通用型脊柱内固定系统椎弓根螺钉的生物力学测试

目的测试自行设计的通用型脊柱内固定系统(generalspinesystem,GSS)椎弓根螺钉以及SOCON和CCD螺钉置入正常成人椎体标本的最大轴向拔出力及最大旋入力矩,评价GSS螺钉对椎弓根的锚固作用。方法将27个正常成人腰椎椎体标本随机分为3组,每组9个椎体(18侧椎弓根),分别置入GSS、SOCON和CCD椎弓根螺钉,行螺钉拔出试验,测试并记录螺钉的最大旋入力矩和最大轴向拔出力。结果三组螺钉的最大旋入力矩分别为(1.83±0.27)Nm、(2.09±0.51)Nm和(1.66±0.34)Nm,最大轴向拔出力分别为(1131.0±255.4)N、(1034.0±262.3)N和(886.1±152.9)N。GSS螺钉最大轴向拔出力最大,且与CCD螺钉相比差异有非常显著性意义(P<0.01)。结论GSS螺钉具有很强的椎弓根锚固作用。     

通用型脊柱内固定系统椎弓根螺钉翻修作用的生物力学研究

目的测试自行设计的通用型脊柱内固定系统(generalspinesystem,GSS)椎弓根螺钉以及SOCON、TSRH和Diapason螺钉置入椎体的拔出力及旋入力矩,评价GSS螺钉的翻修作用。方法将36个正常成人腰椎椎体标本随机分为三组,每组12个椎体(24侧椎弓根)。各组标本每个椎体的每侧椎弓根均先拧入CCD螺钉(直径6.0mm,长45mm),行螺钉拔出试验,测试并记录螺钉的最大旋入力矩和最大轴向拔出力。然后各组标本每个椎体均随机选择一侧椎弓根经原钉道拧入GSS螺钉(直径6.5mm,长45mm);第一组另一侧拧入SOCON螺钉(直径7.0mm,长45mm),第二组另一侧拧入TSRH螺钉(直径7.0mm,长45mm),第三组另一侧拧入Diapason螺钉(直径6.7mm,长45mm)。分别测试螺钉最大旋入力矩及最大轴向拔出力。结果第一组GSS螺钉最大轴向拔出力为CCD螺钉的114%,SOCON螺钉为CCD螺钉的108%;GSS螺钉最大轴向拔出力大于SOCON螺钉,差异无显著性(P>0.05);GSS螺钉最大旋入力矩小于SOCON螺钉,差异无显著性(P>0.05)。第二组GSS螺钉最大轴向拔出力为CCD螺钉的127%,TSRH螺钉为CCD螺钉的64%;GSS螺钉最大轴向拔出力大于TSRH螺钉,差异有显著性(P<0.01);GSS螺钉最大旋入力矩大于TSRH螺钉,差异有显著性(P<0.01)。第三组GSS螺钉最大轴向拔出力为CCD螺钉的122%,Diapason螺钉为CCD螺钉的8     

椎弓根螺钉不同翻修方法的生物力学研究

目的：研究增加螺钉直径和长度、钉孔内植骨以及聚四氟乙烯膨胀螺栓强化这四种椎弓根螺钉翻修方法所各自产生的最大轴向拔出力和最大置入扭矩变化，以确定椎弓根螺钉的最佳翻修方法。方法：将6具成人T10～L5椎体标本，分为：(1)增加椎弓根螺钉直径组，(2)延长椎弓根螺钉长度组，(3)增加直径 延长长度组，(4)植骨组，(5)聚四氟乙烯膨胀螺栓组，(6)退出后再置组。将最初置入的直径5．0mm、长40mm螺钉时所测得的最大扭矩和最大轴向拔出力作为对照组数据；记录翻修螺钉最大扭矩和最大轴向拔出力与相应对照组数据之间的变化量，各组之间结果行统计学分析。结果：在增加螺钉直径和(或)长度的方法中，当螺钉直径增加2mm且长度增加10mm时，扭矩和最大轴向拔出力的增加最明显，分别为37．06％和18．22％；螺钉直径增加2mm，扭矩增加20．15％，最大轴向拔出力增加19．99％；螺钉直径增加1mm、长度增加5mm，扭矩增加19．23％，最大轴向拔出力增加10．07％；螺钉长度单纯增加5mm与10m，扭矩分别下降32．80％和14．02％，最大轴向拔出力分别下降27.36％和增加43．25％；钉孔内植骨后再置入螺钉，扭矩和轴向拔出力分别下降了14．99％和29．34％；聚四氟乙烯膨胀螺栓强化后再置入螺钉，扭矩显著增加，而轴向拔出力下降了37．40％；螺钉退出后再置，扭矩下降了34．22％。结论：螺钉直径增加2mm对椎弓根螺钉翻修最有效，其次为螺钉直径增加1mm、长度增加5mm。钉孔内植骨的方法不可取。聚四氟乙烯膨胀螺栓强化的翻修方法需进一步研究。     

SSA角度与椎弓根螺钉拔持力的相关性研究

目的 观察椎弓根螺钉不同矢状成角(SSA)置入后单个椎体的拔钉生物力学研究,为临床置钉提供理论依据.方法 采用6月龄猪新鲜L1共12个椎体标本,将24侧椎弓根分3组,按矢状成成角0°组、-20°组、10°组置入椎弓根螺钉,测出最大轴向拔出力.结果 -20°组椎弓根螺钉拔出力及拔出能量最大,0°组螺钉拔出力及拔出量最小,10°组界于二者之间,3组之间最大拔出力及拔出能量两两比较P＜0.05,提示各组之间差异均有统计学意义.结论 矢状面成角置钉对螺钉的把持力大于0°角钉.随置钉角度的增加把持力也逐渐增大.     

L_5、S_1前路经椎弓根螺钉固定的生物力学研究

目的探讨L5、S1前路经椎弓根螺钉固定生物力学特性。方法 7具完整新鲜尸体腰骶段(L5、S1)脊柱标本,双能X线骨密度测量后排除严重骨质疏松者,分解成两个独立完整椎体(L5、S1)。每个椎体植入前路椎弓根螺钉(ATPS)、后路椎弓根螺钉(PTPS)和椎体螺钉(TVS),对置入的3种螺钉进行旋入扭矩和抗拔出力试验,比较3种螺钉固定方式的最大扭矩和轴向拔出力。结果 L5、S1的平均最大扭矩:ATPS为(1.25±0.01)N·m,PTPS为(1.35±0.01)N·m,TVS为(0.40±0.01)N·m;ATPS和PTPS之间差异无统计学意义(P0.05),ATPS、PTPS与TVS间差异有统计学意义(P0.05)。L5、S1的平均最大拔出力:ATPS为(1 630±65)N,PTPS为(1 730±60)N,TVS为(680±50)N;ATPS和PTPS之间差异无统计学意义(P0.05),ATPS、PTPS与TVS之间差异有统计学意义(P0.05)。螺钉旋入最大扭矩与螺钉拔出力呈正相关性。结论 L5、S1ATPS和L5、S1PTPS两种固定的平均最大扭矩和平均最大拔出强度差异并不明显,但均大于TVS固定。L5、S1ATPS固定有较好的生物力学优势。     

枢椎棘突螺钉与椎弓根螺钉固定的生物力学拔出力比较

目的 比较枢椎棘突螺钉和椎弓根螺钉的生物力学拔出力强度.方法 取8具新鲜尸体枢椎标本(C2).于椎体两侧随机进行枢椎棘突螺钉和椎弓根螺钉固定,置入直径为4.0 mm的皮质骨螺钉.枢椎棘突螺钉进钉点选择为棘突的基底部、棘突及椎板的交界处,进钉角度为水平置钉,螺钉由对侧棘突基底部穿出,形成双层皮质固定;枢椎椎弓根螺钉在直视椎弓根下置钉.置钉后行拔出强度实验,比较2种螺钉的最大轴向拔出力强度.结果 枢椎棘突螺钉的平均拔出力强度为(387.56±137.73)N,稍小于枢椎椎弓根螺钉的平均拔出强度(465.25±214.32)N,差异无统计学意义(t=-0.862,P =0.403);枢椎棘突螺钉的平均钉道长度为(21.42±1.14) mm,稍短于枢椎椎弓根螺钉的(23.16±1.01) mm,差异有统计学意义(t=4.368,P ＜0.05). 结论 枢椎棘突螺钉具有椎弓根螺钉相近的生物力学拔出力强度,枢椎棘突螺钉在生物力学上具有应用可行性.     

腰椎不同深度置入椎弓根螺钉对把持力的影响

目的：观察椎弓根螺钉在相同水平角度（TSA 角为0°）、相同矢状角度（SSA 角为0°）不同深度时置入单个椎体对把持力的影响,为临床置钉提供理论依据。方法采用6个月龄猪 L2新鲜标本共16个椎体,将32侧椎弓根分4组,按不同深度分70％组、75％组、80％组、85％组分别置入椎弓根螺钉,自动记录仪记录下螺钉载荷-位移的变化曲线,测出最大轴向拔出力及最大拔出能量。结果80％组椎弓根螺钉最大拔出力及最大拔出能量明显大于70％组（P ＜0．05）,75％组与85％组椎弓根螺钉的最大拔出力及最大拔出能量与70％组比较差异无统计学意义（P ＞0．05）。结论不同深度置钉对椎弓根螺钉的把持力随置钉深度的增加而逐渐增大。     

膨胀式脊柱内固定系统椎弓根螺钉翻修作用的生物力学研究

目的：评价自行设计的膨胀式脊柱同定系统（expansive spinal fixation system，ESFS）的椎弓根螺钉对椎弓根螺钉固定失败后的翻修作用。方法：将30个深低温冰冻的正常成人腰椎体标本随机分为A、B、C三组．每组10个椎体（20侧椎弓根）。各组标本每个椎体的两侧椎弓根均先拧入直径6．0mm、长45mm的CD-Ⅱ螺钉．行螺钉拔出试验，记录螺钉的最大旋入力矩和最大轴向拔出力。然后将CD-Ⅱ螺钉拔出，各组标本每一椎体随机经一侧椎弓根原钉道拧入直径7．0mm、长45mm的ESFS螺钉；A组另一侧椎弓根拧入直径7．0mm、长45mm的CD-Ⅱ螺钉，B组另一侧拧入直径7．0mm、长45mm的TSRH螺钉．C组另一侧拧入直径7．0mm、长45mm的GSS螺钉。分别测试螺钉最大旋入力矩和最大轴向拔出力。结果：A、B、C三组的ESFS螺钉最大轴向拔出力分别为6mm CD-Ⅱ螺钉的113％、110％和112％，而直径7．0mm、长45mm的CD-Ⅱ螺钉、TSRH螺钉和GSS螺钉的最大轴向拔出力分别只有6mm CD-Ⅱ螺钉的80％、82％和88％，各组ESFS螺钉最大轴向拔出力明显高于其它三种螺钉。差异有显著性（P〈0．01）。各组各螺钉最大旋入力矩之间差异无显著性（P〉0．05）。结论：ESFS螺钉具有很好的椎弓根锚固作用及翻修作用。     

不同矢状角度置入椎弓根螺钉的拔钉生物力学研究

目的 观察椎弓根螺钉不同矢状成角置入后单个椎体的拔钉生物力学特点,为临床置钉提供理论依据.方法 采用猪新鲜L1共12个椎体标本,将24侧椎弓根分三组,按不同矢状成角0°组、10°组、-20°组置人椎弓根螺钉,测出最大轴向拔出力.结果 -20°组椎弓根螺钉拔出力及拔出能量最大,0°组最小,10°组界于二者之间;三组之间最大拔出力及拔出能量两两比较P＜0.05.提示各组之间差异均有统计学意义.结论 矢状面成角置钉对螺钉的把持力大于0°角置钉,随置钉角度的增加,螺钉把持力也增大.     

锥形与柱形椎弓根螺钉的生物力学研究

目的 比较锥形与柱形椎弓根螺钉在下胸段及腰段的生物力学差异性及影响因素。方法 将6具成人新鲜T_9～L_5脊柱标本分解为 54个椎体标本。随机选取一侧按标准方法放置特制试验用直径5.5mm锥形螺钉,然后在MTS力学试验机上先后测量其最大扭矩及最大拔出力。在对侧以同样的方法进行5.5mm柱形螺钉的实验。结果在下胸段,锥形螺钉的最大扭矩(1.445 ±0.66)N·m显著性大于柱形的最大扭矩(1.073±10.42)N·m(P=0.021),而在腰段锥形(1.017±0.43)N·m和柱形(1.28±0.50)N·m螺钉的最大扭矩没有明显差异(P=0.416)。无论在下胸段还是腰段,锥形螺钉与柱形螺钉的最大拔出力均无显著性差异。从下胸段到腰段,螺钉的最大拔出力逐步增加。柱形椎弓根螺钉的最大扭矩与最大拔出力呈正相关(r=0.629)锥形螺钉的最大扭矩与最大轴向拔出力的相关性不显著(r=0.179)。结论 相同直径的锥形与柱形螺钉的最大拔出力相近,且锥形螺钉在其直径与椎弓根内径相近时具有较高的扭矩。螺钉的最大扭矩与最大拔出力的相关关系要视螺钉的类型而定。     

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.