双侧关节突关节切除诱发椎间盘退变的磁共振计量分析

[目的]探讨新西兰大白兔腰椎关节突关节破坏诱发出椎间盘退变的核磁共振改变。[方法]30只新西兰大白兔,体重2.25~2.95kg,雄性。随机分为骨性手术组和软组织手术组。软组织手术组仅骨膜下剥离L3~7的椎旁肌肉;骨性手术组完整切除L4、5双侧下关节突和L5棘突,保留L5、L6上关节突。骨性手术组L4、5、L5、6椎间盘为实验组椎间盘,上下相邻的L3、4、L6、7为自身对照组椎间盘。软组织手术组L4、5、L5、6椎间盘为实验对照组椎间盘。术后1、2、4及8个月行核磁共振检查。将实验所得的L3、4、L4、5、L5、6、L6、7T2WI轴位像输入电脑,用KONTRONIBAS2.0全自动图像分析系统分析图像中高信号区域面积占整个椎间盘面积的百分比(面积分数)并进行统计分析。[结果]新西兰大白兔T2WI矢状位像上,髓核呈均一高信号。T2WI轴位像上,髓核高信号区域位于椎间盘中央,占椎间盘横截面积50%左右。养殖1个月与8个月面积分数比较无统计学差异。随着术后时间延长,实验组椎间盘轴位像上面积分数变化显著,自身对照组次之,实验对照组最小,相同时间3组之间比较有统计学差异,相同组别术后不同时间比较有统计学差异。[结论]脊柱失稳可以诱发椎间盘退变。髓核T2WI轴位像上面积分数减小能够较早反映出椎间盘退变。     

椎间失稳诱发椎间盘退变的病理学观察

[目的]探讨新西兰大白兔腰椎关节突关节破坏能否诱发椎间盘退变的组织学改变。[方法]30只新西兰大白兔,体重2.25~2.95kg,雄性。随机分为骨性手术组和软组织手术组。软组织手术组仅骨膜下剥离L3~7的椎旁肌肉;骨性手术组完整切除L4、L5双侧下关节突、L5棘突,保留L5、L6上关节突。骨性手术组L4、5、L5、6椎间盘为实验组椎间盘,上下相邻的L3、4、L6、7为自身对照组椎间盘。软组织手术组L4、5、L5、6椎间盘为实验对照组椎间盘。术后1、2、4、及8个月行光学显微镜、电子显微镜检查。[结果]正常新西兰大白兔椎间盘由纤维环、髓核组成,纤维环胶原纤维排列规则,软骨样细胞镶嵌其中。髓核组织由大量细胞外基质和散在的细胞组成。随着术后时间延长,实验组椎间盘纤维环胶原纤维排列紊乱,细胞数进行性减少。术后4个月,实验组椎间盘开始出现大量退变细胞,表现为外形不规则,细胞膜破裂,线粒体肿胀,细胞核位于周边,核浓缩,核膜皱缩,异染色质较正常增加,核仁消失。术后8周实验组椎间盘开始出现大量死亡细胞,表现为溶酶体明显增多,细胞核扭曲,粗面内质网扩张,线粒体空泡化,死亡细胞外周的“巢”增厚呈多层排列,致密颗粒增多。[结论]L4、5、L5、6关节突关节破坏导致椎间失稳,椎间失稳后可以诱发出椎间盘退变的组织学改变。     

实验性腰椎失稳致椎间盘退变的放射影像学观察

目的：探讨腰椎失稳对椎间盘的影响及其X线表现。方法：选用新西兰兔27只，随机分为手术组15只，对照组12只，手术组沿L3-L6棘突作后正中切口，剥离骶棘肌，切除棘上，棘间韧带，咬除关节突关节外后1/2，对照组作相同皮肤切口即缝合，分别于术后4，8个月对腰椎行X线检查，结果：除外手术组切口感染1只，术后2和5个月各死亡1只，其余兔存活完好至取材，术后4个月，手术组均发生腰椎后凸畸形，出现软骨终板钙化的椎间盘超过半数，8个月时，所有椎间盘软骨终板均钙化，多数椎间隙狭窄。对椎间隙楔形样变。椎间隙狭窄。终板钙化和骨赘形成4种退变征象发生频数的统计分析显示，手术组与对照组间的差异具有显著性意义。结论：脊柱稳定对保持椎间盘生理功能意义重大，脊柱失稳可诱发椎间盘退变，后凸畸形和软骨终板钙化是失稳诱发的腰椎间盘退变早先发生和常见的X线征象。     

腰椎间盘退变动物模型的建立

目的 制备椎问盘退变动物模型.方法 将48只新西兰大白兔随机分为骨性手术组和软组织手术组.骨性手术组L4L5、L5L6为实验组椎间盘,L3L4、L6L7为自身对照组;软组织手术组L4L5、L5L6为实验对照组椎问盘.术后1、2,4及8个月行MRI及分子生物学检查.结果 (1)MRI:兔髓核位于椎间盘中央,占椎间盘横截面积50%左右.术后1、2、4及8个月,3组椎间盘横断面T2高信号区域面积分数均逐渐减小(F=96.2～1544.4,P<0.01);术后相同时间段,实验组面积分数最小,自身对照组次之,实验对照组最高,差异有统计学意义(F=125.7～1850.6,P<0.01).(2)分子生物学:蛋白多糖、胶原为椎间盘主要细胞外基质,术后1、2、4及8个月,3组椎间盘蛋白多糖、Ⅱ型胶原表达量进行性下降(F=148.2～1544.4,P<0.01),Ⅰ型胶原表达量进行性上升(F=94.3～579.6,P<0.01).术后相同时间段,实验组蛋白多糖、Ⅱ型胶原最小,自身对照组次之,实验对照组最高(F=135.5～3520.6,P<0.01);Ⅰ型胶原表达量实验组高于实验对照组、自身对照组(F=7.8～143.1,P<0.01).结论 破坏关节突关节成功制备出椎间盘退变动物模型.     

兔椎间失稳软骨终板退变的实验研究

[目的]通过电镜研究软骨终板在椎间失稳环境下的退变过程,为椎间盘退变的治疗提供新的思路和方法.[方法]取48只6个月龄日本大耳白兔,雌雄不限,体重为(2.5±0.2)kg,随机进行分组,分为对照组和实验组,对照组为21只;实验组为27只;先将实验组兔腰背部皮毛剪除,用安定注射液1.25 mg/kg、氯胺酮0.02 g/kg、阿托品0.125 mg/kg顺次耳缘静脉注射麻醉后,俯卧固定于手术台上,用1%碘伏消毒手术区域,以髂嵴平对椎间隙(即L6.7)为中心,从正中取一长约4 cm纵行切口,切开皮肤及皮下组织,锐性分离,暴露棘突、椎板及上下关节突,将附着于棘突、椎板及小关节的肌肉全部分离开,然后依次切除L6.7棘上及棘间韧带,咬除第6腰椎两侧下关节突,造成椎间失稳,用无菌生理盐水冲洗切口,依次缝合各层组织;术后动物在笼中自由活动.实验组分别在术后2个月、4个月、6个月取材,对照组在相同条件下饲养后2个月、4个月、6个月取材;对椎间盘软骨终板用透射电镜观察软骨终板的结构,以综合判断软骨终板的退变过程.[结果]椎间失稳可导致椎问软骨终板胶原纤维结构由整齐有序、排列紧密向杂乱无章、排列松散退变.[结论]椎间失稳能明显导致椎间软骨终板的退变.     

兔椎间失稳软骨终板退变后弹性内固定作用的电镜实验研究

[目的]通过电镜观察研究弹性内固定重建椎间稳定的方法对软骨终板变化的作用机制,为椎间盘退变的临床治疗提供新的思路和方法。[方法]选取48只6个月龄日本大耳白兔,随机分组,分为实验失稳对照组和实验弹性内固定组,两组均为24只兔,将所有实验用兔进行手术椎间失稳;仅实验弹性内固定组在手术失稳2个月后用椎弓根螺钉和张力钢丝弹性内固定的方法进行L6、7的稳定性重建,均分别在内固定术后2、4、6个月取材。对椎间盘软骨终板用透射电镜观察,以判断软骨终板的退变过程。[结果]弹性内固定能明显阻止椎间盘软骨终板胶原纤维的退变,并可见软骨终板胶原纤维结构有部分恢复。[结论]弹性内固定能有效地阻止椎间盘软骨终板的退变;能有效促进软骨终板的修复。     

实验性椎间盘退变的放射影像学与病理学观察

目的 研究椎间盘退变过程中，椎间盘退变的放射影像学与病理学改变。方法 选用40只新西兰大白兔随机分为2组，实验组切除兔腰椎间棘间、棘上韧带及棘突、关节突，造成力学失稳状态诱导形成椎间盘退变模型。术后一周、3个月、8个月时摄腰椎正、侧位X线片，观察腰椎影像学变化。第3个月、8个月时取腰椎间盘，进行组织检查，评定椎间盘退变的病理改变情况。结果 模型建立后，3个月、8个月的X线片显现对照组无明显改变，实验组腰椎后突畸形，椎间隙狭窄，随着时间延长椎体软骨终板钙化更加明显。组织学观察发现，实验组随术后时间延长，髓核由椎间盘内脱出，并伴有椎间盘两侧软骨终板的纤维化即软骨终板发生退变。结论 椎体软骨终板的退变是椎间退变早期的主要表现方式。     

实验性椎间盘退变的放射影像学与病理学观察

目的　研究椎间盘退变过程中 ,椎间盘退变的放射影像学与病理学改变。方法　选用 4 0只新西兰大白兔随机分为 2组 ,实验组切除兔腰椎间棘间、棘上韧带及棘突、关节突 ,造成力学失稳状态诱导形成椎间盘退变模型。术后一周、 3个月、 8个月时摄腰椎正、侧位X线片 ,观察腰椎影像学变化。第 3个月、 8个月时取腰椎间盘 ,进行组织检查 ,评定椎间盘退变的病理改变情况。结果　模型建立后 ,3个月、 8个月的X线片显现对照组无明显改变 ,实验组腰椎后突畸形 ,椎间隙狭窄 ,随着时间延长椎体软骨终板钙化更加明显。组织学观察发现 ,实验组随术后时间延长 ,髓核由椎间盘内脱出 ,并伴有椎间盘两侧软骨终板的纤维化即软骨终板发生退变。结论　椎体软骨终板的退变是椎间退变早期的主要表现方式。     

椎间盘内注射TGF-β1对兔退变椎间盘软骨终板Ⅱ型胶原的影响

[目的]研究椎间盘内注射转化生长因子-β1(transforming growth factor-β1,TGF-β1)对兔退变腰椎间盘软骨终板Ⅱ型胶原的影响,以探讨局部注射 TGF-β1 对防治软骨终板退变的作用.[方法]选用 6 个月龄日本大耳白兔46只,雌雄不限,体重为(2.5±0.2)kg,随机分为对照组、预防组和治疗组.对照组 18 只,预防组 18 只,治疗组 10 只.所有实验动物均通过切开皮肤及皮下组织,剥离骶棘肌、切断 L5.6、L6.7棘上、棘间韧带、两侧关节突关节囊及关节后外 1/2 造成 L5.6、L6.7椎间失稳模型.预防组动物在完成椎间失稳手术后立即于同一切口通过侧后方入路显露 L5.6、L6.7椎间盘,并在椎间盘内注射 TGF-β1.对照组及预防组分别于椎间失稳术后 3、6 个月各 8 只取材.治疗组于椎间失稳术后第 3 个月再行侧后方入路 L5、6、L6、7椎间盘内注射 TGF-β1,第 6 个月取材.运用免疫组织化学方法对标本进行Ⅱ型胶原测定,并用SPSS 15.0 软件进行统计学分析.[结果]①术后 3、6 个月预防组软骨终板内Ⅱ型胶原与对照组相比有高表达,差异有显著统计学意义;②术后第 6 个月治疗组软骨终板内Ⅱ型胶原与对照组相比有较高表达,差异有显著统计学意义.[结论]在兔椎间盘内注射 TGF-β1 可以提高Ⅱ型胶原的表达,具有延缓软骨终板退变的作用.     

腰椎关节突关节骨性关节炎对腰椎稳定性的影响

目的探讨腰椎退变过程中,腰椎间盘退变、关节突关节骨性关节炎与腰椎稳定性之间的关系.方法对78名腰椎退变患者进行腰椎MRI和动力位X线摄影.腰椎不稳分为椎间角度运动不稳、旋转不稳和椎间位移不稳,其中椎间位移不稳细分为前向不稳、后向不稳和前后向不稳.腰椎间盘退变依据矢状位T2加权像分为5级;关节突关节骨性关节炎依据水平位T1加权像分为4级.对资料进行统计分析.结果腰椎椎间角度运动不稳和前后向椎间位移不稳与关节突关节骨性关节炎存在显著负相关,前向椎间位移不稳与腰椎关节突关节骨性关节炎和椎间盘退变呈显著正相关,腰椎矢状面旋转不稳与腰椎关节突关节骨性关节炎无显著相关.结论腰椎间盘退变和腰椎关节突关节骨性关节炎可影响腰椎运动节段的稳定性.     

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.