单束单隧道与双束双隧道重建膝前交叉韧带的生物力学对比研究

[目的]研究双束股骨双隧道法重建前交叉韧带(ACL)恢复膝关节前后方向稳定性的能力,并与单束单隧道重建法进行生物力学性能的比较。[方法]应用跟腱分别采用双束股骨双隧道、单前内侧束和单后外侧束三种方法对10个新鲜尸体膝关节进行前交叉韧带重建。术后分别于膝关节屈曲0°、15°、30°、60°及90°时对胫骨施行±100 N的作用力,测量胫骨相对于股骨移动的距离。[结果]在屈膝角度较小(0°~30°)的情况下,单前内侧束重建法术后胫骨的移动距离与完整标本接近(P>0.05);但屈曲超过30°,特别是超过60°后,单前内侧束重建法术后胫骨移动的距离明显大于完整标本(P<0.05)。在屈膝角度<60°的情况下,单后外侧束重建法胫骨移动的距离明显大于完整标本(P<0.05):但屈曲超过60°胫骨移动的距离与完整标本接近(P>0.05);在膝关节的整个屈曲范围(0°~90°)内,双束股骨双隧道重建法术后胫骨移动的距离与完整标本接近(P>0.05)。[结论]双束股骨双隧道重建法,在膝关节的整个屈曲范围(0°~90°)内,比单束股骨单隧道重建法能更有效的恢复膝关节的稳定性。     

股骨单隧道内分叉双束纤维重建后交叉韧带的实验研究

目的在人膝关节标本上行股骨单隧道分叉双束纤维重建后交叉韧带(posterior cruciate ligament,PCL),探讨其术式的优缺点。方法应用力学试验机对14侧捐赠新鲜冷冻人膝关节标本进行生物力学测试,男12侧,女2侧;年龄20～31岁。标本股骨段长20cm,胫骨段长20cm。首先测量PCL完整时胫骨后移距离和交叉韧带的应变(完整组,n=14);然后切断PCL(切断组,n=14),测量胫骨受力时的后移距离后,再将标本随机分为两组:单束重建组(n=7)和分叉双束重建组(n=7),分别测量屈膝0、30、60、90和120°5个角度时胫骨后移距离和移植韧带的应变。结果胫骨受到100N后向力量,完整组在不同屈膝角度下,胫骨向后移位1.97±0.29～2.60±0.23mm,前外束和后内束纤维交替紧张松弛。切断组膝关节明显松弛,胫骨向后移位达11.27±1.06～14.94±0.67mm,与完整组比较差异有统计学意义(P<0.05);单束纤维重建组,在不同屈膝角度下胫骨向后移位1.99±0.19～2.72±0.38mm,移植韧带持续紧张。双束纤维重建组在不同屈膝角度下胫骨向后移位2.27±0.32～3.05±0.44mm,移植的双束纤维交替紧张,协同作用。组内比较:双束重建组在不同屈膝角度时胫骨向后位移差异无统计学意义(P>0.05),而单束重建组在屈膝90°时与屈膝30、60和120°时相比,胫骨后移增大,差异有统计学意义(P<0.05)。结论股骨单隧道内分叉双束纤维重建PCL术在各屈膝角度均能有效防止胫骨后移,股骨单隧道单束重建术屈膝90°时后移较其他角度时增大。分叉双束重建PCL的两束纤维束交替紧张,生物力学特征更接近于正常PCL。     

关节镜下股骨单隧道与双隧道重建后十字韧带的疗效分析

目的分析比较关节镜下单束单隧道与双束股骨双隧道重建后十字韧带(PCL)术后的临床效果。方法1999年1月～2001年12月,采用单束前外束重建法重建PCL 18例,男14例,女4例;年龄18～50岁,平均35.5岁;右膝12例,左膝6例。移植物为骨-髌腱(中1/3)-骨的11例,半腱肌腱和股薄肌腱的7例。于PCL股骨附着点解剖中心的稍前方钻取股骨隧道,屈膝70°,拉紧并固定移植物。2000年1月～2002年12月,采用双束股骨双隧道法重建PCL12例,男10例,女2例;年龄21～47岁,平均33岁;右膝9例,左膝3例。移植物为半腱肌腱和股薄肌腱的7例,一端带髌骨块的股四头肌肌腱的5例。将肌腱编织分为两束。于股骨侧钻取双隧道。两束分别于屈膝70°和0°时拉紧并固定。结果采用前外束重建法的18例患者平均随访23个月,采用双束股骨双隧道重建法的12例患者平均随访17个月。前外束重建组与双束股骨双隧道重建组随访时的Lysholm评分分别为(92.4±3.7)分和(94.3±3.4)分,两组间差异无显著性(P>0.05)。屈膝0°和30°时,前外束重建组的胫骨后移距离是(5.9±0.4)mm和(6.2±0.5)mm,双束股骨双隧道重建组是(3.5±0.3)mm和(4.0±0.4)mm,两组间差异有显著性(P<0.05);屈膝60°和90°时,两组胫骨后移距离差异无显著性(P>0.05)。结论双束股骨双隧道重建PCL的方法优于前外     

单隧道双束和单束ACL重建的生物力学比较研究

目的比较单隧道双束和单隧道单束ACL重建膝关节稳定性的差异。方法选用6侧人体膝关节标本,保留完整的关节囊及周围韧带,行单隧道双束和单束ACL重建,在MTS-858生物材料试验系统上测试膝关节在胫前加载(134N)和旋转加载(5N·m内旋胫骨)下屈曲0°、15°、30°、60°、90°位时的运动学反应。每个膝关节在4个不同条件下进行测试:ACL完整、ACL损伤、单隧道双束重建ACL以及单隧道单束重建ACL,其中单隧道双束及单束ACL均采用双股腘绳肌腱。结果 (1)胫前加载:双束组在屈曲30°、60°和90°位,单束组在屈曲90°位时关节前后稳定性获得良好恢复(P0.05);在屈曲60°位时双束组的胫前位移明显低于单束组,差异有统计学意义(P0.05)。(2)旋转加载:与ACL完整组相比较,双束组的胫骨内旋角度在屈曲0°、60°位时无明显变化(P0.05),屈曲90°位时明显减少(P0.05);单束组在屈曲0°时无明显变化(P0.05)。屈曲60°和90°位时双束组的胫骨内旋角度明显小于单束组,差异有统计学意义(P0.05)。结论与单隧道单束ACL重建相比,单隧道双束ACL重建能够更好地恢复膝关节前后稳定性及旋转稳定性。     

挤压螺钉固定自体髌韧带移植重建后交叉韧带的生物力学研究

目的:评价挤压螺钉固定自体骨-髌韧带-骨(bone-patellar-bone,B-PT-B)移植重建后交叉韧带(posterior cruciate ligament,PCL)术提供的膝关节胫骨后移刚度和强度,为手术后康复计划的制定提供依据。方法:对正常和挤压螺钉固定自体B-PT-B移植重建PCL术后等状态的新鲜尸体标本,进行膝关节屈曲15°。30°、90°位胫骨后移刚度和屈膝90°位胫骨后移强度测试。结果:挤压螺钉固定自体B-PT-B移植重建PCL术后,各膝关节屈曲角度时胫骨后移刚度明显大于正常状态,以90°时最为明显;胫骨后移强度则明显小于正常状态,约为其25％。结论:挤压螺钉固定自体B-PT-B移植重建PCL术后早期不宜负重,功能锻炼膝关节屈曲不超过90°。     

挤压螺钉固定自体髌韧带移植重建后交叉韧带的生物力学研究

目的评价挤压螺钉固定自体骨-髌韧带-骨(bone-patellar-bone,B-PT-B)移植重建后交叉韧带(posterior cruciate ligament,PCL)术提供的膝关节胫骨后移刚度和强度,为手术后康复计划的制定提供依据.方法对正常和挤压螺钉固定自体B-PT-B移植重建PCL术后等状态的新鲜尸体标本,进行膝关节屈曲15°、30°、90°位胫骨后移刚度和屈膝90°位胫骨后移强度测试.结果挤压螺钉固定自体B-PT-B移植重建PCL术后,各膝关节屈曲角度时胫骨后移刚度明显大于正常状态,以90°时最为明显;胫骨后移强度则明显小于正常状态,约为其25%.结论挤压螺钉固定自体B-PT-B移植重建PCL术后早期不宜负重,功能锻炼膝关节屈曲不超过90°.     

关节镜下股骨双隧道双束腘绳肌肌腱重建后十字韧带

目的探讨关节镜下采用可吸收界面螺钉固定双束腘绳肌肌腱,股骨双隧道重建后十字韧带(PCL)的方法和疗效。方法24例PCL损伤患者,年龄为17￣42岁,平均32岁。在关节镜下应用可吸收界面螺钉固定,股骨双隧道胫骨单隧道双束腘绳肌肌腱重建PCL。3股半腱肌肌腱在屈膝15°￣30°位拉紧、固定,重建前外侧束;3股股薄肌肌腱在屈膝60°￣70°位拉紧、固定,重建后内侧束。结果24例患者术后随访6￣19个月,平均9.4个月。术后膝关节活动度均在正常范围,无疼痛,无创伤性关节炎。后抽屉试验、反向Lachman试验、胫骨结节塌陷征和反向轴移试验均为阴性,术后Lysholm评分为(92.7±6.4)分,较术前(49.4±9.3)分有显著提高(t=3.12,P<0.01)。术后Tegner活动评分为(6.7±1.4)分,较术前(3.2±0.9)分有显著提高(t=3.13,P<0.01)。结论股骨双隧道胫骨单隧道双束自体腘绳肌肌腱重建PCL能够较好的重建膝关节在不同伸屈角度的稳定性。生物可降解螺钉为PCL重建的理想的内固定材料。     

单束重建与解剖双束重建治疗内侧副韧带Ⅲ级损伤的生物力学比较研究

目的比较单束重建与解剖双束重建治疗膝关节内侧副韧带(medial collateral ligament,MCL)Ⅲ级损伤后膝关节稳定性差异,为临床MCL损伤治疗提供生物力学参考。方法取自愿捐赠的成人新鲜膝关节标本9具,随机分为3组(n=3)。其中,正常MCL组仅行前交叉韧带(anterior cruciate ligament,ACL)离断并单束重建,保留完整MCL。单束重建组及双束重建组均离断ACL、MCL浅层(superficial MCL,sMCL)及后斜韧带(posterior oblique ligament,POL),制备MCLⅢ级损伤模型;ACL单束重建后,分别行sMCL单束重建、sMCL及POL解剖双束重建。采用生物材料动态力学试验机测量各组膝关节完全伸直位及屈曲不同角度时,胫骨前方移位距离(anterior tibial translation,ATT)、胫骨内旋角(internal rotation,IR)、胫骨外翻角(valgus rotation,VAL),以及内旋及外翻力矩作用下MCL及ACL受力情况。结果膝关节完全伸直位及屈曲15°、30°、45°、60°、90°位时,3组ATT差异均无统计学意义(P0.05)。单束重建组膝关节完全伸直位及屈曲15°位时IR及VAL,以及屈曲30°位时VAL,均明显大于双束重建组及正常MCL组(P0.05);双束重建组与正常MCL组差异均无统计学意义(P0.05)。膝关节完全伸直位及屈曲15°、30°位时,内旋、外翻力矩作用下,3组MCL及ACL受力差异均无统计学意义(P0.05)。结论相比单束重建,解剖双束重建治疗MCLⅢ级损伤可以更好地恢复膝关节的外翻及旋转稳定性。     

负荷条件下前交叉韧带的股骨重建位置

目的　探讨模拟生理负荷条件下前交叉韧带股骨等距重建位置。方法　 7具新鲜冷冻膝关节标本 ,在前交叉韧带股骨附着区取 5点以及胫骨附着区中点分别钻骨隧道 ,通过钢丝和等距测量器施加初负荷 ,检测膝关节屈曲过程中胫骨和股骨隧道间的距离变化。结果　膝关节 0°～ 90°屈曲过程中 ,股骨韧带附着区中点、后点和下点与胫骨附着区中点间呈等距变化 ,而股骨韧带附着区前点和上点与胫骨附着区中点间距离变化超过生理等距界限。结论　股骨韧带附着区后点和下点是理想的前交叉韧带股骨等距重建点。股骨韧带附着区中点、后点和下点的连线构成了前交叉韧带的股骨等距重建区。     

关节镜下股四头肌腱-骨双束股骨双隧道重建膝后十字韧带

目的探讨股四头肌腱-骨(QT-B)双束股骨双隧道重建膝后十字韧带(PCL)的方法与疗效.方法共32例PCL损伤患者,男28例,女4例;年龄19～47岁,平均29.8岁.急性损伤14例,慢性损伤l8例.取自体同侧QT-B,制备成"Y"形双束移植物,通过关节镜行前外与后内束股骨双隧道PCL重建,分别在屈膝90°和30°位拉紧、固定PCL前外与后内束.结果 32例均获得13～27个月(平均153个月)的随访.后抽屉试验后方不稳定较术前平均恢复1.1度.国际膝关节评分委员会(IKDC)评分A级9例(28%),B级19例(59%),C级3例(9%),D级1例(3%).Lysholm-Tegner膝关节功能综合评定分别由术前的(61±5)分和(3.9±1.8)分升至(90±8)分和(7.8±1.7)分.屈膝25°和90°KT-2000测定胫骨后移由术前平均(12.9±2.9)mm和(13.8±3.6)mm,减少为术后(4.9±2.0)mm和(5.7±2.6)mm;健患侧胫骨后移差异由术前平均(7.9±1.4)mm和(8.5±1.8)mm,改善至术后(2.9±0.8)mm和(3.3±1.0)mm.结论PCL双束双隧道重建可更好地恢复膝关节在不同屈伸角度的稳定性,QT-B是双隧道重建的理想移植物.     

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.     

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.     

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.