下颈椎经关节螺钉植入深度的侧位X线片评价

目的 运用侧位x线片评价下颈椎经关节螺钉植入深度的安伞性.方法 采用6具新鲜颈椎标本(C1～T1),每具标本均在直视下植入下颈椎经关节螺钉(每侧4枚螺钉:C3,4、C4,5、C5,6、C6,7各1枚),分别在植入螺钉尖端穿出最后一层皮质0、2、4、6 mm时摄标准侧位x线片,将侧位X线片上椎体垂直等分为四部分,定义为1～4区,并定义椎体后缘之后相当宽度的区域为前1区.每次植入时记录螺钉尖端在X线侧位片的位置,以综合评价螺钉植入的安全性.结果 在C3,4和C4,5螺钉尖端穿出最后一层皮质0 mm时,87.5％在1区,穿出2 mm时,54.2％在1区.当螺钉尖端穿出4 mm时,75.O％在2区,穿出6mm时58.3％在3区.在C5,6和C6,7,穿出0mm时75.0％位于前1区,穿出2mm时,54.2％位于前1区;穿出4 mm时83.3％位于1区,穿出6mm时,50.0％位于2区.结论 侧位X线片町用于评价下颈椎经关节螺钉植入深度的安全性.在侧位X线片上,理想的螺钉尖端位置为C3,4和C4,5应位于1区,而在Cs,6和C6.7应位于前1区.     

基于X线片的十二等分法评估全椎弓根螺钉固定矫形术治疗青少年特发性脊柱侧凸的置钉准确性

目的 :利用基于X线片的十二等分法评估单纯后路全椎弓根螺钉固定矫形术治疗青少年特发性脊柱侧凸(adolescent idiopathic scoliosis,AIS)的置钉准确性。方法:回顾性分析我科行单纯后路全椎弓根螺钉固定矫形术治疗的AIS患者40例(女性34例,男性6例),年龄15.2±1.9岁(11～18岁),分别采用传统方法和十二等分法在X线片上评估椎弓根螺钉置钉准确性,并通过CT平扫验证。传统方法:A级,螺钉钉尖在椎弓根内壁和椎体中线之间,且与相邻螺钉相比无明显偏内或偏外;B级,螺钉钉尖超越椎体中线或与相邻螺钉相比明显偏内;C级,螺钉钉尖在椎弓根内壁以外或与相邻螺钉相比明显偏外。十二等分法:将椎体由凹侧外侧缘及凸侧外侧缘向分别正中线画等分线分12等份,并根据螺钉钉尖在所在椎体上的位置和椎体旋转的程度确定相应的安全范围。A级,螺钉钉尖在安全范围内;B级,螺钉钉尖超出安全范围内界或与相邻螺钉相比明显偏内;C级,螺钉钉尖超出安全范围外界或与相邻螺钉相比明显偏外。CT平扫:A级,螺钉全部在椎弓根内;B级,螺钉有任何部分超出椎弓根内壁;C级,螺钉有任何部分超出椎弓根外壁。通过卡方检验和诊断试验结果法对比两种X线片评估方法的准确性。结果:CT平扫评估,638枚螺钉中595枚(93.3%)A级,9枚(1.4%)B级,34枚(5.3%)C级;十二等分法,589枚(92.3%)A级,10枚(1.6%)B级,39枚(6.1%)C级;传统方法 ,582枚(91.2%)A级,19枚(3.0%)B级,37枚(5.8%)C级。使用传统方法误判螺钉49枚(7.7%)枚,十二等分法误判螺钉14枚(2.2%)枚,二者有显著差异(P0.001),其中B级误判的螺钉分别为25枚(3.9%)和5枚(0.8%)(P0.001),C级误判的螺钉分别为24枚(3.8%)和9枚(1.4%)(P=0.006)。此外,使用传统方法和十二等分法,评估凹侧椎弓根置钉的误判率高于凸侧,评估旋转较大椎体置钉的误判率高于旋转较小的椎体。结论:在X线片上采用十二等分法评估AIS患者的置钉情况简便、可靠,可以提高评估螺钉置钉的准确性。     

C型臂X线透视导航下腰椎椎弓根螺钉内固定手术

目的探讨C型臂X线透视电子计算机辅助导航下腰椎椎弓根螺钉内固定手术的优缺点。方法对16例腰椎管狭窄症患者进行全椎板减压,C型臂X线透视电子计算机辅助导航下行椎弓根螺钉内固定,横突间或小关节间隙植骨术。共置入76枚椎弓根螺钉,术后对所有病例行腰椎正侧位X线像检查,7例32枚螺钉行CT横断面扫描。从X线侧位像上判断螺钉与椎体骺板的成角,CT横断面判断螺钉的进钉位置与深度和螺钉与矢状面的角度。结果所有患者术后无明显神经根损害表现。X线侧位片上发现17枚螺钉与骺板不平行,形成6.3°±2.2°的成角,CT横断面发现32枚螺钉全部在椎弓根内,与椎弓根骨皮质最近距离平均1.7±0.6mm,钉尖距离前方骨皮质平均6.5±2.4mm。与矢状面成角7.2°～18.4°,但均未超出内外骨皮质。结论C型臂X线透视电子计算机辅助导航可提高螺钉置入准确率,明显减少操作者及患者的X线暴露。但只能获得二维图像,缺少横断面,不能准确指导进钉的深度和进钉与矢状面的角度。     

下颈椎侧块螺钉固定与椎动脉、神经根的解剖关系及评价

目的　通过解剖学研究和影像学手段 ,了解下颈椎侧块螺钉固定与椎动脉之间的关系以及斜位片在置钉过程中对神经根的监测价值。方法　 (1)取 2 8具尸体的C3 ～C7标本 ,年龄 2 8～ 79岁。摄取标本各椎体的横断面片 ,测量X线片上C3 ～C7横突孔外缘与侧块背面中心内侧 1mm处的连线在横断面上与矢状轴之间的成角。 (2 )取 10具标本 ,以侧块背面中心点内侧 1mm处为入针点、横突与侧块相交处为出针点在C3 ～C6侧块内置入克氏针。当针尖未超出或超出侧块远侧皮质 2、4、6mm时 ,摄取标本左右 4 5°斜位片。把斜位片上椎间孔分为上、下两部分 ,上部实际是真正的椎间孔 ,下部则相当于横突间孔位置。观察针尖在斜位片上椎间孔内的位置并计数 ,同时与实际解剖比较两者的一致性。　结果　 (1)C3 ～C6横突孔外缘与侧块背面中心内侧 1mm处的连线在横断面上与矢状轴成外偏 5°～ 12°的角度 ,椎体间差别无统计学意义 (P >0 0 5 )。 (2 )以横突与关节突相交处为出针点 ,实际观察当针尖超出侧块远侧皮质 2mm时 ,未突入横突间孔 ;当超出距离为 4、6mm时 ,针尖则突入横突间孔。X片上显示当针尖未超出远侧皮质时 ,斜位片上有 15 %针尖出现于椎间孔下部 ;当针尖超出 2mm时 ,斜位片 4 1 3%针尖出现于椎间孔下部 ;当针尖超出 4mm     

颈椎椎弓根螺钉徒手植入技术临床研究

目的：评价颈椎椎弓根螺钉徒手植入技术(无须术中影像技术引导)的安全性和可靠性。方法：作者应用Axis内固定系统(美国枢法模公司)对36例颈椎疾病患者进行颈后路经椎弓根内固定术,共植入螺钉144枚。椎弓根螺钉植入要点为：①术前仔细观察颈椎的侧位和双斜位x线片,并予以CT扫描以评估螺钉进针点、进针方向以及螺钉的长度及直径：②术中清晰地显露颈椎侧块和突间关节,用直径3．0mm高速球形磨钻去除侧块外卜象限处骨皮质,然后用2.0mm的自制手锥沿椎弓根事先确定的方向轻轻钻入,若遇阻力则需略改变方向,使其自然置入,深约2．0cm～2．5cm。确定无误后,则安置Axis钛板和置入长度合适的椎弓根螺钉;③安装完毕后,即用C掣臂作双斜位透视,无误后关闭切口。结果：从C3到C7,共植入根弓根螺钉144枚,其中10枚(6．8％)钉初次置入后感觉松动,经校正后二次置入成功,11枚(3．5％)钉道钻孔后出血较多,但及时处理后出血停止并无不良结果。术后X线斜位片及CT片显示,16枚(11．1％)螺钉穿破椎弓根,其中10枚(6．9％)螺钉穿破椎弓根外侧皮质,4枚(2,8％)钉穿破椎弓根上侧皮质,2枚(1．3％)钉穿破椎弓根卜侧皮质。随访未发现与螺钉置入穿破椎弓根皮质仃关的神经血管损伤问题。结论：本研究提示,在事先充分的埘每个患者颈椎椎弓根X线及CT解剖结构了解的情况下,徒手置入椎弓根螺钉行颈椎后路内同定是安全查行。     

脊柱腰段经椎弓根固定的影像表现实际差异

目的 :了解腰骶段椎弓根螺钉实际深度和影像表现的差异 ,为临床提供参考。方法 :通过 35例脊柱腰骶段模拟椎弓根固定术 ,对L4～S2 椎弓根螺丝钉实际深度和影像表现进行研究 ,证实其相关性和差异性。结果 :在螺钉实际透过椎体前方时 ,侧位片上有83 57%显示未透出 ,在L4更达 99 1 1 % ;与椎体前方的距离均在 1mm以上 ,最大达 8mm。结论 :当X线侧位片显示螺钉或克氏针与椎体前方骨皮质在 1 0mm左右时 ,针尖可能即将穿透骨皮质 ,当距离在 3 5～ 4mm左右时 ,则极有可能已透出椎体前方骨皮质。     

颈椎椎弓根螺钉徒手植入技术的临床研究

目的 评价颈椎椎弓根螺钉徒手植入技术（无须术中影像技术引导）的安全性和可靠性。方法应用Axis内固定系统（美国枢法模公司）对36例颈椎疾病患者进行颈后路经椎弓根内固定术,共植入螺钉144枚,方法如下：①术中清晰地显露颈椎侧块和突间关节,用直径3,0mm高速球形磨钻去除侧块外上象限处骨皮质,然后用2．0mm的自制手锥沿椎弓根事先确定的方向轻轻钻入,若遇阻力则需略改变方向,使其自然置入,深约2～2,5cm。确定无误后,则安置Axis钛板和置入长度合适的椎弓根螺钉。②安装完毕后,即用C型臂X线机作双斜位透视,无误后关闭切口。结果从G～G,共植入根弓根螺钉144枚,其中10枚（6．8％）钉初次置入后感觉松动,经校正后二次置入成功,11枚（3．5％）钉道钻孔后出血较多,但及时处理后出血停止并无不良结果。术后X线斜位片及CT片显示,16枚（11．1％）螺钉穿破椎弓根,其中10枚螺钉（6．9％）穿破椎弓根外侧皮质,4枚（2．8％）穿破椎弓根上侧皮质,2枚（1．3％）穿破椎弓根下侧皮质。随访未发现与螺钉置入穿破椎弓根皮质有关的神经血管损伤问题。结论本研究提示,在事先充分的对每个患者颈椎椎弓根X线及CT解剖结构了解的情况下,徒手置入椎弓根螺钉行颈椎后路内固定安全可行。     

下颈椎经关节螺钉和Magerl侧块螺钉与脊神经关系的解剖学比较

目的对比下颈椎经关节螺钉和Magerl侧块螺钉固定技术神经根(前支和后支)损伤的潜在风险。方法应用经关节螺钉和Magerl侧块螺钉两种固定技术,固定C_(3-7)节段,每种技术使用2具标本和20枚螺钉。使用直径为3．5mm、长度为20mm的螺钉进行过度穿透侧块腹侧皮质固定。仔细解剖颈部的前侧方,观察螺钉与脊神经前、后支的关系。结果下颈椎经关节螺钉固定技术总体神经损伤比例(45%)明显低于Magerl侧块螺钉固定技术(90%),两者差异有显著性意义(P＜0．05)。经关节螺钉和Magerl侧块螺钉固定技术引起的神经损伤均最多见于脊神经后支,分别为25%和45%。结论经关节螺钉固定技术神经根损伤的风险低于Magerl侧块螺钉固定技术。     

透视下分步引导上中胸椎椎弓根螺钉安全植入实验研究

目的：探索C形臂X线监测引导上中胸椎椎弓根螺钉植入的的方法,并评定其准确性与安全性。方法：①取6具正常成人T1-T8脊椎骨架标本,分解出单个椎体,导针沿椎弓根轴线进针,分别于进针点、针前端位于椎弓根中部、椎体后缘及椎体前缘皮质下,通过C形臂X线透视,记录、分析椎弓根轴线导针在进针点及不同进针深度时在正侧位透视图像上导针前端的位置,以及相关位置对应关系变化规律。②按上述椎弓根轴线导针C形臂X线透视监测对应位置变化规律,作为C形臂X线透视下分步引导上中胸椎椎弓根螺钉安全植入的方法。取6具T1-T8脊柱标本,C形臂X线机引导下分步植入椎弓根螺钉96枚,然后将脊椎标本作CT扫描,判定椎弓根螺钉位置。结果：根据CT扫描结果,优（椎弓根螺钉安全位于椎弓根内者）90枚,可（螺钉穿破椎弓根内或外侧骨皮质较少,突破在2mm以内者）6枚,差（螺钉穿破椎弓根内外骨皮质较多,突破在2mm以上）0枚。结论：C形臂X线透视下分步引导上中胸椎椎弓根螺钉植入,是一种能提高上中胸椎椎弓根螺钉植入的简单经济、确实可行的方法。     

颈椎斜位X线片在颈椎椎弓根钉固定中应用的研究

目的：探讨通过颈椎斜位X线片观察椎弓根的位置和方向,及其在判断椎弓根钉固定中准确,安全地进行钉的作用。方法：人尸体颈椎30例,其中椎动脉造影8例,椎动脉脊髓同时造影6例,根据术前X线斜位片,结合解剖标记定位,选择是钉点及进行钉方向,将直径3．5mm、长度24mm的不锈钢螺钉固定于C2或C3－C6或C7椎弓根中,共160枚,通过术后斜位X线片中判断螺钉在椎弓根的位置,并与CT扫描结果对照,以肯定X线的判断,结果：螺钉位置方向正确者152枚,X线片与CT扫描片的判断完全相符;X线判断螺钉偏向椎弓根外侧边缘5枚,偏向椎弓根内侧的边缘3枚。CT扫描确位于椎弓根外侧边缘3枚,怀疑进入椎动脉孔的2枚;在椎弓根内侧边缘没有进入椎管的3枚。结论：术前通过X线斜位片基本可以解椎弓根方向,上下径;通过术后X线斜位片可较为准确地判断椎弓根钉在椎弓根内的位置及有无进行推动脉孔、椎管的情况,X线与CT的结果差异可能与CT扫描的角度及其伪影有关,该方法简单易行。     

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 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.     

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.     

Is the recovery profile of mivacurium independent of the rate of decay of its plasma concentration in patients with normal plasma cholinesterase activity?

Background: The duration of action of muscle relaxants is poorly correlated to the rate of decay of their plasma concentration. The plasma concentration of mivacurium may rapidly decrease below its active concentration because of the extensive hydrolysis of mivacurium. By inflating a tourniquet on one upper limb for 3 min after the administration of atracurium, mivacurium or vecuronium, we studied the influence of the initial decline of their plasma concentration on their effect. Methods: In 50 patients anaesthetised with thiopental, isoflurane and fentanyl, the effect of bolus doses of 0.15 or 0.25 mg . kg^?1 mivacurium (MIV 15, MIV 25), 0.3 or 0.5 mg . kg^?1 atracurium (ATR 30, ATR 50) and 0.06 or 0.1 mg . kg^?1 vecuronium (VEC 06, VEC 10) were measured on both arms (evoked response of the adductor pollicis to train-of-four stimulation every 12 s), a tourniquet being applied on one arm just before and during 3 min after the muscle relaxant bolus. Results: Tourniquet inflation of 3 min almost abolished the neuromuscular effect of mivacurium. In the vecuronium groups and in the ATR 50 group, tourniquet inflation did not modify the maximum degree of depression of the twitch response. Also, the duration of action of vecuronium was unaffected by the tourniquet. In the ATR 30 group, times to return of the twitch response to 25% (duration 25%) and 75% (duration 75%) of control response were significantly shorter in the cuffed arm, 23 min vs 27 min, and 41 min vs 45 min, respectively. In the ATR 50 group, only duration 25% was significantly shorter in the cuffed arm (41 min vs 45 min). Conclusion: The results suggest that the rate of decline of the plasma concentration of mivacurium is so rapid, that a very low and almost clinically ineffective concentration is present as soon as 3 min after its administration. The results also indicate that the recovery from a mivacurium-induced neuromuscular blockade is not influenced by the rate of decay of its plasma concentration in patients with genotypically normal plasma cholinesterase.     

Membranes in Artificial Organs

Abstract: Membrane processes play a pivotal and enabling role in modern replacement therapy for acute and chronic organ failure and in the management of immunologic diseases. In fact, virtually all contemporary extracorporeal blood purification methods employ membrane devices, and the next generation of artificial organs and tissue engineering therapies are almost certain to be similarly grounded in membrane technology. In this short essay, we comment on the similarities and differences among synthetic membranes and their natural counterparts and also provide a critical overview of the demographics and technology of hemodialysis, hemofiltration, apheresis, oxygenation, and emerging membrane technologies and applications.     

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.     

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.     

Intrathecal administration of sameridine to patients subjected to arthroscopic knee joint surgery

Background: Sameridine, a new substance with both local anesthetic and opioid effects, was administered intrathecally for the first time to humans, i. e. in patients subjected to arthroscopic knee joint surgery.
Method: A dose-escalating (10, 15, 20 and 25 mg), open study was performed in 33 patients. Only two patients were included in the 25 mg group.
Results: Sameridine provided good quality of surgical anesthesia in all patients except those receiving 10 mg. The maximum level of sensory block, Th5–Th7, was reached within 30 min with a median duration of 3.6–3.9 h. The motor block was more profound with increasing dose, but never lasted longer than the sensory block. The influence on heart rate and blood pressure was minor and atropine and ephedrine were needed in four patients. No clinically significant ECG-changes were detected and no arrhythmias were recorded. Oxygen saturation and respiratory rate did not decrease in a clinically significant way and were not affected by concomitant morphine given i. v. postoperatively. There were few side-effects, the most frequent being mild pruritus (10/33).
Conclusion: Sameridine provided clinically adequate anesthesia for the patients receiving the doses of 15, 20 and 25 mg. Further studies are needed to evaluate the substance and it is of great interest to clinically investigate the opioid component with respect to postoperative analgesia.     

Reduction of Plasma Fibrinogen, Immunoglobulin G, and Immunoglobulin M Concentrations by Immunoadsorption Therapy with Tryptophan and Phenylalanine Adsorbents

Abstract Immunoadsorption (1A) therapy with tryptophan (TR-350) or phenylalanine (PH-350) adsorbents has been used to reduce the concentration of serum antibodies in human lymphocyte antigen (HLA)-immunized patients. Other forms of plasma purification have been reported to reduce the level of fibrinogen, which affects the blood properties. In this study we investigated the effects of IA therapy using both adsorbents on plasma fibrinogen and immunoglobulins G and M in 13 patients (8 patients were treated with TR-350, and 5 patients were treated with PH-350). During each session 1 plasma volume (2.8 ± 0.4 L of plasma) was processed through the immunocolumn and then returned to the patient together with the blood cells. Compared with the pretreatment values, the plasma fibrinogen, IgG, and IgM concentrations were significantly reduced after IA therapy (p < 0.01 for TR-350; p < 0.04 for PH-350). There was a positive correlation between the degree of reduction of plasma proteins and the number of IA treatments given. A nonpara-metric test (Wilcoxon's signed-rank test or the Mann-Whitney test) was used for statistical analysis. We conclude from our study that IA therapy effectively lowers the plasma levels of fibrinogen, IgG, and IgM and thus can be considered a valuable alternative to other blood purification methods.