寰椎椎弓根进钉通道的数字解剖学研究

目的:探讨寰椎椎弓根进钉通道在矢状面角(SSA)为0°时不同水平面角(TSA)方向投影的变化规律。方法:将20例健康成年志愿者(男12例,女8例;年龄24~68岁,平均45岁)的寰椎CT连续断层扫描数据导入Mimics 10.01软件,三维重建寰椎数字解剖模型,将重建的结果以.stl格式保存,再将寰椎数字模型导入UG Imageware 12.0,建立寰椎椎弓根进钉通道数字化分析方法,确定三维参考平面,分析在SSA为0°时左右椎弓根TSA分别从0°～30°,均匀间隔5°,观察280个寰椎椎弓根进钉通道的长度和内切圆半径的变化规律。结果:280个寰椎椎弓根进钉通道的长度为20.54～33.21mm,其中11个通道长度小于最短椎弓根螺钉长度(22mm);TSA为0°进钉时左右通道长度均最大,左右侧比较无显著性差异(P0.05),5°～30°进钉时同一进钉角度左右侧比较有显著性差异(P0.05);同侧不同进钉角度比较无显著性差异(P0.05)。280个寰椎椎弓根螺钉通道的内切圆半径为1.38～2.51mm,其中有42个内切圆半径小于最小椎弓根螺钉半径(1.75mm);同一进钉角度右侧内切圆半径与左侧比较及同侧不同进钉角度比较均无显著性差异(P0.05)。结论:不同个体甚至同一个体的左右两侧椎弓根形态之间有较大差异。部分寰椎椎弓根进钉通道长度和内切圆半径小于椎弓根螺钉最小长度和最小半径,椎弓根进钉通道内切圆半径小于最小椎弓根螺钉半径时置钉会穿破椎弓根的皮质骨,不适合采用经寰椎椎弓根螺钉内固定技术。术前用数字化技术测量寰椎椎弓根进钉通道可以实现个体化置钉。     

计算机3D建模模拟个体化枢椎椎弓根钉最佳进钉方式的应用

[目的]利用3D建模技术观察枢椎椎弓根通道,置钉安全区,测量最佳置钉方案。制订标准、简化的枢椎椎弓根螺钉进钉术前设计方案。[方法]从本院PACS系统14例健康成人(男7例,女7例;年龄30⁶8岁,平均45岁)的枢椎CT连续断层扫描数据导入Mimics 10.01软件,三维重建后利用.dwg文件导入3dmax2009。确定三维参照坐标和进钉点,用3 dmax中参考建模命令建立17×17×2间距2.5°TSA(水平面角)068岁,平均45岁)的枢椎CT连续断层扫描数据导入Mimics 10.01软件,三维重建后利用.dwg文件导入3dmax2009。确定三维参照坐标和进钉点,用3 dmax中参考建模命令建立17×17×2间距2.5°TSA(水平面角)0⁴0°,SSA(矢状面角)040°,SSA(矢状面角)0⁴0°共578元素模拟椎弓根螺钉阵列模型,通过透视图观察直径为3.5 mm,长度为24 mm模拟螺钉在椎弓根通道中情况,从而确定安全区,最后测量最佳置钉方案螺钉角度。[结果]14例受试者矩阵研究元素总数目为17×17×2×14共8 092个元素单位。其中395个元素符合进钉要求。螺钉最远距离进行比较,差异无统计学意义(P>0.05)。[结论]利用数字3D建模技术能建立标准、简化、精确的术前设计方案。     

采用椎弓根螺钉内固定治疗寰枢椎骨折脱位

[目的]探讨寰枢椎椎弓根螺钉技术治疗创伤性寰枢椎不稳的临床效果。[方法]2009年9月~2017年3月,对6例创伤性寰枢椎不稳患者采用颈椎后路寰枢椎椎弓根螺钉固定技术治疗。术前均常规行颅骨牵引,椎弓根进钉点位于寰椎椎弓两侧距后结节20 mm、后弓下缘2 mm,内倾5°~10°、头倾10°~15°,置入直径3.5 mm、长22~26 mm螺钉。枢椎螺钉的进钉点位于侧块内上象限,内倾约25°,头倾约25°置入直径3.5 mm、长24~28 mm螺钉。[结果]术中无血管及神经损伤。术后随访6~36个月,患者临床症状得到明显改善。术后检查显示螺钉位置良好,无内置物松动、断裂。术后12个月JOA评分为11.00~17.00分。[结论]寰枢椎椎弓根螺钉固定治疗创伤性寰枢椎不稳疗效满意。     

前路枢椎椎弓根螺钉固定通道的CT测量及临床应用

目的:探讨CT扫描测量指导前路枢椎椎弓根螺钉置人的临床应用价值.方法:对20具干燥枢椎标本行椎弓根螺钉置入,然后应用CT测量进针的角度、钉道长度以确定最佳进钉点,并根据测量数据和术前影像学检查对10例难复性寰枢椎脱位患者行前路寰枢椎复位椎弓根螺钉固定植骨融合术,观察寰枢椎复位及螺钉位置情况.结果:枢椎椎弓根的平均长度为25mm,进针点距离枢椎正中线6.6mm,安全进钉的角度向外倾斜21°±2°,下倾10°±2°.10例患者寰枢椎均完全复位,枢椎椎弓根螺钉均位于椎弓根钉道内.结论:前路寰枢椎椎弓根螺钉固定有较高的安全性,术前行CT扫描对于前路寰枢椎内固定手术有重要的指导意义.     

枢椎椎板螺钉联合寰椎椎弓根螺钉固定治疗寰枢椎脱位

目的 评价枢椎椎板螺钉联合寰椎椎弓根螺钉固定融合治疗寰枢椎脱位的临床可行性.方法 对5例枢椎椎弓根细小的寰枢椎脱位患者,在气管插管全身麻醉下施行了枢椎椎板螺钉联合寰椎椎弓根螺钉固定术.枢椎椎板螺钉的进钉点位于棘突两侧椎板交界处,交叉置人对侧椎板内;寰椎椎弓根螺钉的进钉点位于枢椎侧块中线上,距寰椎后弓上缘最少3 mm,内斜10°,上斜5°.螺钉直径3.5 mm,枢椎椎板螺钉长26～32 mm,寰椎椎弓根螺钉长28～32 mm,结合自体髂骨植骨.结果 患者获得随访3～18个月,平均7.5个月.未发生椎动脉、脊髓损伤,术后临床症状得到不同程度的改善,X线、CT复查螺钉位置良好,无松动、断钉,植骨3个月后均达到满意融合.结论 枢椎椎板螺钉联合寰椎椎弓根螺钉固定治疗寰枢椎脱位效果满意,是又一可供选择的寰枢椎后路固定术式.     

后路寰椎侧块螺钉结合枢椎椎弓根螺钉固定治疗上颈椎不稳

目的：总结应用寰椎侧块螺钉与枢椎椎弓根螺钉技术固定融合治疗寰枢椎不稳的效果，探讨寰枢椎不稳的治疗方法。方法：采用寰椎侧块螺钉与枢椎椎弓根螺钉技术对15例寰枢椎不稳的患者进行了固定术，同时行自体髂骨融合。分别应用Vertex 7例，Axis 3例，和cervifix 5例，齿状突陈旧性骨折5例，新鲜Ⅱc型齿状突骨折6例，先天性游离齿状突4例。寰椎侧块螺钉进钉点选择在寰椎后结节中点旁开18mm～20mm，与后弓下缘以上2mm的交点，钉道方向在冠状面垂直，矢状面上螺钉头端向头侧倾斜约5°.枢椎进钉点为枢椎下关节突根部中点，钉道与矢状面夹角约15°，横断面夹角约30°。螺钉直径3．5mm，寰椎侧块螺钉长度28mm～32mm，枢椎椎弓根螺钉长度为22mm～26mm。结果：所有患者均未发生脊髓损伤和椎动脉损伤。随访10～25个月，平均14个月。术前JOA评分5．1～10．9分，平均7．6分。术后JOA评分13．2～16．8分，平均14．8分，改善率87．5％。植骨块全部融合，无内固定断裂、松动。结论：后路寰椎侧块螺钉与枢椎椎弓根螺钉技术稳定性良好，具有三维固定的优点，值得推广。     

寰枢椎椎弓根影像学测量及临床应用

[目的]探讨利用影像学资料,测量寰枢椎椎弓根的数据,提高寰枢椎椎弓根置钉的成功率. [方法]对寰枢椎CB、DR X线片、MBI及64排CT片,通过图像储存传输系统,测量寰椎椎弓根进行进钉点、进钉角度的测量. [结果]寰椎椎弓根进钉点:左侧(19.93±1.32)mm,右侧(19.16±1.30)mm;寰椎椎弓根向内侧进钉角度:左侧23.72°±2.09°,右侧23.35°±1.91°;寰椎向头侧进钉角度9°±1.2°.枢椎椎弓根进钉点:左侧(13.14±0.82)舢,右侧(13.85±0.79)mm;枢椎椎弓根向内侧进钉角度:左侧24.52°±1.26°,右侧20.42°±1.42°;枢椎向头侧进钉角度25°±3°.对48例患者行寰枢椎椎弓根经椎弓根内固定手术.其中男35例,女13例.年龄22～61岁,平均43.60岁.Ⅱ型陈旧性齿状突骨折22例,齿状突不连12例,横韧带损伤14例.所有患者X线片示寰椎完全复位,枢椎齿状突骨折处对位良好.平均10.6个月,均获得骨性融合.按JOA评分标准,优31例,良14例,可2例,差1例,优良率93.75%. [结论]利用影像学资料测量,对寰枢椎椎弓根内固定手术的实际操作有良好的指导意义.     

枢椎椎弓峡部引导下寰椎椎弓根置钉的CT测量及其应用

目的:探讨在枢椎椎弓峡部引导下实施寰椎椎弓根螺钉置钉的可行性及安全性。方法:对48例成人寰枢椎行三维CT重建,取枢椎椎弓峡部内上缘与寰椎的横断面图像。测量椎管正中线至寰椎椎弓根内壁、外壁及枢椎椎弓峡部内壁、外壁的距离,分别为L1、D1、L2、D2;0°内倾角置钉时,以枢椎椎弓峡部内上壁为解剖标志,确立最内侧进钉点A和最外侧进钉点B,减去螺钉半径1.75mm,A、B点至枢椎椎弓峡部内上壁的距离分别为(L1-L2+1.75mm)、(D1-L2-1.75mm),寰椎后弓上置钉时螺钉允许的最大内倾角与最大外倾角大致相等时的点为最佳进钉点(M点),记录M点至枢椎椎弓峡部内上壁水平间距。自2004年3月～2009年3月对29例患者采用以枢椎椎弓峡部为标志实施后路寰枢椎椎弓根螺钉内固定手术,其中陈旧性齿状突骨折24例,横韧带损伤并寰椎前脱位5例。观察手术过程中与寰椎椎弓根螺钉置钉相关的并发症,术后三维CT重建观察螺钉的位置。结果:0°内倾角置钉时,CT测量最内侧进钉点A、最外侧进钉点B、最佳进钉点M至枢椎椎弓根峡部内上壁的水平间距分别为4.22±0.54mm、8.66±0.73mm、5.79±0.63mm。临床共置入寰椎椎弓根螺钉58枚,术中枢椎椎弓峡部内上壁均得到良好显露,未出现椎动脉、静脉丛损伤出血及脊髓、C2神经根损伤等并发症。术后三维CT复查显示所有寰椎椎弓根螺钉均未误入椎管或椎动脉孔,测量寰椎椎弓根螺钉进钉点与枢椎椎弓峡部内上壁水平间距为5.45±0.82mm,与术前M点测量值相比较无显著性差异。结论:在纠正寰椎旋转移位后,以枢椎椎弓峡部内上壁作为解剖参照,寰椎椎弓根存在一定的置钉安全区间,利用该解剖标志行寰椎椎弓根置钉是安全可行的。     

后路寰枢椎椎弓根钉内固定及融合术治疗上颈椎不稳11例

目的总结采用寰枢椎椎弓根钉内固定及植骨融合术治疗上颈椎不稳的疗效。方法对11例上颈椎不稳患者术前常规行颅骨牵引复位。术中寰枢椎椎弓根的进钉点选择在寰椎后结节中点旁开18～20 mm、后弓上缘下4 mm交点处,矢状面上螺钉向头侧倾斜约5°,与矢状面夹角10°;枢椎进钉点为枢椎关节突根部中点,钉道与矢状面夹角为20～25°,与横断面夹角30～35°。椎弓根钉直径3.5 mm,寰椎、枢椎椎弓根钉长22～28 mm。结果随访5～34个月,11例均植骨融合,内固定无松动断裂。术后JOA评分:优7例,良2例,可2例。结论采用寰枢椎多轴椎弓根钉棒系统内固定及植骨融合术治疗上颈椎不稳,具有固定牢固、固定节段短和三维固定的优点。     

后路寰椎侧块螺钉结合枢椎椎弓根螺钉固定治疗寰枢椎不稳

目的探讨应用寰椎侧块螺钉与枢椎椎弓根螺钉固定融合治疗寰枢椎不稳的疗效。方法2002年2月至2004年3月,采用寰椎侧块螺钉结合枢椎椎弓根螺钉技术治疗寰枢椎不稳15例,男9例,女6例;年龄15～57岁,平均39.5岁;齿突陈旧性骨折5例,先天性游离齿突4例,新鲜齿突骨折6例(AdersonⅡC型)。所有患者均伴有寰枢椎半脱位或不稳,表现为不同程度的颈枕区疼痛,活动受限。术前JOA评分5.1￣10.9分,平均7.6分。术前行颅骨牵引。寰椎侧块螺钉进钉点选择在寰椎后结节中点旁18￣20mm与后弓下缘以上2mm的交点处,钉道与冠状面垂直,矢状面上螺钉头端向头侧倾斜约5°。枢椎椎弓根螺钉进钉点为枢椎下关节突根部中点,钉道与矢状面夹角约15°,与横断面夹角约30°。螺钉直径3.5mm,寰椎侧块螺钉长28～32mm,枢椎椎弓根螺钉长22～26mm。应用Vertex7例,Axis3例,Cervifix5例。结果15例患者共置入寰椎侧块螺钉和枢椎椎弓根螺钉各30枚。术后无一例患者发生脊髓和椎动脉损伤。所有患者均获随访,随访时间10～25个月,平均14个月。术后6个月JOA评分13.2～16.8分,平均14.8分,改善率为87.5%。骨折的齿突均骨性愈合,植骨块全部融合,无内固定断裂、松动。结论后路寰椎侧块螺钉结合枢椎椎弓根螺钉固定具有稳定的三维固定效果,可用于治疗寰枢椎不稳。     

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.     

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.     

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.     

Systemic analgesia adapted to the children's condition

A concept of balanced analgesia using nonsteroidal anti-inflammatory drugs (NSAIDs), paracetamol (acetaminophen), opioids, and corticosteroids can also be used in patients with pre-existing illnesses. NSAIDs are the most effective treatment for acute pain of moderate intensity in children; however, these drugs should be avoided in patients at increased risk for serious side effects, e.g. patients with renal impairment, bleeding tendency, or extreme prematurity. NSAIDs can be given with minimal risks to the younger child with mild to moderate asthma, and, in these patients, the use of steroids can be encouraged; in addition to their antiemetic and analgesic action, a beneficial effect on asthma symptoms can be expected. In the non-intubated child with cerebral trauma, exaggerated sedation caused by opioids and increased bleeding tendency caused by NSAIDs must be avoided. In neonates and small infants, the oral administration of sucrose or glucose is helpful to minimize pain reaction during short uncomfortable interventions.