腰椎棘突劈开椎管减压术治疗退变性腰椎管狭窄症

目的:总结腰椎棘突劈开、椎管减压术治疗腰椎管狭窄症的优缺点及手术疗效。方法:2008年4月～2009年4月采用棘突劈开、椎管减压术治疗退变性腰椎管狭窄症28例,男16例,女性12例;年龄40～71岁,平均63.1岁;病程0.3～10年,平均8.5年。单节段6例,双节段18例,3节段4例;L3/4 20例,L4/5 28例,L5/S1 6例,9例合并腰椎间盘突出。术前单侧下肢麻木、疼痛者22例,双侧6例。步行距离10～1000m,平均315m。术前JOA评分10.3±1.4分,腰痛、下肢痛及下肢麻木VAS分别为4.6±0.7分、7.7±1.0分和6.1±2.3分。术后第3天行血肌酸激酶(CPK)测定。术后定期随访患者症状改善情况和影像学改变。结果:手术时间65～175min,平均115±5.6min,术中失血量50～500ml,平均116±12.5ml,单、双及3节段平均显露时间分别为11.3±2.0min、20.2±2.6min及26.1±2.1min。术后第3天CPK为336±16.1u/L。术后3个月随访时,1例劈开棘突因缝合不当未完全愈合,其余患者劈开棘突均一期愈合。随访16～36个月,平均25.3个月,末次随访时JOA评分24.7±3.5分,改善率为(77.0±3.1)%,腰痛、下肢痛及下肢麻木VAS分别为1.6±0.7分、1.1±0.3分及2.5±1.3分,均较术前显著改善(P<0.05)。未出现腰椎不稳,多裂肌无明显萎缩。结论:棘突劈开椎管减压术能保护双侧多裂肌,有效减少术后腰痛,是治疗退变性腰椎管狭窄症的有效方法。     

椎板成形术治疗原发性胸腰椎椎管内肿瘤临床分析

目的 分析椎板回植成形术在原发性胸腰椎椎管内肿瘤切除手术中的价值.方法 原发性胸腰椎椎管内肿瘤患者21例,术中切断双侧椎板,保留双侧关节突,完整取下棘突椎板复合体,显微镜下摘除肿瘤后将棘突椎板复合体原位回植.并用椎弓根螺钉固定,丝线修复棘突间韧带.术后椎管矢状径、椎板融合率、日本骨科学会(Japanese orthopaedic association,JOA)评定进行效果评定.结果 椎管内肿瘤成功切除,未出现脑脊液漏,无顽固性下腰痛,术后1年JOA评分由术前(11.4±2.6)分上升至(24.7±3.3)分,差异有统计学意义(P＜0.05),术后优良率达82.5％,术前椎管矢状径为(13.5±1.5)mm,随访6月后术后椎体CT显示椎管矢状径为(16.4±2.4)mm,术后1年椎板骨性融合率90.48％.结论 原发性胸腰椎椎管内肿瘤切除手术中,椎板回植成形术法重建了脊柱的解剖结构,维持了术后脊柱的稳定性.     

巨大型腰椎间盘突出症的手术治疗

目的探讨巨大型腰椎间盘突出症手术治疗的效果。方法28例巨大型腰椎间盘突出症患者中,8例行单侧扩大开窗减压髓核摘除,6例行双侧开窗减压,6例行后路半椎板切除减压髓核摘除,8例行后路全椎板切除减压髓核摘除;28例均行椎弓根螺钉固定。16例行椎间自体髂骨植骨,12例行cage椎间植骨术。单侧椎间植骨融合14例,双侧椎间植骨融合14例。应用JOA评分评价患者手术前后及随访时的神经功能,观察植骨融合情况。结果2例硬脊膜撕裂,1例出现单侧神经根麻痹。JOA评分由术前(11.85±2.41)分提高到术后(25.34±3.23)分,优良率为83.78%。其中单侧开窗组评分由术前(11.60±2.30)分术后改善到(24.85±3.30)分,优良率83.06%;双侧开窗组由术前(11.50±2.40)分术后改善到(25.50±3.20)分,优良率81.12%;半椎板切除组由术前(11.71±2.34)分术后改善到(25.83±3.41)分,优良率86.36%;全椎板切除组由术前(11.92±2.53)分术后改善到(24.49±3.19)分,优良率80.00%。患者均获随访,时间18～66个月,随访期内26例获得骨性融合,融合率...     

开窗减压术和椎板切除减压术治疗腰椎管狭窄症的对比分析

[目的]比较双侧椎板间开窗减压术和保留棘突韧带复合结构目的全椎板切除减压术治疗以中央椎管狭窄为主目的腰椎管狭窄症目的疗效,并介绍保留棘突韧带复合结构目的全椎板切除减压术目的手术方法.[方法]10年间手术治疗有间歇性跛行症状目的以中央椎管狭窄为主目的腰椎管狭窄症患者93例;其中用舣侧椎板间开窗减压术治疗62例(开窗组),用保留棘突韧带复合结构目的全椎板除减压术治疗31例(保棘组).获随访82例(其中开窗组54例,保棘组28例),平均随访4年.以术后间歇性跛行足否消失做为减压是否充分目的标准,以术后遗留活动性腰痛做为术后腰椎不稳目的标准.[结果]开窗组术后间歇跛行消失40例(74.1%),残留活动性腰痛5例(9.3%).保棘组术后间歇性跛行消失23例(82.1%),残留活动性腰痛3例(10.7%).x2检验P值＞0.05.[结论]在对中央型腰椎管狭窄症[目的]减压果和对腰椎稳定性目的影响上开窗组和保棘组无统计学差异.两者目的减压效果均良好,对腰椎稳定性影响小.但保留棘突韧带复合结构目的全椎板切除减压术术野开阔、操作简单、不易损伤神经,是值得推荐目的手术方法.     

改良棘突椎板复合体回植在治疗原发性椎管内肿瘤中的应用

目的探讨改良棘突椎板复合体回植治疗原发性椎管内肿瘤的方法及疗效。方法对21例原发性椎管内良性肿瘤患者采用改良棘突椎板回植治疗,术中保留一侧棘上棘间韧带,摘除肿瘤后将带蒂棘突椎板复合体原位回植,双侧微型钛板固定。术后根据影像学检查评估椎管容积、椎板愈合情况及有无移位。结果手术时间80~140(120±15)min,术中出血量150~500(250±35)ml。所有患者肿瘤切除完整,切口愈合良好。患者均获得随访,时间12~36个月。患者均椎板固定牢靠,无移位,无继发椎管容积减小,回植椎板16例双侧骨愈合,5例单侧骨愈合。术后1年JOA评分由术前(12.4±2.6)分上升至(23.4±3.5)分。结论改良棘突椎板复合体回植治疗原发性椎管内肿瘤对重建脊柱的解剖结构及维持术后脊柱的稳定性疗效显著。     

微创单侧入路双侧减压治疗腰椎椎管狭窄症早期疗效观察

目的评估微创单侧入路双侧减压经椎间孔椎体间融合术治疗腰椎椎管狭窄症的短期疗效？方法2010年6—10月,38例腰椎椎管狭窄症患者接受开放或微创手术治疗,微创组17例,开放组21例。记录手术时间、术中出血量和引流量、术后住院时间、并发症情况以及手术前后的腰痛视觉模拟量表（visualanalogscale,VAS）评分及日本骨科学会（Japanese Orthopaedic Association,JOA）评分。结果平均随访7．6个月。微创组平均出血量较少,手术时间较长,而术后住院时间较短。2组患者术后腰痛及功能均有显著改善,微创组末次随访时腰痛VAS评分低于开放组,微创组术后、随访时JOA评分及JOA改善率均明显高于开放组。微创组患者并发症发生率略高于开放组但差异无统计学意义（P〉0．05）。结论微创单侧入路双侧减压结合微创经椎间孔椎体间融合术治疗腰椎椎管狭窄症短期疗效满意,其长期疗效有待进一步随访明确。     

棘突椎板截骨回植椎管潜行扩大减压治疗腰椎管狭窄症

目的探讨棘突椎板截骨回植椎管潜行扩大减压治疗腰椎管狭窄症的临床效果。方法 2007年1月至2010年1月对28例腰椎管狭窄症患者,采用经棘突椎板截骨将椎管后部结构整块取下,潜行扩大椎管,处理完椎管内病变后再将后部结构原位回植固定。术前术后进行影像学观察及JOA疗效评分对比。结果 28例均获得随访,CT显示椎管矢状径术前平均为(13.5±2.5)mm,术后平均为(16.8±2.6)mm。JOA评分术前平均为(5.8±1.5)分,末次随访时平均为(23.2±2.0)分。术后6～14个月复查CT示椎板原位融和率为100%,未发现腰椎不稳和椎管再狭窄。结论棘突椎板截骨回植椎管潜行扩大减压术具有椎管显露充分、椎管后部结构完整保留、脊柱稳定性好、瘢痕黏连压迫硬脊膜及神经根发生率低等优点,是治疗腰椎管狭窄症一种行之有效的方法。     

单侧入路双侧减压治疗高龄腰椎管狭窄症的疗效观察

目的 :观察与分析高龄腰椎管狭窄患者行单侧入路双侧椎管减压术的临床疗效。方法 :回顾性分析2017年3月～2019年9月收治的因腰椎管狭窄症采用有限性椎管减压手术的35例75岁以上的高龄患者,依据手术方式分为传统后正中入路双侧椎板开窗椎管减压术组(A组,n=17,男7例,女10例,平均年龄80.1±3.8岁)及单侧入路双侧有限性椎管减压术组(B组,n=18,男10例,女8例,平均年龄79.9±3.7岁)。观察比较两组患者的手术时间、术中出血量,并采用VAS疼痛评分、JOA评分评估手术疗效。结果:A、B两组间的患者基本情况比较无统计学意义;两组均顺利完成手术。与A组相比,B组患者的手术时间(61.9±17.6min vs 50.4±14.3min)更短,术中出血量(62.6±24.7ml vs 45.4±20.3ml)更少,其差异均具有统计学有意义(P0.05)。与术前相比,两组患者术后12个月腿痛VAS评分明显下降,JOA评分明显升高,差异均有统计学意义(P0.05),A、B两组间的比较无统计学意义(P0.05)。术后12个月两组患者的腰痛VAS评分较术前改善不明显(P0.05)。所有患者术后均未发生脊柱不稳定。结论:单侧入路双侧减压治疗高龄腰椎管狭窄症可以获得与开放手术相同疗效,具有时间短、术中出血少、创伤小、不破坏腰椎稳定性的优点。     

两种不同方法置入Dynesys内固定的早期临床对比研究

目的比较单侧剥离半椎板切除潜行对侧扩大减压联合对侧经多裂肌间隙行Dynesys内固定与双侧剥离全椎板切除Dynesys内固定治疗退行性腰椎椎管狭窄症的早期临床效果和安全性。方法 2010年2月～2011年3月27例退行性腰椎椎狭窄患者（43个节段）行Dynesys内固定手术。15例（24个节段）行症状重侧单侧剥离半椎板切除,潜行对侧扩大减压,对侧经多裂肌间隙安装Dynesys内固定;12例（19个节段）行双侧暴露全椎板切除减压安装Dynesys内固定。通过对患者术前术后疼痛视觉模拟量表（visual analog scale,VAS）评分和腰背、下肢Oswestry功能障碍指数（Oswestry disability index,ODI）,摄正侧位和动力位X线片,记录手术切口,术中术后出血量比较2种方法的临床效果和安全性。结果 27例患者得到8～20个月的随访。2组患者对比研究显示单侧剥离组的手术切口、肌肉创伤、术中出血量、术后引流量及术后初次腰痛评分改善程度优于双侧暴露安装组。影像学资料显示2组患者椎间隙前高、后高及椎间孔高度、面积均较术前明显增加。2组患者椎间隙前高、后高和椎间孔高度、面积改变量及术后节段活动度改变量差别不大。结论单侧剥离半椎板切除潜行对侧扩大减压联合对侧经多裂肌间隙行Dynesys内固定同样可以达到足够的减压效果;与双侧剥离全椎板切除减压Dynesys内固定相比,具有创伤小,术中、术后出血少,术后初次腰部疼痛评分优于后者等优点。     

精准减压与全椎板切除减压手术治疗腰椎管狭窄症的疗效对比

目的探讨全椎板切除减压手术与精准减压手术治疗腰椎管狭窄症(lumbar spinalstenosis,LSS)的疗效优劣。方法收集我院2013-09-2015-09行减压手术治疗的LSS患者76例,依据手术方式将其分为两组:其中行全椎板切除减压手术41例,作为对照组;行精准减压手术治疗35例,作为观察组。对两组患者术后随访2年以上,对比其围手术期指标,以及术前、术后2年的VAS评分、ODI指数和多裂肌损伤情况。结果 (1)与对照组相比,观察组的手术时间较短,术中出血量较少,且术后住院时间明显缩短(P0.05)。(2)术后2年时,两组患者腰痛、腿痛VAS评分与ODI指数均获显著改善(P0.05),但观察组术后的腰痛VAS评分显著优于对照组(P0.05)。(3)两组术前的多裂肌MRI信号等级无显著差异(P0.05);但观察组术后3级损伤仅占比14.29%,显著低于对照组的34.15%,差异有统计学意义(P0.05)。结论与全椎板切除减压手术相比,精准减压手术治疗LSS患者的减压效果可靠,可减少术中出血量、缩短住院时间,减轻术后多裂肌的损伤,较好地保留了脊柱后柱结构的完整性。     

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.     

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.     

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.