单纯减压对皮神经卡压作用的实验研究

目的:在大鼠皮神经卡压模型的基础上观察单纯减压术对皮神经卡压的作用,以探讨铍针治疗皮神经卡压综合征的理论依据。方法:用内径0.4 mm的硅胶管卡压大鼠双侧隐神经1周,以建立皮神经卡压模型。然后去除左侧隐神经上的硅胶管作为减压侧,保留右侧隐神经上的硅胶管作为卡压侧。将28只大鼠随机分成3组,A组(n=10):减压术后1周进行实验研究;B组(n=10):减压术后3周进行实验研究;C组(n=8):仅以硅胶管卡压隐神经1周,不进行减压。各组均进行大体形态观察、电生理学检测和组织学检测。结果:A组和B组卡压侧的组织学和电生理学改变与C组相比均明显加重,而且B组卡压侧的改变比A组卡压侧更为严重。相反A组和B组减压侧的组织学和电生理学改变与C组相比均有明显的恢复,且B组减压侧的恢复优于A组减压侧。结论:①单纯的减压术可使受压皮神经的组织学和电生理学得到较好的改善;②皮神经卡压损伤程度与卡压时间相关,卡压时间越长损伤越重,及早去除卡压因素有利于损伤神经的结构再生和功能恢复。     

结缔组织生长因子在周围神经慢性卡压损伤中的表达及其意义

目的 探讨大鼠坐骨神经慢性卡压损伤后其卡压神经段内结缔组织生长因子(CTGF)表达变化及其意义. 方法 2010年7月到2010年9月,将50只成年雄性SD大鼠随机分成:A组(假手术组),仅分离暴露坐骨神经;B组(卡压组),采用Mackinnon建立的坐骨神经卡压模型方法对大鼠右侧后腿坐骨神经行硅胶管卡压术.于卡压术后2、4、6、8、10周时间点,随机取A、B组大鼠各5只,取其卡压段坐骨神经行组织形态学、免疫组织化学观察及RT-PCR、Western blot定量测定CTGF及Ⅰ、Ⅲ型胶原蛋白(COL-Ⅰ、Ⅲ)含量. 结果 坐骨神经慢性卡压损伤后,有髓神经纤维发生瓦勒变性,胶原纤维增生,CTGF表达上调,并伴有COL-I、Ⅲ表达升高,与假手术组比较差异有统计学意义(P＜0.05).结论 慢性卡压损伤可致周围神经发生纤维化病变,CTGF参与了这一病理生理改变过程,提示CTGF在周围神经纤维化过程中具有一定作用.     

大鼠臂丛神经慢性卡压后不同时程神经组织的超微结构研究

目的 探讨大鼠臂丛神经慢性卡压后不同时程神经组织的超微结构变化。方法 建立大鼠慢性卡压模型，对卡压后不同时程神经组织的细胞成分进行超微结构的量化分析，有髓神经纤维数目计数，测定髓鞘厚度、脱髓鞘神经纤维、空化神经纤维，以及观察巨噬细胞、新生有髓神经纤维。结果 慢性卡压神经的超微结构较正常神经有明显变化，但又与急性神经损伤有所不同：(1)有髓神经纤维数目在早期无明显减少，在中期明显减少，在后期虽然总数仍减少，但与中期相比却呈上升趋势，这与后期出现的新生有髓神经纤维有关。(2)髓鞘厚度一直呈下降趋势，并与卡压时程呈正相关。(3)巨噬细胞活性在卡压12周时明显增强，内含大量退变髓鞘及坏死神经轴突。(4)在卡压后16周组出现较多新生有髓神经纤维，但髓鞘结构发育不完善，髓鞘厚度较薄。结论 脱髓鞘改变即髓鞘厚度的变化是卡压神经组织的早期变化，神经轴突的变化(空化神经纤维)是卡压神经组织的晚期变化。神经的慢性卡压过程是神经纤维变性、坏死和神经纤维再生的两种相反方向的不平衡的动态变化过程，并以损伤占主导地位。     

周围神经卡压症显微外科治疗

自1981年以来应用显微外科技术治疗各类卡压症61例。其中43例经6个月－10年1个月的随访，结果优良率为87％，有效率为97．8％。对本症的病理、显微外科手术的治疗机理和适应证等进行了讨论。认为神经受压后在病理上可能比神经断裂后更复杂，除有理化改变和脱髓鞘改变外，也不能排除卡压的远端发生瓦勒变性、神经卡压段发生坏死和纤维化的可能。     

自体注射型富血小板纤维蛋白联合BMSCs治疗大鼠坐骨神经损伤的实验研究

目的探讨自体注射型富血小板纤维蛋白(injectable platelet rich fibrin,i-PRF)联合BMSCs治疗大鼠坐骨神经损伤的疗效。方法取10～15日龄SD乳鼠胫骨骨髓分离培养BMSCs至第4代备用。取24只成年SD大鼠眶后静脉血采用改良低速离心法制备i-PRF后,采用改良挤压损伤法制作坐骨神经Ⅲ度损伤模型后随机分为4组,每组6只。A、B、C、D组分别于损伤部位鞘膜内注射BMSCs悬液+自体i-PRF、自体i-PRF、BMSCs悬液、生理盐水。术后1～8周每周采用BBB评分法评价大鼠患肢神经功能恢复情况;术后2个月处死各组大鼠取材,行HE染色观察坐骨神经组织结构变化,透射电镜观察神经纤维、髓鞘、细胞核等细微结构改变,Western blot检测N-cadherin、巢蛋白(Nestin)、胶质纤维酸性蛋白(glial fibrillary acidic protein,GFAP)表达。结果术后大鼠均未发生免疫排斥反应及死亡。术后1周各组大鼠BBB评分比较差异无统计学意义(P0.05);术后2～8周,A组BBB评分显著高于B、C、D组,B、C组显著高于D组(P0.05),B、C组间差异无统计学意义(P0.05)。HE染色示,A组神经纤维排列整齐,无缺损及脱髓鞘改变;B组神经纤维结构欠清晰,轻度肿胀;C组神经纤维部分结构紊乱,局部脱髓鞘改变;D组神经纤维连续性欠佳,明显脱髓鞘改变,神经外膜部分缺损。透射电镜观察示,A组神经纤维结构清晰,髓鞘完整,细胞核致密;B组较A组稍次之;C组神经纤维结构模糊,有脱髓鞘改变;D组神经纤维结构紊乱,有脱髓鞘改变,神经外膜连续性中断。Western blot检测示,各组Nestin蛋白相对表达量比较差异均无统计学意义(P0.05)。B、C、D组N-cadherin蛋白相对表达量显著低于A组,C、D组低于B组,D组低于C组,差异均有统计学意义(P0.05)。B、C、D组GFAP蛋白相对表达量显著低于A组,D组显著低于B、C组,差异有统计学意义(P0.05);B、C组间差异无统计学意义(P0.05)。结论自体i-PRF与BMSCs联合使用可有效治疗大鼠坐骨神经损伤。     

周围神经卡压松解后病理生理变化的实验研究

目的 应用神经特殊染色技术及电生理学方法,探讨周围神经卡压松解后神经纤维的再生修复和神经传导功能的变化。方法 在大鼠坐骨神经卡压模型基础上,将６０只ＳＤ成年雄性大鼠随机分为四组。Ａ组：仅去除卡压;Ｂ组：去除卡压后切开神经外膜;Ｃ组：去除卡压后神经外膜下周围注射利美达松（０．５ｍｇ／ｋｇ）;Ｄ组：去除卡压后切开神经外膜,在神经周围注射利美达松（０．５ｍｇ／ｋｇ）。于去除卡压后１、２、３、４和５周行运     

颈交感神经在臂丛神经慢性卡压伤中的作用

目的 研究颈交感神经在臂丛神经慢性卡压伤中的作用.方法 24只雄性SD大鼠,随机分成A、B、C三组,每组8只.A组:臂丛神经下干慢性卡压模型;B组:臂丛神经下干慢性卡压模型,加颈中交感神经节切除;C组:对照组.3个月后,各组进行神经电生理检测第一骨间肌复合肌肉动作电位(CMAP),记录其波幅和潜伏期;切取臂丛神经下干卡压远侧3 mn神经干和C组臂丛神经下干,行甲苯脓蓝染色,半薄横切片,计数有髓神经纤维;切取C8、T1背根神经节,用RT-PCR方法检测背根节中P物质(SP) mRNA.结果 神经电生理检测CMAP波幅:A组(2.2± 1.1)mV,B组(3.9±1.1)mV,C组(8.6±2.0)mV;A组＜B组＜C组,差异有统计学意义(P＜0.01).潜伏期:A组(4.8±0.9)ms,B组(3.9±0.5)ms,C组(2.8±0.2)ms;A组＞B组＞C组,差异有统计学意义(P＜0.01).有髓神经纤维总数:A组(3583.0±540.0),B组(5098.0±742.0),C组(7934.0±868.0);A组＜B组＜C组,差异有统计学意义(P＜0.01).P物质mRNA表达水平:A组(3.6±0.8)×10-2,B组(2.2±0.7)×10-2,C组(1.2±0.3)×10-2;A组＞B组＞C组,差异有统计学意义(P＜0.01).结论 在交感神经作用下,臂丛神经慢性卡压伤的损伤程度加重,背根神经节中疼痛介质P物质表达增强,去交感神经有利于减轻臂丛神经慢性卡压伤损伤程度,有利于减轻因卡压引起的疼痛.交感神经激惹可能是臂丛神经慢性卡压性疾病发展的一个协同因素.     

不同浓度丁卡因或罗哌卡因对大鼠臂丛神经的毒性

目的 探讨不同浓度丁卡因和罗哌卡因对大鼠臂从神经的毒性.方法 成年雄性SD大鼠48只,体重410 ～ 430 g,采用随机数字表法,将其随机分为8组(n=6):生理盐水组(NS组)、0.25％、0.50％、1.00％丁卡因组(T1-3组)、0.25％、0.50％、1.00％、2.00％罗哌卡因组(R1-4组).随机选取一侧腋鞘,NS组注射生理盐水1.0 ml,T1-3组分别注射0.25％、0.50％、1.00％丁卡因0.5 ml,R1-3组分别注射0.25％、0.50％、1.00％罗哌卡因1.0 ml,R4组注射2.00％罗哌卡因0.5 ml.另一侧腋鞘作为对照.于注药后5d时检测臂从神经复合动作电位及其传导速度(NCV),并采用光镜和透射电镜观察臂从神经的病理学结果.结果 与对照侧和NS组比较,T2-3组和R3-4组臂丛神经复合动作电位降低,NCV减慢(P＜0.05);T1组、T2组和T3组臂从神经复合动作电位位依次降低,NCV依次减慢(P＜0.05);与R1-3组比较,R4组臂丛神经复合动作电位降低,NCV减慢(P＜0.05).病理学改变:T2组、T3组和R4组神经束膜明显水肿,髓鞘板层分离、断裂、重度脱髓鞘,轴突萎缩;R3组为“脱髓鞘”现象,髓鞘板层分离、断裂、重度脱髓鞘,轴突萎缩.结论 0.50％、1.00％丁卡因和1.00％、2.00％罗哌卡因可导致大鼠臂从神经产生病理性损伤,且损伤程度与其浓度有关.     

经雷公藤预处理大鼠异体神经移植后早期组织形态及免疫学观察

目的 观察经雷公藤预处理大鼠异体神经移植后髓鞘损伤程度及急性期免疫排斥反应,探讨雷公藤早期免疫抑制作用及合适用药浓度. 方法取60只3月龄雄性SD大鼠制备右侧坐骨神经干缺损模型,随机分为A、B、C、D、E组5组(n=12).取18只3月龄雄性Wistar大鼠,切取双侧坐骨神经干约15 mm,置入含200、400、800 mg/L雷公藤多甙细胞保存液(各浓度组浸泡12条神经),4℃下浸泡24 h,作为A、B、C组神经修复供体,修复神经缺损;另取6只3月龄Wistar大鼠,切取12条新鲜坐骨神经桥接于D组神经缺损处;E组将切下的自体坐骨神经立即行原位缝合.术后不同时间对移植神经行大体、光镜、电镜观察,检测髓鞘碱性蛋白(myelin basic protein,MBP)含量变化及免疫组织化学分析移植物CD4 、CD8 T细胞入侵情况. 结果 术后1周,A、B、C组神经纤维形态及结构较完整,炎性细胞浸润程度较D组轻;术后1、2、4周,A、B、C组组织形态学观察结果 相似,移植神经片段外形及结构清晰,与周围结缔组织粘连均较D组轻;术后48h及1、2、4周,各组均有不同程度髓鞘损伤,各时间点坐骨神经MBP含量B组最接近E组,两组差异无统计学意义(P＞0.05).术后1、4周,A、B、C组CD4 ,CD8 分子的IA值与D组比较,差异均有统计学意义(p＜0.05). 结论 雷公藤能有效降低异体神经移植术后早期急性排斥反应,对髓鞘发挥一定的保护作用.     

NGF对大鼠坐骨神经损伤后腰髓MBP含量及其前角神经元的影响

目的 :探讨NGF对大鼠坐骨神经完全离断后腰髓前角神经元的作用。方法 :30只大鼠分为 3组 ,Ⅰ组为生理盐水对照组 (硅胶管内注入 2 0ul生理盐水 ) ;Ⅱ组为NGF硅胶管给药 ,每只大鼠 10 0ng( 5ng/ul× 2 0ul) ;Ⅲ组为NGF硅胶管内给药后 +每日肌注NGF5 0 0ng/kg。切除单侧坐骨神经 10mm ,并用硅胶管桥接坐骨神经断端。术后 1、2、3、4个月分别进行霍乱毒素亚单位B结合的辣根过氧化酶 (CB -HRP)作为示踪剂 ,同时取标本测定脊髓髓鞘碱性蛋白 (MBP)含量。结果 :CB -HRP示踪Ⅱ和Ⅲ组优于对照组 ,前角运动神经元增多 ,突触连结成网 ;MBP含量Ⅱ组和Ⅲ组明显高于对照组 ,MBP含量减少不明显。结论 :外周神经损伤后 ,损伤局部应用NGF能减少其前角运动神经元死亡及脱髓鞘改变。     

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.