腓骨近端截骨术联合关节镜清理治疗膝关节内侧间室骨关节炎的疗效

目的比较腓骨近端截骨术联合关节镜清理与单髁关节置换术(UKA)治疗膝关节内侧间室骨关节炎的疗效。方法选取2014年1月至2015年1月在本院接受手术治疗的膝关节内侧间室骨关节炎患者36例(36膝),依患者自主意愿选择手术方式后分为2组:截骨术组(17例)行腓骨近端截骨术联合关节镜清理,UKA组(19例)行UKA。术后1、3、6、12个月返院随访,采用Lysholm评分、牛津膝关节评分(OKS)、膝关节损伤和骨关节炎结果评分(KOOS)评估关节活动度和关节功能,影像学随访评价假体情况、骨溶解及感染等并发症。结果两组患者年龄、性别、体质量指数、关节炎分级(均为Ⅲ~Ⅳ级)等无差别。UKA组手术时间和住院时间长于截骨术组,术中出血量及术后引流量多于截骨术组(P0.05)。36例患者均得到随访,平均随访时间12.5个月。两组患者末次随访时Lysholm评分、OKS评分、KOOS评分均较术前明显改善(P0.05)。两组患者Lysholm评分、OKS评分、KOOS评分与术前比较的改善程度无差异(P0.05)。结论腓骨近端截骨术联合关节镜清理与UKA治疗膝关节内侧间室骨关节炎的近期疗效无差异,腓骨近端截骨术联合关节镜清理是一种值得推广的术式。     

股骨远端V行截骨和关节镜手术治疗膝外翻并骨性关节炎

目的：探讨联合应用股骨远端V行截骨和关节镜手术治疗膝外翻并骨性关节炎的价值。方法：2007年1月～2012年12月共收治25例外侧膝关节骨关节炎患者，其中11例应用关节镜手术和股骨远端V行截骨进行治疗，14只进行关节镜手术治疗。术后进行13～46个月的随访，采用Lysholm膝关节功能评分标准进行评分。结果：股骨远端V行截骨操作容易，易于调整矫形幅度。术后1年无矫形幅度丧失。术后1年，联合应用关节镜手术和股骨远端V行截骨进行治疗的患者，Lysholm评分为（95．26±2．47）分，只做关节镜手术的患者为（65．64±3．36）分。统计学分析表明，两组之间评分差异具有显著性意义（P〈O．05）。结论：联合应用关节镜手术和股骨远端V行截骨治疗外侧膝关节骨关节炎是更为有效的方法，股骨远端v行截骨是一种较为理想的截骨方法。     

胫骨内侧高位截骨联合关节镜下清理术治疗膝内侧单间室骨关节炎

目的 探讨采用胫骨内侧高位截骨联合关节镜下清理术治疗膝内侧单间室骨关节炎的疗效。方法 对22例膝内侧单间室骨关节炎患者先行关节镜下清理术,再予以胫骨内侧高位截骨。采用Lysholm评分评价疗效。结果 患者均获得1年随访。切口均一期愈合,术后8周胫骨截骨处基本愈合。术后半年及1年均采用Lysholm膝关节功能评分评价疗效:术后半年优19例,良2例,可1例,优良率21/22;术后1年优18例,良2例,可2例,优良率20/22。结论 胫骨内侧高位截骨联合关节镜下清理术治疗膝内侧单间室骨关节炎可以有效改善患者膝关节症状,是一种简单、安全的手术方法。     

关节镜联合开放楔形胫骨高位截骨术治疗膝关节骨关节炎的早期效果

目的 分析关节镜结合胫骨高位截骨术((high tibial osteotomy, HTO)治疗膝关节骨关节炎的早期效果。方法　选取2018年6月至2019年6月绵阳市中心医院骨科收治的因膝关节骨关节炎接受关节镜联合胫骨高位截骨术的患者88例(88膝)患者。收集评价患者美国特种外科医院膝关节评分(hospital for special surgery knee score, HSS)、视觉模拟评分(visual analogue scale,VAS)、手术前后下肢全长下X线片胫股角(femorotibial angle, FTA)、胫骨近端内侧角(medial proximal tibial angle, MPTA)等指标,并进行分析。结果　全部患者均得到随访,随访时间6~18月,平均12月。患者HSS评分术前(57.46±4.87)分、术后(79.19±2.48)分、术后1月(81.52±3.97)分逐渐增加,VAS评分术前(4.03±0.82)分、术后(2.52±0.50)分、术后1月(1.00±0.81)分逐渐降低,差异有统计学意义(P＜0.05)。FTA术前(179.72±2.30)°纠正至术后(172.81±1.36)°, MPTA术前(83.35±1.61)°纠正至术后(88.47±7.16)°,差异有统计学意义(P＜0.05)。结论　关节镜联合胫骨高位截骨术治疗膝关节骨关节炎早期在下肢力线及疼痛改善方面能取得较为满意效果。但其膝关节软骨恢复情况等需要进一步长期随访研究。     

关节镜下清理并胫骨高位截骨、腓骨近端切除术治疗内侧间室骨性关节炎

目的探讨应用关节镜下清理并胫骨高位截骨、腓骨近端切除术治疗内侧间室膝关节骨性关节炎的可行性。方法笔者自2014-05—2014-12应用关节镜下清理并胫骨高位截骨、腓骨近端切除术治疗10例内侧间室膝关节骨性关节炎,对比术前与术后9、18个月HSS评分及Lysholm评分差异。结果 10例均获随访15~20个月,平均18个月。胫骨截骨处术后1.5个月均获得临床愈合,2~3个月均获得骨性愈合,膝关节疼痛缓解明显,术后18个月HSS评分、Lysholm评分与术前、术后9个月比较差异均有统计学意义(P0.05)。结论应用关节镜下清理并胫骨高位截骨、腓骨近端切除术治疗内侧间室膝关节骨性关节炎,无需钢板内固定,不用异体骨,临床疗效满意。     

计算机导航胫骨高位截骨联合关节镜的短期疗效

目的观察计算机导航辅助下胫骨高位截骨(HTO)联合关节镜治疗胫骨内翻畸形的临床疗效。 方法本回顾性研究收集了2018年11月至2019年1月在上海长海医院接受治疗的20例膝内翻畸形合并内侧间室骨关节炎的患者,男性7例,女性13例。纳入标准：膝关节内侧间室骨关节炎,症状局限于膝内侧;膝关节内翻畸形,且胫骨近端内翻畸形。排除标准：膝关节外侧间室骨关节炎;外侧半月板损伤或有手术史;膝关节屈曲挛缩>10°;严重肥胖。手术方式为计算机导航辅助下开放楔形胫骨高位截骨联合关节镜手术。测量术前、目标及术后的机械胫股角(mTFA)、胫骨近端内侧角(MPTA)、关节线会聚角(JLCA),测量术前及术后的Lysholm评分及美国特种外科医院(HSS)膝关节评分,进行配对t检验及Mann-Whitney U检验。 结果本组20例患者,平均年龄(55±7)岁,平均随访(11±3)个月。术后mTFA、MPTA、JLCA及力线位置均较术前显著改善。术后Lysholm评分与HSS评分均高于术前[67(60,75) vs. 51(46,61)(Z＝-4.22,P<0.001),67(59,71)vs. 55(49,59)(Z＝-3.64,P<0.001)];术后mTFA、力线位置、矫正角度及撑开高度与术前规划目标无差异统计学意义(P>0.05)。关节镜探查发现6例患者伴有内侧半月板撕裂(其中2例患者为内侧半月板后脚根部撕裂),5例存在内侧肥厚或纤维化的滑膜皱襞,4例股骨内侧髁明显骨赘增生,均予以相应处理。 结论计算机导航辅助下胫骨高位截骨能获得与术前力线矫正计划一致的精确性;关节镜探查时处理关节内半月板、滑膜及骨赘增生等病理性改变,改善内侧间室的局部环境,是提高胫骨高位截骨术疗效必要的操作。     

关节镜下清理胫骨高位截骨骑缝钉固定术治疗膝骨关节炎

[目的]探讨关节镜下清理及应用记忆合金骑缝钉固定的胫骨高位截骨术治疗膝关节骨关节炎的手术方法、手术适应证及疗效。[方法]自1999年3月~2003年5月应用记忆合金骑缝钉固定的胫骨高位截骨术结合关节镜下清理术治疗膝关节骨关节炎34例(42膝),男6例(8膝),女28例(34膝),年龄42~67岁(平均54.2岁)。随访1 a 4个月~3 a 8个月(平均2 a 11个月)。关节镜下发现:髌内侧滑膜皱襞10例;内侧半月板损伤12例;外侧半月板损伤6例;关节软骨损伤20例;关节内游离体7例;髁间窝狭窄9例,关节镜下清理后进行胫骨高位截骨,不显露腓总神经,闭合楔形截骨,行改良胫骨结节前置,保持内侧骨膜的稳定性,应用记忆合金骑缝钉固定。[结果]膝关节疼痛基本消失,关节功能基本不受影响,膝内翻畸形得到矫正。膝关节评分术前为(53.71±6.7),术后为(91.02±7.7),两者比较有显著性差异(P<0.01),优良率为95.24%。术后并发症少,能早期进行功能锻炼,无需再次取出内固定。[结论]关节镜下清理及应用记忆合金骑缝钉固定的胫骨高位截骨术治疗膝关节骨关节炎,治疗关节内病变,具有操作简便,固定牢固,神经、血管损伤发生率低,可早期负重,早期进行功能锻炼,促进骨质愈合,组织相容性好,无须二次手术取出等优点。     

膝关节周围截骨术治疗膝关节骨关节炎

膝关节骨关节炎(KOA)的手术治疗方式有多种,膝关节周围截骨术作为可保留膝关节的一种术式,近来逐渐受到重视,尤其是对年轻、活动量较大的患者,可有效缓解骨关节炎症状,并为后期可能的膝关节置换等手术保留一定骨量。膝关节周围截骨术包括胫骨近端内侧开放楔形截骨术、胫骨近端外侧闭合楔形截骨术、股骨远端内侧闭合楔形截骨术、股骨远端外侧开放楔形截骨术、腓骨上段截骨术等,适用于治疗不同类型的KOA。该文就近年膝关节周围截骨术治疗KOA研究进展作一综述。     

胫骨高位闭合截骨联合关节镜手术治疗膝关节内侧骨关节炎5年以上随访

目的:探讨联合应用胫骨高位闭合外翻截骨和关节镜手术治疗膝内翻及内侧间室骨关节炎的价值。方法:自2005年10月至2007年6月,对25例符合纳入标准的内侧膝关节骨关节炎的患者,通过关节镜手术和胫骨高位闭合外翻截骨进行治疗。男11例,女14例,平均年龄53岁。术前HSS功能评分平均67.6±2.8,股骨胫骨角平均(185.54±1.11)°,胫骨近端外侧解剖角平均(96.54±0.52)°。术后采用HSS膝关节功能评分标准进行评分,并通过测量股骨胫骨角及胫骨近端外侧解剖角评估矫形效果。结果:手术均成功,没有严重并发症。所有患者获随访,时间为5~7年。术后1年HSS功能评分85.5±3.7,较术前提高(t=-33.135,P=0.000);末次随访HSS功能评分80.3±5.4,较术后1年降低(t=-13.215,P=0.000)。术后1年股骨胫骨角平均(173.65±0.92)°,较术前降低(t=28.739,P=0.000);末次随访股骨胫骨角平均(174.34±0.53)°,较术后1年提高(t=2.331,P=0.048)。术后1年胫骨近端外侧解剖角平均(87.32±0.33)°,较术前降低(t=37.264,P=0.000);末次随访平均(87.67±2.82)°,较术后1年提高(t=2.469,P=0.039)。结论:严格掌握适应证是保证疗效的前提,精确的手术技术是保证疗效的关键。术前计划和术中的力线观察对于保证手术成功至关重要。联合使用关节镜技术可同时处理关节内病变,关节内病变的清理和下肢力线的改善共同保证术后良好的疗效。术后骨关节炎的进展仍然在继续,但非常缓慢,中期疗效仍较满意。胫骨高位闭合外翻截骨是治疗单纯内侧膝关节骨关节炎的理想方法。     

闭式针锯截骨和关节镜手术治疗伴有内翻的膝骨性关节炎

[目的]探讨联合应用胫骨近端闭式针锯截骨和关节镜手术治疗伴有内翻的膝骨性关节炎的疗效。[方法]对17例伴有内翻的膝骨性关节炎的患者，通过关节镜手术和胫骨近端闭式针锯截骨，外固定器固定治疗。[结果]术前Lysholm评分为（43．2&#177;8．5）分，术后1年为（78．5&#177;9．5）分，术后2年（7例）为（91．6&#177;6．4）分。[结论]本手术方法是治疗伴有内翻的膝骨性关节炎的～种有效方法，胫骨近端闭式针锯截骨是一种较为理想的截骨方法。     

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.     

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.