髋臼内壁截骨术在发育不良髋关节全髋置换髋臼重建中的应用

目的探讨髋臼内壁截骨术在发育不良髋关节髋臼重建中的应用。方法2001年5月至2002年12月,采用结合髋臼内壁截骨术的全髋关节置换术治疗髋关节发育不良患者17例18髋,男1例1髋,女16例17髋,年龄35～70岁,平均51.4岁。其中CroweⅠ期4髋,Ⅱ期7髋,Ⅲ期4髋,Ⅳ期3髋。通过在手术前、后X线片上绘制Ranawat三角,对照手术前、后髋关节旋转中心与理想旋转中心的距离,测量术后臼杯穹顶与Kohler线的距离、臼杯直径等研究髋关节旋转中心重建与臼杯固定的效果。结果所有人工臼杯均安置于真臼位置,臼杯直径44～56mm,平均50.78mm。术前股骨头中心距理想旋转中心水平距离为12～40mm,平均21.09mm;术后股骨头中心距理想旋转中心水平距离为-3～10.1mm,平均3.73mm;手术前、后比较差异有统计学意义(t=7.95,P<0.01)。术前股骨头中心距理想旋转中心垂直距离为5～32mm,平均15.39mm;术后股骨头中心距理想旋转中心垂直距离为-18～26.3m m,平均4.98mm;手术前、后比较差异有统计学意义(t=3.42,P<0.01)。随访3个月以上者,截骨部位均骨性愈合。结论内壁截骨术有助于将发育不良髋关节的髋臼安置于真臼位置,保留髋臼底部的骨量,避免髋臼外上方植骨的并发症。     

髋臼内壁内移截骨全髋置换治疗髋关节发育不良髋关节旋转中心重建的病例对比分析

目的通过临床病例的对比分析研究,探讨髋关节发育不良的患者行全髋置换时,髋臼内壁内移截骨术和传统术式在恢复髋关节旋转中心方面的作用。方法将笔者行传统全髋置换术治疗的髋关节发育不良11例(传统术式组),与文献报道张洪行髋臼内壁内移截骨全髋置换17例(髋臼内壁内移截骨组)进行对比,通过在骨盆正位X线片上绘制Ranawat三角获得髋关节理想旋转中心,测量手术前、后实际股骨头旋转中心距理想旋转中心的水平和垂直距离,探讨两种术式在全髋置换髋臼重建时恢复髋关节旋转中心方面的作用。结果传统术式组术前水平距离为8～58mm,平均25.92mm,术后为6～34mm,平均16.46mm,手术前后比较有统计学差异(t=3.802,P0.01);术前垂直距离为4～38mm,平均20mm,术后为2～36mm,平均18.46mm,手术前后比较有统计学差异(t=2.589,P0.05)。两组手术前后水平距离差值的平均值分别为17.36mm、8.81mm,髋臼内壁内移截骨组大于传统术式组,有统计学差异(t=2.56,P0.05);两组手术前后垂直距离差值的平均值分别为10.41mm、3.47mm,髋臼内壁内移截骨组大于传统术式组,有统计学差异(t=2.27,P0.05)。结论传统术式有恢复髋关节旋转中心的作用;在恢复髋关节旋转中心作用上,髋臼内壁内移截骨术优于传统术式。     

成人髋关节发育不良髋臼和Harris窝解剖特征及在全髋置换术中旋转中心重建的意义

目的 观察成人髋关节发育不良(DDH)终末期骨关节炎髋臼和Harris窝的解剖学特征,探讨复原Harris窝和确定髋臼中心的方法,以准确安装髋臼假体,恢复髋关节旋转中心。方法自2005年3月至2011年2月,对42例(48髋)成人髋关节发育不良终末期骨关节炎施行人工全髋置换术(THA),其中男6例6髋,女36例42髋。年龄27~62岁(平均45岁);术前拍摄标准骨盆平片确定Crowe分型,其中CroweⅠ型6髋,Ⅱ型11髋,Ⅲ型20髋,Ⅳ型11髋。采用后外侧入路显露髋臼,观察髋臼和Harris窝的解剖学特征,清除覆盖于Harris窝表面的骨赘,复原出Harris窝和髋臼切迹,并以此为标志确定髋臼中心,磨削髋臼,安装髋臼假体。术后拍摄骨盆平片测量髋关节旋转中心的垂直距离和水平距离,评价旋转中心恢复效果。结果 48例成人DDH髋臼呈浅杯形、浅盘形、贝壳形、三角形四种基本病理类型,Harris窝根据骨赘覆盖程度不同呈现出裂隙状、三角状、封闭状、浅平状四种病理类型;根据复原Harris窝及髋臼切迹,确定髋臼中心并安装髋臼假体,手术前后骨盆前后X线片对比髋关节旋转中心:髋关节旋转中心垂直距离术前(37.8±5.2)mm,术后(13.7±2.4)mm,差异有统计学意义(P<0.05)。髋关节旋转中心水平距离术前(41.6±6.3)mm,术后(24.4±4.7)mm,差异有统计学意义(P<0.05)。结论 在成人DDH终末期骨关节炎髋臼和Harris窝因脱位程度和骨赘增生程度不同呈现出不同的病理类型,清除覆盖于Harris窝表面的骨赘可以复原出Harris窝和髋臼切迹,以复原后的Harris窝和髋臼切迹为标志确定髋臼中心,安装髋臼假体,可以准确地恢复髋关节旋转中心。     

全髋置换术中髋臼内陷的处理

目的探讨人工全髋关节置换术中髋臼内陷的处理方法及早期疗效。方法 2006年7月至2012年12月,收治继发性髋臼内陷症21例28髋,男12例17髋,女9例11髋;年龄26~68岁,平均56.3岁;原发疾病:类风湿关节炎9例14髋,强直性脊柱炎6例8髋,感染4例4髋(结核和化脓性关节炎各2例2髋),髋臼骨折畸形愈合2例2髋;轻度髋臼内陷6髋、中度髋臼内陷12髋、重度髋臼内陷10髋。患者均行人工全髋关节置换,术中单纯植入生物型臼杯6髋,打压植骨后直接植入生物型臼杯18髋,直接植入骨水泥杯2髋,打压植骨后骨水泥杯固定2髋。结果术后21例28髋切口均一期愈合,无感染及下肢深静脉血栓形成等并发症发生。患者均获随访,随访时间12~78个月,平均42个月。末次随访时,髋关节Harris评分为(87±4.1)分,术前Harris髋关节评分平均(45±3.3)分,较术前有显著差异,优22髋,良6髋,优良率100%。臼杯平均外翻角(42±3.5)°。植骨均骨性融合,无臼杯再次内陷及松动。髋关节活动度增加:屈曲增加(64.3±4.5)°,外展增加(20.5±3.5)°,内旋增加(16.5±2.5)°,外旋增加(19±2.5)°。末次随访时X线片显示所有假体均获得骨性稳定。术前股骨头内陷3~30 mm,平均13 mm;术后股骨头内陷0~5 mm,平均2 mm。人工股骨头旋转中心外移3~28 mm,平均10.5 mm。假体位置良好,无松动、下沉,植骨与髋臼融合,无髋臼再次内陷。结论人工全髋关节置换治疗髋臼内陷时,恢复患髋股骨偏心距及髋臼旋转中心,可获满意早期疗效。     

髋关节发育不良的髋臼重建

目的　总结采用全髋关节置换术治疗髋关节发育不良继发骨关节炎和功能障碍的经验。方法　 1998年 4月至 2 0 0 2年 4月 ,对 96例 112髋 (双侧 16例 )成人髋关节发育不良继发骨关节炎患者进行了全髋关节置换术。其中 ,半脱位 73髋 ,低位脱位 18髋 ,高位脱位 2 1髋。髋臼侧均采用真臼位置重建 ,其中骨水泥固定 16髋 ,非骨水泥固定 96髋 ,植骨 11髋 ;采用常规置换 83髋 ;磨削加深髋臼后 ,安置小号髋臼假体 2 7髋 ;髋臼外上缘自体股骨头植骨加深髋臼后 ,安置小号髋臼假体 2髋。结果　患者术后伤口均一期愈合 ,未发生感染或血管神经损伤 ,患肢长度平均延长 1 7cm。随访 85例 98髋 ,平均随访 3 5年 ,关节疼痛缓解 ,活动功能满意 ,Harris评分由术前的平均 33 9分恢复到平均 89 3分 ,无假体松动和翻修病例。X线片显示 ,关节假体位置正常 ,人工髋臼的平均外展角4 4° ,宿主骨对臼杯的平均覆盖率为 96 6 % ,金属臼杯与宿主髋臼之间未见透光线 ;11髋髋臼侧植骨病例中 ,植骨块与宿主骨愈合良好 ,未见骨吸收现象。结论　全髋关节置换术是治疗髋关节发育不良继发骨关节炎患者的有效方法 ;术前应充分考虑髋关节发育不良的原发及继发性病理改变 ,尽可能在真臼位置重建髋臼     

全髋关节置换术治疗成人髋关节发育不良的髋臼重建

目的探讨全髋关节置换术治疗成人髋关节发育不良（DDH）时不同方式髋臼重建对疗效的影响。方法 2000年1月至2007年10月,36例（44髋）先天性髋臼发育不良患者进行了全髋关节置换。年龄42～65岁,平均48岁。术前Harris评分平均为49.9分,双下肢长度差异平均为1.8 cm,髋关节平均活动度：屈曲59.6°,外展21.6°,内收13.9°,外旋10°,内旋8.2°。术中臼杯均安装于真臼处,髋臼内移14髋,髋臼内陷成形术18髋,自体股骨头结构性植骨12髋。髋臼侧均选用非骨水泥型假体。疗效评价：根据Harris评分分为优、良、可、差四级。结果所有患者均获得随访,随访时间1.8～9.2年,平均5.1年。平均Harris评分由术前的49.9分恢复到术后的90.1分,两者比较有统计学差异（P〈0.01,t=28.807）,其中评定为优23髋、良17髋、可4髋,术后优良率达90.9%。术后髋关节平均活动度：屈曲105°,外展35°,内收15.8°,外旋45°,内旋15°。本组病例无肺栓塞、深静脉血栓形成、感染等并发症发生。X线检查示假体无松动移位,无翻修病例。结论全髋关节置换术治疗成人髋臼发育不良采用恰当的髋臼重建结合非骨水泥型髋臼假体可获得满意中远期疗效。     

成人先天性髋臼发育不良全髋置换术中髋臼重建

目的探讨全髋关节置换治疗成人先天性髋臼发育不良术中髋臼的重建方法。方法对24例32髋成人先天性髋臼发育不良继发骨性关节炎患者进行了全髋关节置换术,21髋行自体股骨头及髂骨移植重建髋臼,11髋单纯行髋臼加深重建髋臼。术后以Harris评分、放射学改变、步态、肢体长度、Trendelenburg征评定治疗效果。结果所有患者均获得随访,时间6个月~5年。Harris评分由术前平均48.2分恢复到术后平均86.4分,X线片显示,自体股骨头及髂骨移植重建髋臼病例所有移植骨块均愈合良好。旋转中心平均下降55mm(37~69 mm)。29髋疼痛消失,3髋术后有轻微疼痛。1例术后Trendelenburg征持续阳性。结论根据术前评估,选择合适的髋臼重建方法进行全髋关节置换对成人先天性髋臼发育不良可获得较好疗效。     

CroweⅣ型髋关节发育不良全髋关节置换术前计算机辅助设计

目的 探索采用计算机辅助技术,对接受全髋关节置换(total hip arthroplasty,THA)的CroweⅣ型髋关节发育不良患者进行术前评估,确定髋臼大小、骨缺损程度,并在此基础上辅助手术设计、假体选择及骨缺损修复.方法 2011年3月至10月,共10例(13髋)CroweⅣ型高位脱位髋关节发育不良患者接受THA治疗.患者均为女性;年龄32～74岁,平均42岁.所有患者术前行髋关节三维CT扫描,然后将扫描数据输入Superlmage软件重建骨盆及髋臼.重建后在不同角度精确评估真臼位置,测量真臼大小及前后柱厚度,评估骨缺损程度;将髋臼试模、骨缺损修复材料(钽金属垫块)按1:1大小扫描输入计算机系统,进行术前模拟安放,确定髋臼假体大小、安放位置;髋臼假体安放后评估遗留的骨缺损,确定骨缺损修复材料,进行骨缺损修复模拟测试.结果 9例(12髋)术中实际安放髋臼假体型号与术前计算机辅助设计一致,1例(1髋)假体型号较术前设计大一号.所有患者髋臼安放位置与术前计划一致,均安放于真臼.髋臼骨缺损修复按术前设计:4髋因髋臼顶部骨缺损明显(臼顶部骨性覆盖＜70％),采用钽金属垫块修复骨缺损,以增强髋臼的稳定性;7髋采用Harris法自体股骨头植骨修复骨缺损;2髋髋臼杯植入后臼顶覆盖可,术中未植骨.结论 对CroweⅣ型髋关节发育不良者行计算机辅助下THA术前设计,有助于术前精确评估真臼发育情况、大小及髋臼骨缺损,提高手术治疗精确性.     

非骨水泥臼杯加自体股骨头植骨全髋关节置换术治疗髋臼发育不良伴骨性关节炎

目的：评价非骨水泥臼杯加自体股骨头植骨的全髋关节置换术治疗髋臼发育不良继发骨性关节炎的结果。方法：回顾性分析20例(21髋)患者行全髋关节置换术治疗髋臼发育不良继发骨性关节炎。女性18例,男性2例,平均年龄50岁,采用非骨水泥臼杯加自体股骨头植骨螺钉固定重建髋臼侧。臼杯置于真性髋臼水平,所有病例由于髋臼缺损而需要行自体股骨头植骨。平均植骨块覆盖的臼杯比例为31％(10％～45％)。8髋植骨块覆盖小于25％,13髋位于25％-50％之间。平均随访时间4．7年(1．5—8年)。采用改良Harris评分对结果进行评估。术前及随访时进行摄片观察。结果所有植骨块均获得愈合。无植骨块塌陷和髋假体松动。改良Harris评分由术前平均46分增加到89分。术前除1例双髋发育不良外,下肢不等长均超过2cm,术后只有2例仍有双下肢不等长超过1cm。3髋的植骨块外侧非支撑臼杯部分出现轻微的骨吸收。3髋发现有BrookerⅠ度异位骨化,1髋Ⅱ度异位骨化。结论：使用非骨水泥臼杯加自体股骨头植骨重建髋臼侧的全髋关节置换术治疗髋发育不良继发骨性关节炎可获得良好结果。该方法在植骨块支撑臼杯不超过50％的情况下,髋臼固定可靠,可保留髋臼的骨量。     

CroweⅢ型发育性髋关节发育不良全髋关节置换术中臼杯高位和解剖位安放的临床疗效对比分析

目的:探讨在CroweⅢ型发育性髋关节发育不良全髋关节置换术中非骨水泥臼杯适度高位安放和解剖位安放的临床疗效对比。方法:回顾性分析2010年1月至2015年12月,46例(58髋)CroweⅢ型髋关节发育不良患者全髋关节置换术中臼杯高位安放(高位安放组),选择2004年1月至2009年12月行全髋关节置换中自体股骨头结构性植骨髋臼解剖位重建的CroweⅢ髋关节发育不良患者(解剖位安放组)20例(28髋)作为对照。高位安放组男6例(8髋),女40例(50髋);年龄40～70(54.3±7.6)岁。解剖位安放组男4例(5髋),女16例(23髋);年龄42～68(53.0±7.1)岁。比较两组手术时间及出血量,术后Harris评分、步态、Trendelanburg征及下肢长度差,影像学测量结果,假体生存率有无差异。结果:高位安放组手术时间为(75.1±13.3) min,出血量为(108.4±47.1) ml;解剖位安放组手术时间为(107.7±17.1) min,出血量(210.0±58.6) ml;高位安放组的手术时间和出血量均小于解剖位安放组。术后2年随访时高位安放组HHS评分为92.3±3.7,解剖位安放组Harris评分为91.4±3.6,两组差异无统计学意义。双下肢长度高位安放组(3.8±2.1) mm,解剖位安放组(3.5±1.6) mm,两组差异无统计学意义。术后高位安放组旋转中心距泪滴连线的垂直距离(31.6±7.8) mm,解剖位安放组(19.3±7.4) mm,解剖位安放组小于高位安放组;水平距离高位安放组(30.1±7.7) mm与解剖位安放组(29.4±7.5) mm比较差异无统计学意义。两组假体生存率差异无统计学意义。随访期间所有患者步态良好,无外展肌效力不足导致的跛行或Trendelanburg征阳性。结论:CroweⅢ型发育性髋关节发育不良全髋关节置换术中生物型臼杯适当高位并内移安放术后短期随访患者功能好、假体生存率高,因此臼杯高位安放是CroweⅢ型发育性髋关节发育不良髋臼重建的一种有效方法。     

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.     

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.     

Immunomodulation in Transplantation with Photopheresis

Abstract: Photopheresis is a technique in which peripheral blood mononuclear cells, in the presence of a photoacti-vatable compound, are exposed extracorporeally to ultraviolet A light and reinfused, inducing a host autoregula-tory immune response. Experimental work and ongoing clinical studies are helping to define the role of this novel, safe, and non-toxic immunomodulating technology in the field of transplantation.