细胞术后复发1例,软骨肉瘤Ⅱ级1例。累及股骨远端31例,胫骨近端20例。接受肿瘤型膝关节假体置换33例,病变位于股骨20例,胫骨13例;接受大段异体骨复合带血管腓骨重建18例,病变位于股骨11例,胫骨7例。结果本组51例患者均获随访,随访时间47～71个月,平均(58.0±3.0)个月。14例(27.5%)死亡,23例(45.1%)术后出现了肺转移,3例(5.9%)局部复发,6例(11.8%)出现术后感染,5例(9.8%)无瘤存活。用美国骨骼肌肉系统肿瘤协会评分(mus-culoskeletal tumor society,MSTS),肿瘤型膝关节假体置换患者平均(24.5±2.1)分,异体骨复合带血管腓骨重建患者平均(26.1±1.7)分。结论保肢手术已经成为治疗膝关节周围恶性肿瘤的主要方式,肿瘤型膝关节假体是主要的重建方式,具有负重早、稳定性好、早期并发症低等优点。大段异体骨复合带血管腓骨重建,对于病变未明显累及骨骺,预期生存时间较长的患者具有一定的优势,但术后并发症较多,必须严格掌握适应证。     

定制型膝肿瘤假体的设计与临床应用

目的：总结分析定制型膝肿瘤假体的设计与临床应用经验。方法：回顾性分析1999年6月～2002年10月膝关节周围骨肿瘤41例。男29例，女12例；年龄11～69岁，平均35．0岁。股骨远段肿瘤32例，胫骨近段肿瘤9例。骨肉瘤15例，骨巨细胞瘤13例，软骨肉瘤3例，孤立性骨转移瘤5例，纤维肉瘤、恶性纤维组织细胞瘤、尤文氏瘤、小圆细胞肉瘤及韧带样纤维瘤各1例。于包膜外截除肿瘤段后置入定制的半制约式带股骨(或胫骨)膝关节假体，其中1例11岁患儿置入假体的股骨段有后期延长装置。1例患者术中行股动脉切除、大隐静脉移植修补术。结果：41例手术均顺利完成。随访时间超过8个月的33例平均随访20．2个月。所有患者均于术后3个月内恢复日常生活能力。术后肿瘤有2例局部复发，有3例远处转移。膝关节假体的设计保证膝关节在伸屈活动的同时，可适度的内外旋与内外翻，并保持关节稳定性；还为胫骨近段截除患者提供了效果较好的重建髌韧带止点的假体设计与手术方法，术后患者伸膝功能恢复满意。无假体松动、断裂等并发症。结论：定制型膝关节肿瘤假体为半制约式，只需定做有特殊需要的部件，其他部件选用预制的标准部件，这样有利于缩短定制周期、保证质量和降低费用，可作为股骨远段或胫骨近段肿瘤患者保肢治疗的方法之一。     

股骨干原发恶性肿瘤保肢手术中的重建策略

目的探讨股骨干原发恶性肿瘤保肢手术治疗及重建的方法,并分析其并发症及功能结果。方法回顾性分析2006年10月至2019年10月手术治疗并获得随访的37例股骨干原发恶性肿瘤患者资料,男22例,女15例;年龄(20.56±4.72)岁(范围:8～46岁)。37例Enneking恶性肿瘤分期均为ⅡB期,肿瘤病灶累及股骨长度范围10～24 cm,均未发生病理性骨折;术前行穿刺活检,病理确诊为骨肉瘤22例,软骨肉瘤8例,尤文肉瘤5例,恶性纤维组织细胞瘤2例。骨肉瘤与尤文肉瘤均行新辅助化疗。8例行人工全股骨假体置换术(置换组),14例行大段异体骨移植髓内钉内固定术(异体骨组),同种异体骨-假体复合物(allograft-prosthetic composite,APC)术8例(APC组),3D打印假体7例(3D打印组)。肢体功能按照世界骨与软组织肿瘤协会(Musculoskeletal Tumor Society,MSTS)93系统评分,对比分析各组之间肢体功能及优良率。结果 37例随访时间(23.15±16.74)个月(范围:6～62个月)。至末次随访,9例(30.76%)出现肺转移,其中6例患...     

数字化骨库的建立及在骨肿瘤切除异体骨关节个体化重建中的应用

目的探讨数字化骨库建立的可行性,评价异体骨数字化对于导航下骨肿瘤切除异体骨重建的影响。方法采用CT扫描的方法,对骨库深低温冷冻保存的同种异体骨段进行扫描,通过三维重建建立数字化分析系统（数字化骨库）。利用数字化骨库,选择最佳匹配的骨关节重建材料,数据导人计算机导航系统,标定骨肿瘤切除和异体骨段的截骨范围,依据术前设计在导航下实施、监测。2009年11月至2011年11月,采用数字化骨库和导航辅助切除重建技术对6例关节周围恶性骨肿瘤进行治疗,患者平均年龄（27．2±9．1）岁,其中骨肉瘤3例,软骨肉瘤2例,尤文氏肉瘤1例;Enneking分期：ⅡA期2例,1IB期4例,术后评价肿瘤学结果和功能恢复情况。结果与常规异体植骨材料术前准备操作相比,数字化骨库建立后,大大缩短了异体骨关节材料的选配时间,同时明显地提高了选配的精确性。计算机导航辅助下进行肿瘤切除、异体骨关节切割以及关节力线监控,术中解剖注册点与CT三维虚拟影像匹配满意,注册误差（0．42±0．17）mm。术后影像显示肿瘤整块切除范围和异体骨关节截骨区域与术前计划完全一致,关节重建稳定,无肢体不等长和关节畸形。随访（19．3±0．7．1）个月,未见局部复发和远隔转移,无明显免疫排异反应,异体骨与宿主骨平均愈合时间（5．2±0．8）个月,无内固定松动、断裂和关节塌陷。MSTS93平均功能评分（26．2±4．1）分。结论数字化骨库的建立为术前选配同种异体骨材料提供了精细可靠的信息,结合计算机辅助导航,可以实现骨肿瘤切除异体骨关节重建的个性化设计要求,进一步提高保肢手术的安全性和效果。     

四肢恶性骨肿瘤功能重建后的并发症防治

目的分析四肢恶性骨肿瘤功能重建后并发症的发生原因与防治。方法自2002年9月至2004年12月共有22例患者接受保肢治疗。年龄10～63岁，平均26.3岁。男10例，女12例。其中骨肉瘤15例，恶性骨巨细胞瘤2例，软骨肉瘤5例。15例骨肉瘤患者术前均接受了2～3次化疗。待伤口愈合后再接受5～6次化疗。肿瘤部位：胫骨近端5例，股骨远端12例，股骨近端1例，股骨中段2例，肱骨近端2例。手术方法为局部肿瘤完整切除，大段异体骨移植术、人工假体重建术和肿瘤灭活再植术。其中10例行人工假体重建术，10例行大段异体骨移植术，2例行肿瘤灭活再植术。结果随访7～27个月，3例骨肉瘤患者术后局部复发，复发时间分别为术后3个月、7个月、1年，后行截肢术。1例患者术后3个月出现肺转移，经化疗后肺部肿块消失；2例大段异体骨移植术患者术后出现排斥反应，伤口不愈伴感染，后经清创、腓肠肌肌皮瓣转移术后愈合。1例人工假体重建术后2周，伤口出现渗液，后经局部换药后愈合。结论恶性骨肿瘤采取保肢的术后并发症与适应证的选择、肿瘤对化疗的敏感性、瘤体切除的方式、功能重建选择的方法等都有密切的关系。因此，在对恶性肿瘤采取保肢手术治疗时，必须综合考虑上述因素，才能减少并发症的发生。     

肩胛带区骨肿瘤的保肢治疗

目的探讨肩胛带区骨肿瘤的保肢手术方法及相关的临床效果。方法35例肩胛带骨肿瘤患者,男24例,女11例,平均年龄34岁(12～74岁)。肿瘤部位:肱骨上段21例,肩胛骨12例,锁骨2例;肿瘤类型:骨肉瘤10例,软骨肉瘤7例,恶性纤维组织细胞瘤3例,尤文肉瘤3例,纤维肉瘤1例,骨髓瘤1例,骨巨细胞瘤7例,转移瘤3例。按照Malawer等提出的手术分类方法进行分类。保肢手术方法:肿瘤假体置换8例,瘤段骨灭活回植4例,异体骨关节移植3例,自体腓骨移植2例,髓针骨水泥假体置换1例,Tikhoff-Linberg手术3例,瘤段肢体切除、上肢短缩再植2例,全肩胛骨或关节盂切除、肱骨头悬吊4例,部分肩胛骨切除6例,锁骨瘤段切除2例,其中16例作了化疗。结果本组患者平均随访71个月(6～186个月),局部复发4例,远处转移6例,死亡9例,无瘤存活22例。按MSTS上肢功能评分标准,35例患者上肢功能评分平均为77%(40%～100%),上肢功能与手术切除范围密切相关。并发症:切口感染裂开4例,移植骨骨折2例,暂时性桡神经麻痹2例,肩关节半脱位3例。结论肩胛带区骨肿瘤的治疗应根据患者情况、肿瘤类型及侵袭范围等因素决定切除范围并选择应用肿瘤假体置换、自体或异体骨关节移植、瘤段骨骨灭活回植及Tikhoff-Linberg手术等重建方法,可以达到控制肿瘤、稳定无痛的肩关节重建和保留良好的肘部与手部功能的目的。     

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.     

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.     

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.     

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.     

Systemic analgesia adapted to the children's condition

A concept of balanced analgesia using nonsteroidal anti-inflammatory drugs (NSAIDs), paracetamol (acetaminophen), opioids, and corticosteroids can also be used in patients with pre-existing illnesses. NSAIDs are the most effective treatment for acute pain of moderate intensity in children; however, these drugs should be avoided in patients at increased risk for serious side effects, e.g. patients with renal impairment, bleeding tendency, or extreme prematurity. NSAIDs can be given with minimal risks to the younger child with mild to moderate asthma, and, in these patients, the use of steroids can be encouraged; in addition to their antiemetic and analgesic action, a beneficial effect on asthma symptoms can be expected. In the non-intubated child with cerebral trauma, exaggerated sedation caused by opioids and increased bleeding tendency caused by NSAIDs must be avoided. In neonates and small infants, the oral administration of sucrose or glucose is helpful to minimize pain reaction during short uncomfortable interventions.