保留耻骨前列腺韧带在耻骨后根治性前列腺切除术控尿中的作用

目的 探讨耻骨后根治性前列腺切除术中保留耻骨前列腺韧带(PL)的控尿作用.方法前列腺癌患者74例.年龄52～73岁,平均65岁.术前实验室检查PSA 2.0～23.6 ng/ml,平均16.5 ng/ml.其中64例行经直肠超声引导下前列腺系统穿刺活检,病理证实为前列腺癌;10例行TURP后病理发现前列腺癌.74例均行盆腔MRI及全身骨扫描未见前列腺外转移病灶.A期6例、B期68例.手术方法:常规行双侧盆腔淋巴结清扫,锐性切开盆内筋膜至PL侧缘,50例保留PL,在尿道前方紧贴前列腺尖部的弧形缘放置集束血管钳,控制耻骨后血管复合体(包括PL与背静脉复合体);对照组24例紧贴耻骨切断PL,在尿道前方紧贴前列腺尖部的弧形缘放置集束血管钳,控制背静脉复合体.在集束钳下方用1-0可吸收线分别贯穿缝扎集束血管钳控制的组织,沿前列腺的弧形切断该束组织达前列腺尖部与尿道连接处.离断尿道.采用"网球拍"式的膀胱颈重建.整形后的膀胱颈与尿道黏膜对黏膜于2、5、7和10点分别吻合4针,将保留在复合体上的1-0缝线于重建膀胱颈的12点、距吻合缘0.5～1.0 cm处浆肌层贯穿缝扎,将其与复合体结扎固定.术后保留尿管2周.结果 74例手术均顺利.随访3～12个月.保留PL组及切断PL组年龄分别为(61.3±2.4)和(60.8±2.1)岁,实验室检查PSA分别为(14.3±1.2)和(14.7±1.3)ng/ml,手术时间为(110.5±10.4)和(109.7±10.6)min,术中出血量为(250.5±23.4)和(253.4±22.3)ml,切缘阳性率为6%(3/50)和8%(2/24);2组比较差异均无统计学意义(P>0.05).保留PL组与切断PL组术后拔除尿管不同时间的控尿率分别为:即刻26%(13/50)和0%(0/24),1个月时为50%(25/50)和12%(3/24),3个月时为80%(40/50)和42%(10/24),6个月时为96%(48/50)和67%(16/24),12个月时为100%(50/50)和75%(18/24);2组比较差异均有统计学意义(P<0.05). 结论 PL在耻骨后根治性前列腺切除术后控尿中发挥较大作用,术中应积极保留.     

个体化改良术式防止前列腺癌根治术后尿失禁

目的：探讨前列腺癌根治术中保护控尿功能的方法。方法：对51例临床局限性前列腺癌患者(TNM分期为T1a～3hN0M0)，采用个体化改良术式行耻骨后根治性前列腺切除术，术中为保留控尿功能仔细解剖前列腺尖部并作无张力膀胱颈一尿道残端吻合。结果：术后12～14d拔除尿管时22例(43．1％)控尿满意，术后1个月45例(88．2％)控尿满意．术后3个月至今，所有患者控尿满意。平均随访14个月(3～24个月)，随访期间无生化复发及尿道狭窄发生。结论：术中注意以下几点可提高耻骨后根治性前列腺切除术后的控尿功能：①良好控制背静脉丛以获得无血手术视野；②在保证尖部切除范围前提下，尽量延长功能性尿道长度；③根据术中具体解剖情况再造膀胱颈口；④膀胱黏膜外翻并与尿道残端无张力吻合(7针或9针缝合法)，减少术后漏尿及尿道狭窄发生。     

耻骨后根治性前列腺切除术10年体会

目的:总结近10年来100例耻骨后根治性前列腺切除术的经验和教训。方法:1999年7月至2009年7月笔者行耻骨后根治性前列腺切除术100例,对其中84例随访3~120个月,统计术前年龄、PSA,术中输血量、手术时间,术后尿控能力、阴茎勃起功能,吻合口狭窄情况和最大尿流率。结果:患者平均年龄、PSA、输血量及手术时间分别为66.8岁、20.1 ng/ml、585.7 ml和198.9 min。术后3、6、12个月尿控分别为65.5%、81.7%和92.4%,术后12个月有42.2%恢复阴茎勃起功能,吻合口狭窄5例,最大尿流率平均20.5 ml/s,生化复发13例,死于前列腺癌1例。结论:耻骨后根治性前列腺切除术治疗局限性前列腺癌效果好,采用先结扎耻骨前列腺韧带和前列腺静脉丛后再离断耻骨前列腺韧带的方法有利于提高尿控能力,要得到术后好的阴茎勃起效果,应注意保护神经血管束和副阴部动脉,良好的尿道粘膜和膀胱粘膜对合可减少吻合口狭窄,对T3a或伴局部淋巴结转移患者术后外放疗可减缓生化复发。     

机器人辅助根治性前列腺切除术中血管神经束保留技术的疗效分析

目的探讨机器人辅助腹腔镜前列腺根治术中血管神经束保留的可行性。方法回顾分析我科于2014年3至7月对42例TNM分期为T1b~T2的前列腺癌患者采用筋膜内剥离血管神经束技术行经腹途径机器人辅助根治性前列腺切除术。技术要点:经筋膜内沿前列腺包膜锐性分离至前列腺尖部,保留尿道括约肌和尿道直肠肌;正确判断前列腺与膀胱颈交界部,保护膀胱颈环状肌环;横行离断膀胱颈后唇,在狄氏筋膜和膀胱肌外层之间向膀胱颈近端方向适当游离膀胱颈后唇;吻合后尿道与膀胱颈,将吻合口的前壁与耻骨后血管复合体固定。术后随访尿控及性功能恢复情况。结果 42例均手术成功,术中平均失血量80(50~210)ml。术后病理切缘均阴性。拔出尿管时间平均10d,术后尿漏2例。随访时间平均11(8~12)个月。术后3个月复查tPSA,均0.2 ng/mL。术后3、6个月控尿有效率分别为90%(38/42)和93%(39/42)。术后3、6个月,勃起功能评分:术前21分的31例分别为81%(25/31)、87%(27/31)。结论机器人辅助前列腺癌根治术经筋膜内保留血管神经束,在技术上是可行的;对前列腺周围解剖组织结构的完全性保留可加快患者术后尿控及性功能恢复,提高患者生活质量。     

腹腔镜根治性前列腺切除术中尿控功能保护的方法和手术技巧

目的探讨腹腔镜根治性前列腺切除术中尿控功能的保护,预防术后尿失禁的手术方法及技巧。方法对2008年10月至2012年6月施行的81例腹腔镜前列腺癌根治术资料进行回顾性研究。81例TNM分期为T1C～T2C的前列腺癌患者行腹腔镜前列腺癌根治术,其中经腹膜外径路15例,经腹腔途径66例。术中注重以下策略：①可靠处理背血管复合体;②尽量保留神经血管束,对部分低危患者施行筋膜内根治性前列腺切除术;③保留足够的功能性尿道;④黏膜对黏膜无张力吻合。所有患者于术后1、3、6和12个月随访尿控情况。结果术后留置导尿管7～23d。所有患者均随访满6个月,77例患者随访满12个月。术后6个月,白天62例（76．5％）患者尿控良好,尿失禁19例;夜间68例（84．0％）患者尿控良好,尿失禁13例。术后12个月,白天70例（90．9％）患者尿控良好,尿失禁7例;夜间74例（96．1％）患者尿控良好,仍有尿失禁3例。筋膜内根治性前列腺切除术5例,术后7～11d拔除导尿管后,仅1例白天有尿失禁,随访至术后3个月,已无一例存在尿失禁。随访期间无一例出现尿道狭窄。结论腹腔镜根治性前列腺切除术后的尿控功能恢复是渐进式的,绝大多数患者在术后12个月恢复尿控能力。术野清晰,努力做到解剖性前列腺切除,保留尽可能多的功能性尿道长度,黏膜对黏膜无张力吻合（避免术后尿道狭窄）,将膜部尿道缝合至趾骨后就能获得良好的尿控效果。对低危的前列腺癌患者施行筋膜内根治性前列腺切除术将能获得最佳尿控结果。     

经尿道前列腺等离子电切或内腺剜剥术对膀胱全切正位膀胱术的改良应用（附9例1年随访报告）

目的：探讨用先行经尿道前列腺等离子电切,或经尿道前列腺内腺剜剥术,保留部分前列腺被膜的方法.对根治性膀胱切除回肠正位膀胱术进行改良的应用价值.方法：分析2008年1月～2008年10月行该改良术式9例患者的临床资料.先行经尿道前列腺等离子电切或内腺剜剥术,再行膀胱切除,保留部分前列腺被膜,尽量保留背静脉复合体,不过多解剖盆底结构,保留双侧神经血管束及精囊,前列腺被膜腔与＂W＂回肠膀胱无张力吻合.随访手术效果及生活质量.结果：6例行经尿道前列腺等离子电切,3例行内腺剜剥术,背静脉复合体5例仅缝扎未离断,2例缝扎并离断,2例未予处理.手术时间300～390 min,失血300～1 000 ml.均为移行细胞癌,残端（一）,G1、G2各4例,G3 1例;T1N0M01例;T2N0-1M0 7例,T3N0M0 1例.1例术后1个月死亡.8例无瘤生存至今12～19个月,最大尿流率平均19.2 ml/s,白日完全尿控6例,不完全尿控2例;夜间尿失禁1例;IIEF-5评分平均16.6.结论：选择合适病例,可试用经尿道前列腺等离子电切或内腺剜剥术,对根治性膀胱切除回肠正位膀胱术进行改良,以保留部分前列腺破膜,利于保护性神经和盆底尿控结构,并降低手术难度.经随访1年余,短期内未发现肿瘤种植转移复发.新膀胱出口无狭窄,勃起功能及尿控功能恢复较好.     

腹腔镜下耻骨后保留尿道前列腺切除术 技术成熟前后与经尿道前列腺等离子 电切术的临床比较

目的 探讨技术成熟后腹腔镜下耻骨后保留尿道前列腺切除术的可行性及临床价值。方法收集本院2013年1月至2016年12月住院的大体积（＞80 mL）良性前列腺增生(benign prostatic hyperplasia,BPH)患者的临床资料,按照设定的入选及排除标准共有104例患者入组。研究分为三组,A组：2013年1月至2014年12月行腹腔镜下耻骨后保留尿道前列腺切除术的患者22例;B组：2013年1月至2016年12月行经尿道前列腺等离子电切术（transurethral plasmakinetic resection of the prostate, PKRP）的患者57例;C组：2015年1月至2016年12月行腹腔镜下耻骨后保留尿道前列腺切除术的患者25例。记录每组患者年龄、前列腺体积、国际前列腺症状评分（IPSS）、残余尿测定（RUV）、最大尿流率（Qmax）,术中手术时间、出血量;术后膀胱冲洗时间、留置尿管时间、住院时间;术后3个月IPSS评分、RUV、Qmax,最后对结果进行统计学分析。结果 ①早期腹腔镜下耻骨后保留尿道前列腺切除术手术时间长、术中出血多,技术成熟后可明显缩短手术时间,减少术中出血量;②该手术成熟后在不延长手术时间的前提下,术后3个月疗效与TPKRP相当;③该手术与TPKRP相比,可以缩短膀胱冲洗时间、拔管天数以及术后住院天数。结论 成熟的腹腔镜下耻骨后保留尿道前列腺切除术是治疗大体积（＞80 mL）BPH安全有效的方法。     

耻骨后前列腺癌根治术的技术改进(附32例报告)

目的　改进耻骨后前列腺癌根治术的手术技术 ,减少并发症。　方法　临床诊断为T1和T2 期前列腺癌患者 32例 ,平均年龄 6 8岁。改进耻骨后前列腺癌根治技术 ,包括广泛盆腔淋巴结清扫、保护神经血管束、缝扎背深静脉、多保留尿道后壁组织、膀胱尿道吻合时的膀胱颈部套叠等。　结果　手术时间平均 3.5h ,术中平均出血量 4 5 0ml,输血 1 7例。术后病理报告 :肿瘤局限于包膜内者30例 ,切缘阳性 1例 ,盆腔淋巴结转移 1例。随访 8～ 4 8个月 ,平均 2 2个月 ,均存活。PSA <1ng/ml者2 8例 ,1～ 3ng/ml者 4例。术后 3～ 6个月患者均恢复完全控尿。术后恢复勃起功能者 1 0 / 1 8(5 6 % )例。　结论　耻骨后前列腺癌根治术可有效切除肿瘤、保护控尿功能、保留性功能 ,是局限性前列腺癌的首选治疗方法。     

C.R.P.C.四步法腹腔镜根治性前列腺切除术的安全性和疗效分析

目的探讨经腹膜外途径C.R.P.C.四步法腹腔镜根治性前列腺切除术治疗局限性前列腺癌的安全性和疗效。方法回顾性分析2015年4月至2017年12月同济医院收治的102例前列腺癌患者的病例资料。年龄(67±5)岁。术前总PSA值(45.32±18.33)ng/ml。前列腺体积(42±12)cm^3。102例均行磁共振检查和前列腺穿刺活检确诊为前列腺癌,临床分期cT1c^cT3b期。102例均在全麻下行经腹膜外途径腹腔镜根治性前列腺切除术。术中采用C.R.P.C.四步法,即控制背深静脉复合体(control dorsal deep venous complex,C);识别前列腺膀胱交界面、精囊层面、狄氏间隙层面3个解剖层面(recognize three anatomical layers,R);保留尿道括约肌和膀胱颈(preserve urethral sphincter and bladder neck,P);连续行尿道吻合(continuous anastomosis between urethra and bladder neck,C),特别注意3、5、7、9点方向4针。记录手术时间、术中出血量、住院时间和术后并发症。结果本组102例手术均顺利完成。手术时间平均92(55~156)min。出血量平均105(55~185)ml。无中转开放手术。1例(0.98%)术前中度贫血患者(血红蛋白65 g/L)术后予输血治疗。病理检查结果显示15例(14.70%)切缘阳性。术后1周内2例(1.96%)发生尿外渗,经牵拉尿管并延长尿管留置时间后恢复正常。术后随访(26.4±3.5)个月。术后6个月11例(10.78%)出现PSA复发;术后12个月2例发生Ⅰ~Ⅱ度尿失禁,1例发生排尿困难。结论C.R.P.C.四步法腹腔镜根治性前列腺切除术易学易记,能够使初学者掌握根治性前列腺切除术的程序化手术操作步骤。本方法术后并发症少,肿瘤控制效果较好。     

改良的Madigan前列腺切除术

目的　对Madigan前列腺切除术 (MPC术 )进行改良 ,提高手术疗效。　方法　对 52例前列腺增生 (BPH)患者行MPC术 ,并进行手术改良。包括 :(1)显露膀胱颈及尿道起始部以避免或减少尿道损伤 ;(2 )联合膀胱顶部小切口以治疗中叶增生显著和 (或 )合并膀胱病变的BPH。结果　尿道完整或基本完整者 48例 ,术中出血较少 ,平均手术时间 12 0min。其中 3 5例获随访 ,随访时间 1～ 12个月 ,术后平均最大尿流率 18 9ml/s;8例患者手术前后行排尿期膀胱尿道造影 ,证实术后前列腺部尿道及膀胱颈完整 ,尿道较术前明显增宽。　结论　改良的MPC术减少了尿道损伤的发生 ,扩大了MPC术的适应证 ,手术操作简便、并发症少 ,疗效确切     

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.     

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.     

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.