经口咽前路寰枢椎复位钢板的生物力学评价

目的 对经口咽前路寰枢椎复位钢板(Transoralpharyngeal Atlantoaxial Reduction Plate，TARP)。进行生物力学评价。方法 6例寰枢椎新鲜标本，在脊柱三维运动试验机上将四种常用的寰枢前后路融合术与我们自行设计的经口咽前路寰枢椎复位钢板进行对比，分7组：①对照组(完整标本)；②损伤组；③前路寰枢椎复位钢板组；④后路Brooks钢丝组；⑤Magerl Brooks组；⑥Magerl组；⑦前路经枢椎体寰椎侧块螺钉组(ATS)。分别测量其三维运动范围(ROM)。结果 TARP和Magerl Brooks在各个方向上均无显著性差异，ROM值略大于后者，除在侧屈时和旋转与Magerl无显著差异外，二者抗屈伸、侧屈和旋转均强于其它内固定方法。Magerl除在侧屈和旋转范围与Brooks、前路经枢椎体寰椎侧块螺钉的旋转范围无显著差异外，与Brooks和前路经枢椎体寰椎侧块螺钉在其它运动有显著差异，ROM值小于Brooks和前路经枢椎体寰椎侧块螺钉。Brooks和前路经枢椎体寰椎侧块螺钉在各向上均无显著差异。结论 TARP与Magerl Brooks较其它三种临床上常用的前后路寰枢融合手术固定更牢靠，TARP具有良好的生物力学性能。联合后路Magerl Brooks较单用后路Magerl更牢固。前路经枢椎体寰椎侧块螺钉固定与Brooks钢丝效果相当。     

经口咽前路寰枢椎复位钢板内固定的生物力学研究

目的 研究经口咽前路寰枢椎复位钢板(TARP)的三维运动范围和螺钉拔出力的生物力学. 方法 12例C0～C3新鲜标本,6例用于三维运动测试,分七组:①完整标本(对照)组,②损伤组(去除C1前弓、C2齿突,破坏关节囊和横韧带等),③TARP组,④后路Brooks钢丝组,⑤Magerl经关节螺钉组,⑥Magerl+Brooks组,⑦前路经枢椎体寰椎侧块螺钉组,分别测量其三维运动范围(ROM).另6例(双侧,n=12)分解为单个椎体后用于螺钉拔出力测试,分三组:①寰椎组,②枢椎组,③C,(对照)组,测定最大拔出力、钉道长度和屈服长度.结果 TARP组和Magerl+Brooks组在各个方向上差异均无统计学意义(P>0.05),前者的ROM值略大于后者,二者抗屈伸、侧屈和旋转均强于其他三种内固定方法(P<0.05).寰椎与枢椎、寰椎与C3的最大拔出力之间差异均有统计学意义(P<0.05),枢椎和c3椎体最大拔出力之间差异无统计学意义(P>0.05)[最大拔出力分别为C1=(491.58 4±67.92)N,C2=(396.73±60.99)N,C3=(385.53±96.77)N].寰椎与枢椎、寰椎与C3椎体的钉道长度之间差异均有统计学意义(均为P<0.05),枢椎和C3椎体钉道长度之间差异无统计学意义(P>0.05).三组的屈服长度之间差异.无统计学意义(P>0.05).C1～C3的螺钉最大拔出力与钉道长度和屈服长度均呈显著正相关(P<0.05,r分别为0.810和0.652),但与钉道长度的相关性更高(P<0.05). 结论 TARP与目前临床应用的后路Magerl+Brooks术式等效,较其他三种固定方式(前路经枢椎体寰椎侧块螺钉、后路Magerl经关节螺钉和后路Brooks钢丝固定)具有更坚强的固定作用.TARP的寰椎和枢椎固定螺钉固定牢靠,钉道长度即进钉深度是影响螺钉抗拔出力的主要因素,屈服长度是影响螺钉拔出力的次要因素.     

经口咽前路寰枢椎复位钢板治疗难复性寰枢椎脱位

目的 设计经口咽前路寰枢椎复位钢板系统(transoralpharyngeal atlantoaxial reduction plate,TARP)，评价其生物力学性能，观察临床应用效果。方法 研制设计一种新型的经口咽前路寰枢椎复位钢板系统，该系统包括-蝶形钛合金锯板、自锁螺钉和寰枢椎复位器等配套安装器械。将此系统在12具C0-C3新鲜标本上分别进行了三维运动测试(n=6)和拔出力实验(n=12)，比较其生物力学性能，并临床治疗难复性寰枢椎脱位患者5例。结果 TARP系统设计有巧妙的即时复位机制。TARP的生物力学性能与现行的寰枢椎融合Magerl Brooks固定等效，较其它三种方法(前路经枢椎体寰椎侧块螺钉、后路Magerl经关节螺钉和后路Brooks钢丝)具有更坚强的固定作用，TARP的寰椎和枢椎固定螺钉固定牢靠，具有良好的抗拔出性能。经难复性寰枢椎脱位的临床应用，TARP能达即时复位作用，手术操作可行，效果显著。结论 TARP设计新颖独到，具有良好的生物力学性能，手术能达即时复位，固定效果好，为临床提供了—个崭新的治疗方法。     

经口咽前路寰枢椎蝶形钢板系统的设计及生物力学评估

目的　设计经口咽前路寰枢椎蝶形钢板内固定系统 ,评价其生物力学性能。方法　设计研制各种型号经口咽前路寰枢椎蝶形钢板、自锁螺钉和复位器等配套器械。选 12具新鲜成年颈椎标本 ,分别进行三维运动范围实验和螺钉拔出力实验。与其他内固定方法作比较分析。结果三维运动范围 ,TARP、Brooks、Magerl、前路经枢椎体寰椎侧块螺钉和Magerl Brooks组的屈伸方向的运动范围分别为平均 4.0、6.2、5 .1、6.6和 3 .7度 ;在侧屈方向的活动范围分别为平均 2 .3、3 .6、2 .7、4.2和 1.8度 ;在旋转活动范围分别为平均 7.4、8.9、8.6、10 .7和 6.0度。结果显示该蝶形钢板固定和Magerl Brooks固定在各个方向上差异均无显著性 (P >0 .0 5 )。其抗屈伸、侧屈和旋转均强于其他 3种内固定方法。寰椎、枢椎和第 3颈椎组的螺钉固定的最大拔出力分别为平均491.5 8、3 96.73和 3 85 .5 3N。结果显示寰椎螺钉的最大拔出力显著高于枢椎和C3 椎体固定螺钉 ,枢椎螺钉与C2 螺钉等效。结论　经口咽前路蝶形钢板系统设计新颖、独特 ,具有良好的生物力学性能。为临床应用提供了生物力学依据。     

前路经枢椎体至寰椎侧块螺钉内固定三维稳定性的实验研究

目的：评价前路经枢椎体至寰椎侧块螺钉内固定三维稳定性。方法：16具成人标本（C0–C3）,对每一标本分别测定完整状态（第1组）、齿状突Ⅱ型骨折（第2组）、后路经关节螺钉内固定术（Magerl技术）（第3组）、前路经枢椎体至寰椎侧块螺钉内固定（第4组）4种状态下的三维运动范围,并进行统计学分析。结果：1组与其他3组、2组与其他3组比较差异有统计学意义（P〈0.001）。前路经枢椎体至寰椎侧块螺钉内固定与后路Magerl螺钉内固定均能显著减少寰枢关节各方向运动范围,两种固定方法差异无统计学意义（P〉0.05）。结论：前路经枢椎体至寰椎侧块螺钉内固定的三维稳定性与后路Magerl螺钉内固定术相当,为寰枢椎不稳定及脱位患者的治疗提供了一种可靠的手术选择。     

寰枢椎前路复位钢板系统的研制及其生物力学

目的研制一种经口咽前路寰枢椎复位钢板内固定系统,评价其生物力学性能。方法研制各种型号经口咽前路寰枢椎复位钢板和复位器等配套器械。选12具新鲜成年颈椎标本,分别进行三维运动范围实验和螺钉拔出力实验。与其它内固定方法作比较分析。结果生物力学测试表明,三维运动范围,该钢板固定和Magerl Brooks固定在各个方向上均无显著差异(P>0.05)。其抗屈伸、侧屈和旋转均强于其它三种内固定方法。寰椎螺钉的最大拔出力显著高于枢椎和C3椎体固定螺钉,枢椎螺钉与C2螺钉等效。结论寰枢椎前路复位钢板系统设计新颖,具有良好的生物力学性能。能满足临床内固定需要。     

经口咽前路寰枢椎复位钢板固定螺钉拔出强度的实验研究

目的:对经口咽前路寰枢椎复位钢板(transoralpharyngealatlantoaxialreductionplate,TARP)螺钉进行固定螺钉拔出力实验,探讨TARP螺钉固定的可行性。方法:6例C1~C3椎体新鲜标本,左右双侧均行螺钉固定,寰椎螺钉固定于侧块,枢椎和C3椎体螺钉固定于椎体。在生物力学实验机上通过传感器测定TARP寰椎和枢椎固定螺钉的最大拔出力、钉道长度,并将结果同C3椎体螺钉固定进行比较。结果:寰椎与枢椎、寰椎与C3椎体的固定螺钉的最大拔出力之间均有显著性差异,枢椎和C3椎体最大拔出力之间无显著性差异。寰椎与枢椎、寰椎与C3椎体的钉道长度之间均有显著性差异,枢椎和C3椎体钉道长度之间无显著性差异。C1～C3的最大拔出力与钉道长度呈显著正相关(r=0.810)。结论:TARP螺钉固定是比较安全的,固定时一般采用钻孔后丝攻攻破寰椎、枢椎和C3椎体前表面较硬的骨质后用单皮质螺钉固定。钉道长度(即进钉深度)是影响拔出力的重要因素。     

经口咽前路寰枢椎复位钢板系统的研制与初步临床应用

目的 研制经口咽前路寰枢椎复位钢板系统(TARP),评价其生物力学性能,并进行初步的临床应用观察。方法研制设计一种新型的经口咽前路寰枢椎复位钢板系统,该系统包括蝶形钛合金钢板、自锁螺钉和寰枢椎复位器等配套安装器械。将此系统在12具枕骨～C3新鲜标本卜分别进行了三维运动测试(n=6)和拔出力实验(n=12),比较其生物力学性能,并初步临床应用3例。结果TARP系统设计有巧妙的即时复位饥制。 TARP、Brooks钢丝、Magerl经关节螺钉、前路螺钉以及Brooks钢丝 Magerl经关节螺钉等5组在屈伸方向的平均活动范同分别为4．0、6．2、5．1、6．6、3．7度;在侧屈方向的平均活动范围分别为2．3、3．6、2．7、4．2、1．8度;平均旋转活动范围分别为7．4、8．9、8．6、10．7、6．0度。结果显示TARP的生物力学性能与Brooks钢丝 Magerl经关节螺钉固定等效,较其他3种方法具有更坚强的固定作用。临床应用术后随访平均8．3个月,3例寰椎完全复位,伤口愈合良好,无感染,四肢麻痹消失,肌力恢复,病理反射消失?钢板螺钉未松动。结论TARP设计新颖独到,具有良好的生物力学性能,手术操作简便易行,能达到即时复位,固定效果好,具有良好的应用前景。     

骨科——脊柱

经口咽前路寰枢椎复位钢板内固定的外科解剖学研究；用Gallie术式治疗寰枢关节不稳定的临床问题研究；枢椎椎体骨折;颈椎前路手术并发食道瘘的诊断与治疗；颈部旋转与侧屈活动对椎动脉血供的影响；颈脊柱姿势及预负荷史对压缩强度影响的生物力学研究；颈椎前路带锁钢板内固定治疗颈椎骨折并四肢瘫痪；前路螺钉固定治疗齿状突骨折脱位合并颈髓不全损伤27例；经寰椎后弓侧块螺钉固定治疗上颈椎损伤；短节段内固定、ACPC椎体成形治疗胸腰椎骨折的围手术期观察；颈椎疾病前后路手术的选择与并发症的防治(附512例报告)；     

三种后路寰枢椎融合术的离体生物力学研究

目的 通过离体生物力学研究方法,比较3种后路寰枢椎融合技术的力学稳定性.方法 将8具新鲜尸体的颈椎标本(C1～4)置于1.5 Nm载荷下,测量C1、2关节的三维运动范围(ROM).每具标本依双侧经寰枢关节间隙螺钉结合Gallie内固定术、双侧经寰枢关节间隙螺钉结合寰椎椎板钩内固定术、双侧寰椎侧块螺钉结合枢椎椎弓根螺钉内固定术的顺序实施固定,每次固定后测量三维运动范围.结果 包含经寰枢关节间隙螺钉的内固定组在旋转和侧屈方向上具有最小的ROM角度,其中新型的双侧经寰枢关节间隙螺钉结合寰椎椎板钩内固定组在前屈后伸运动方向上也具有最小ROM角度.寰椎侧块螺钉结合枢椎椎弓根螺钉内固定组在旋转方向上ROM角度显著大于单独经寰枢关节螺钉内固定组,但在侧屈和前屈后伸方向上ROM角度近似于经寰枢关节间隙螺钉,差异无统计学意义.结论 双侧经寰枢关节间隙螺钉结合寰椎椎板钩内固定术具有最强的生物力学稳定性;双侧寰椎侧块螺钉结合枢椎椎弓根螺钉内固定术与双侧经寰枢关节间隙螺钉结合寰椎椎板钩内固定技术比较,具有相似的力学稳定性.     

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.     

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.     

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.