后路全脊椎截骨术治疗先天性脊柱侧后凸畸形

目的评价后路全脊椎截骨术治疗先天性脊柱侧后凸畸形的临床效果。方法 2007年8月至2009年12月,采用后路全脊椎截骨术治疗先天性脊柱侧后凸畸形病例21例,男7例,女14例;年龄7～32岁,平均16.3岁;胸段19例,腰段2例;伴发脊髓纵裂7例,脊髓空洞1例,不全瘫3例。所有病例均行后路一期全脊椎截骨、矫形植骨融合固定术。测量术前、术后及随访时站立位全脊柱正侧位X线片,记录冠状面和矢状面Cobb角、顶椎偏移;记录术中出血量、手术时间及围手术期并发症。结果所有患者切口均一期愈合,随访时间16～38个月,平均22.4个月。本组病例手术时间平均为694.5min,术中出血量平均2429ml,冠状面Cobb角由82.9°矫正到36.0°,平均矫形率56.6%,矢状Cobb角由82.5°矫正到39.8°,平均矫形率51.8%,顶椎偏移由27.1mm矫正到11.1mm,矫正率59.0%。1例术后神经诱发电位示右胫后神经SEP降低,2周后恢复,无其他神经系统并发症,椎体间植骨病例随访时均获得融合,无内固定松动、断裂等并发症。结论后路全脊椎截骨椎体切除可直接去除致畸原因,在冠状面和矢状面上均可获得良好的矫形,并可获360°减压,是目前治疗先天性脊柱侧后凸畸形较为有效的方法。     

后路半椎体切除内固定矫治先天性脊柱侧后凸

目的评价后路一期半椎体切除椎弓根钉矫形治疗先天性半椎体所致脊柱侧后凸的临床效果。方法11例患者,平均年龄9.3岁,4例位于胸椎,5例位于腰椎,均为完全分节型,手术采用后路一期半椎体切除,椎弓根器械矫形并植骨融合。结果手术固定节段2-7个椎体,平均3.3个椎体。术后随访6-30个月,平均14.5个月。全脊柱正侧位X线片示冠状面Cobb角由术前平均41.15°矫正至15.35°,平均矫正率61.53％,矢状面Cobb角由术前平均34.15°矫正至13.26°,平均矫正率60.27％,顶椎偏移由术前25.34mm矫正至11.46mm,最后随访时侧凸和后凸Cobb角平均分别为16.86°和14.08°,与术后相比无纠正丢失。无任何手术并发症,无内固定断裂脱落,均融合。结论一期后路半椎体切除椎弓根器械矫形是治疗先天性脊柱侧后凸安全、有效的术式,能够获得满意的矫正。     

经后路多点锚定技术治疗Ⅰ型神经纤维瘤病伴营养不良性脊柱侧凸的临床疗效

[目的]探讨经后路多点锚定技术治疗Ⅰ型神经纤维瘤病伴营养不良性脊柱侧凸的临床疗效。[方法]回顾性研究2005年1月~2013年12月本科收治的Ⅰ型神经纤维瘤病伴营养不良性脊柱侧凸23例;年龄10~22岁,平均13.6岁;其中胸弯13例,胸腰双主弯4例,胸腰弯3例,双胸弯2例,腰弯1例;术前冠状面Cobb角48.9°~91.4°,平均68.3°;凸侧Bending相Cobb角40°~79.2°,平均57.4°;柔韧性8.3%~28.1%,平均15.7%;顶椎旋转度2°~3°,平均2.3°;矢状面胸椎后凸Cobb角46.4°~79.6°,平均58.2°,胸腰段后凸Cobb角21.1°~35.7°,平均28.3°。均采用经后路多点锚定技术进行矫形融合固定。[结果]随访12~96个月,平均52个月。术后冠状面Cobb角16.3°~46.7°,平均28.4°;顶椎旋转度1°~2°,平均1.2°;矢状面胸椎后凸Cobb角16.1°~38.3°,平均25.3°,胸腰段后凸Cobb角-4.3°~18.7°,平均8.9°;术后各指标均获得良好的矫正,侧凸矫正率为46.3%~74.1%,平均56.9%。末次随访时侧凸矫正丢失率仅3.1%,无神经系统并发症,仅1例假关节形成。[结论]经后路多点锚定技术治疗Ⅰ型神经纤维瘤病伴营养不良性脊柱侧凸可获得较满意的矫形融合效果。     

前路松解联合后路矫形固定治疗重度脊柱侧凸

目的：评价前路松解联合后路矫形对重度脊柱侧凸的治疗效果。方法：2000年7月至2007年1月采用前路松解联合后路矫形固定治疗重度脊柱侧凸23例,男12例,女11例;年龄9～18岁,平均15.3岁。其中先天性半椎体脊柱侧凸9例,特发性脊柱侧凸13例,神经纤维瘤病性脊柱侧凸1例。冠状面上Cobb角81°～126°,平均97.4°。结果：术后侧凸Cobb角为10°～55°,平均37.4°,平均矫正率56.2%。身高增加0.5～7.5cm,平均5.2cm。全部病例均获随访,时间6～24个月,平均10个月,2例出现交界区＂附加＂现象,无断棒、脱钩等并发症。结论：脊柱前路松解安全、有效,联合后路矫形内固定治疗重度脊柱侧凸可获得满意治疗效果。     

后路一期半椎体切除治疗胸腰椎多发半椎体脊柱畸形

目的：观察后路一期半椎体切除、内固定植骨融合术治疗胸腰椎多发半椎体脊柱畸形的临床效果。方法2005年6月至2012年12月南华大学附属第一医院收治9例胸腰椎多发半椎体畸形患儿,其中3例胸腰椎有3个半椎体畸形、6例有2个半椎体畸形,共计21个半椎体;完全分节型14个、不完全分节型7个。均行后路一期半椎体切除、内固定植骨融合术,术前、术后和定期随访时拍摄站立位脊柱正侧位片,测量冠状面侧凸Cobb角及矢状面后凸Cobb角。结果全部患者获随访7～52个月（平均24.8个月）。手术时间210～450 min （平均326 min）,术中出血量1200～3800 mL（平均1950 mL）。冠状面侧凸Cobb角由术前的（47±10）°矫正至术后的（14±4）°,矢状面后凸Cobb角由术前的（28±4）°矫正至术后的（11±4）°,手术前后比较,差异有统计学意义（P＜0.05）。末次随访时冠状面和矢状面矫形丢失不明显。1例术中出现硬脊膜撕裂致术后脑脊液漏,延长伤口引流时间后痊愈;1例术后出现神经根性分布一侧下肢麻木、胀痛,随访3个月症状消失。术后6个月随访9例患者均获得植骨融合,无一例发生感染、内固定失败及假关节形成。结论对于胸腰椎多发半椎体脊柱畸形,后路一期半椎体切除、内固定植骨融合术可取得良好的临床效果。     

肋骨结构性支撑植骨在脊柱侧凸前路矫形手术中应用的长期随访

[目的]评价肋骨结构性支撑植骨在青少年特发性脊柱侧凸前路矫形融合手术中应用的长期随访结果.[方法]回顾性分析术后随访时间超过4年的青少年特发性脊柱侧凸前路矫形手术病例30例,男3例,女27例;年龄12～ 17.5岁,平均14.3岁.侧凸类型包括PUMC Ⅰ b型5例、Ⅰc型5例、Ⅱd1型20例.全部病例均行前路矫形融合手术,植骨方式采用自体肋骨结构性支撑植骨.术前、术后及随访时摄脊柱站立位X线片,测量冠状面及矢状面Cobb角,并观察植骨融合情况,有无假关节形成及内置物并发症.[结果]随访4～10.2年,平均6.3年.融合弯冠状面矫形率术后平均为75.1％,末次随访时矫形丢失平均4.6°;固定融合节段冠状面矫形率术后平均为93.2％,末次随访时丢失平均2.1°;固定融合节段矢状面Cobb角术前与术后比较无显著性差异,末次随访时矫形丢失平均3.1°.13例胸腰段后凸患者术前后凸平均8.3°,术后矫正为前凸平均5.6°,末次随访时保持前凸平均3.7°.全部病例末次随访时均未见假关节形成或内置物并发症.[结论]肋骨结构性支撑植骨在青少年特发性脊柱侧凸前路矫形融合手术中能获得并维持良好的冠状面及矢状面矫形,且融合率高、远期矫形丢失少,是一种可靠、有效的植骨方法.     

后路松解楔形截骨矫治先天性胸腰段半椎体并重度僵硬性脊柱侧后凸畸形

目的:评价经后路松解楔形截骨矫治先天性胸腰段半椎体并重度僵硬性脊柱侧后凸畸形的安全性和临床初步效果,并探讨其融合固定节段的选择。方法:2007年4月～2010年3月收治先天性胸腰段半椎体并重度僵硬性脊柱侧后凸畸形患者11例,男4例,女7例,年龄14～22岁,平均17.1岁;半椎体均为单个完全分节型,T11 3例,T12 4例,L1 1例,L2 3例;术前侧凸Cobb角82°～125°,平均94.4°,侧凸柔韧性为17.4%～28.9%,平均24.8%;后凸Cobb角72°～145°,平均101.1°;C7铅垂线与骶正中线距离1.5～5.5cm,平均2.9cm。均行经后路松解楔形截骨矫形手术,以触及椎(touched vertebrae,TV)(指站立前后位像上被骶正中线触及的最近端椎体)作为融合固定下端椎;1例合并脊髓拴系和脊髓纵裂者,术中一期行骨嵴切除,解除拴系。结果:均顺利完成手术。平均松解3.0个椎间隙。手术时间5.5～10.0h,平均7.7h;术中出血量1000～7000ml,平均3500ml。无脊髓神经损伤。1例术中切除肋骨小头时引起左侧胸膜撕裂,发生血气胸,行胸腔闭式引流,2周后痊愈;1例术后出现螺钉穿破背部皮肤,1枚螺钉钉尾外露,术后3个月取出该枚螺钉。术后侧凸Cobb角7°～54°,平均28.0°,平均矫正率为70.9%;后凸Cobb角20°～36°,平均27.8°,平均矫正率为71.7%;C7铅垂线与骶正中线距离0.1～2.3cm,平均0.6cm,冠状位平衡平均矫正率为78.1%。随访14～35个月,平均23.4个月,末次随访侧凸Cobb角8°～57°,平均29.7°,丢失率为7.3%;后凸Cobb角22°～38°,平均29.9°,丢失率为7.7%;C7铅垂线与骶正中线距离0.2～2.5cm,平均0.7cm;随访X线片证实植骨均融合,内固定物无松动、断裂。选择TV作为远端融合椎(lowest instrumented vertebrae,LIV)比选择稳定椎(stable vertebrae,SV)平均节省了1.09个椎体,未发现失代偿现象。结论:经后路松解楔形截骨矫治先天性胸腰段半椎体并重度僵硬性脊柱侧后凸畸形安全有效,选择TV作为LIV可以减少融合节段。     

重度僵硬型脊柱侧凸的后路非全椎体截骨手术治疗

[目的]探讨重度僵硬型脊柱侧凸后路非全椎体截骨手术治疗的疗效。[方法]本组男18例,女24例,年龄13~32岁,平均19.2岁。术前冠状面Cobb角80°~135°,平均96.2°,矢状位Cobb角56°~102°,平均73.5°。均采用后路顶椎附近凹侧脊旁软组织、椎板间隙和小关节松解,再用直的短棒连接并强力撑开,矫正部份畸形,再分别在凹侧和凸侧进行双棒进一步矫形和固定。[结果]所有患者均安全完成手术,无神经脊髓损伤等严重并发症发生。术后随访12~60个月,平均36.5个月。术后冠状位Cobb角平均35.3°,矫正63.3%,最后一次随访时平均40.2°,矫正58.2%。术后矢状位Cobb角平均33.4,°矫正54.6%,最后一次随访时平均36.8°,矫正49.9%。[结论]对于椎体间无骨性融合的重度僵硬性脊柱侧凸,在充分松解的基础上,采用直的短棒强力撑开后再矫形,不需要全椎体截骨就能够获得满意的矫形效果,避免了截骨可能出现的并发症。     

胸椎楔形截骨术矫正胸段侧凸畸形

目的　探讨胸椎体楔形截骨在顶椎位于胸段脊柱侧凸矫形中的应用价值。方法　采用后路凸侧椎体楔形截骨、凹侧软组织松解、椎弓根系统内固定治疗胸段脊柱侧凸 2 3例 ,其中特发性脊柱侧凸畸形 2 0例 ,侧方半椎体畸形3例。共行截骨 2 9个椎体 ,T10 以上椎体截骨 14个 ,最高为T5椎体 ,T10 以下椎体截骨 15个。所有病例皆采用椎体冠状面楔形截骨。结果　术后随访平均 19.2个月 (4个月～ 36个月 )。术前Cobb角为 6 5°～ 110° ,平均为 74 .4°。术后测量的Cobb角为 10°～ 35° ,平均矫正率为 76 .5 % ;术后平均身高增长 4 .5cm。手术中失血为 80 0～ 82 0 0ml,平均170 0ml。术后皆无神经系统及其他方面的并发症。结论　单一后路椎体楔形截骨可有效矫正胸段脊柱侧凸     

经后路L1椎体截骨短节段椎弓根内固定术治疗脊柱后凸畸形

目的探讨L1椎体楔形截骨椎弓根螺钉内固定术矫治胸腰段脊柱后凸畸形的效果。方法56例胸腰段后凸畸形患者,均行经后路L1椎体截骨短节段椎弓根内固定,全部采用单节段截骨。结果本组平均手术时间3．7（2．8～4．6）h,术中平均出血量1980（700—3600）ml。术后后凸角由手术前平均54．5°矫正到16．5°,矫正角度38°。随访6～72个月,其间畸形矫正无明显丢失,除2例出现下肢麻痹外,其余均未出现神经系统并发症。结论L1椎体楔形截骨椎弓根螺钉内固定术矫治脊柱后凸畸形固定可靠,矫形效果满意。     

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.