选择性椎弓根置钉矫形治疗青少年特发性脊柱侧凸

[目的]回顾性观察分析后路选择性椎弓根置钉矫形治疗青少年特发性脊柱侧凸(AIS)的临床疗效。[方法]2005年1月～2009年6月采用后路选择性椎弓根置钉矫形手术治疗AIS,测量术前和术后胸侧凸冠状面Cobb角、矢状面Cobb角,腰侧凸冠状面Cobb角,顶椎椎体旋转和身高变化。分析临床疗效。[结果]手术时间平均186min;术中失血量平均800 ml。术中无脊髓、神经及血管损伤,术后无胸腔积液及切口感染。随访2.1～6.4年,平均3.6年。胸侧凸冠状面Cobb角、胸侧凸矢状面Cobb角和冠状腰弯Cobb角分别由术前57.38°±10.93°、29.3°±7.8°、33.03°±7.75°矫正为12.88°±8.79°、17.9°±10.3°和8.85°±3.65°,手术前后有显著性差异(P<0.01),末次随访分别为:13.89°±9.36°、19.3°±5.4°和9.06°±3.78°,与术后比较无显著性差异(P>0.01)。顶椎椎体旋转由术前2.83°±1.25°矫正为1.37°±1.13°(P<0.01),末次随访(1.32°±1.04°)与术后比较无显著性差异(P>0.05);身高平均增长4.45 c...     

青少年特发性脊柱侧凸严重程度和弯型与SRS-22问卷评分的相关性分析

目的:探讨青少年特发性脊柱侧凸(adolescent idiopathic scoliosis,AIS)不同弯型及不同Cobb角与SRS-22问卷各维度评分的相关性。方法:对2010年6月~2011年7月在我科就诊且填写SRS-22简体中文版问卷的272例未经任何治疗的女性AIS患者进行回顾性分析。根据冠状面Cobb角将所有患者分为小Cobb角(20°~39°)和大Cobb角(40°~75°)两组,并根据弯型特征将每组患者分为单胸弯、单胸腰弯/腰弯、双胸弯、胸腰双弯四个亚组。对同一Cobb角组内不同弯型亚组间和不同Cobb角组间同一弯型患者的SRS-22问卷各维度评分差异均采用Kruskal-Wallis检验。结果:小Cobb角组单胸弯和单胸腰弯/腰弯患者的功能活动、自我形象、精神健康评分明显高于大Cobb角组的患者(P<0.05),双胸弯患者的功能活动评分和总分均显著优于大Cobb角组的患者(P<0.05)。在小Cobb角组中,单胸弯患者的功能活动评分显著高于单胸腰弯/腰弯和胸腰双弯患者(P<0.05);自我形象评分双胸弯患者明显低于单胸弯患者和单胸腰弯/腰弯患者(P<0.05)。在大Cobb角组中,胸腰双弯患者的疼痛评分明显低于单胸弯患者(P<0.05);自我形象评分双胸弯患者明显低于其他三种弯型患者(P<0.05)。结论:在轻中度女性AIS中,Cobb角大小及弯型特征对患者的SRS-22问卷评分会造成一定程度的影响,其中双胸弯对患者的自我形象评分的影响尤为明显。     

青少年特发性脊柱侧凸患者结束支具治疗后侧凸进展的危险因素分析

目的研究青少年特发性脊柱侧凸(adolescent idiopathic scoliosis,AIS)患者结束支具治疗后侧凸进展的危险因素,为AIS的科学、合理使用支具治疗提供理论依据。方法纳入2013-03-2016-03于我院支具治疗的164例青少年特发性脊柱侧凸患者,结束支具治疗后随访24个月,以侧凸Cobb进展≥5°诊断为支具治疗后侧凸进展,设为进展组,侧凸Cobb进展5°设为非进展组。调查两组患者初诊年龄、性别、初诊Cobb角等病历资料,通过Logistic回归分析探究AIS患者结束支具治疗后侧凸进展的独立危险因素。结果 AIS患者结束支具治疗后侧凸进展38例,进展率23.17%,平均侧凸Cobb角(6.84±0.87)°,未进展126例,平均侧凸Cobb角(3.77±0.65)°;两组初发Cobb角、顶椎旋转度、站高增长速度、女性初潮年龄、Risser征的差异有统计学意义(P0.05);Logistic回归分析证实:初发Cobb角≥35°、顶椎旋转度≥Ⅲ度、女性初潮年龄12岁、站高增长速度30 mm/年,均是AIS患者结束支具后侧凸进展的独立危险因素。结论 AIS患者结束支具治疗后侧凸进展发生率较高,初发Cobb角≥35°、顶椎旋转度≥Ⅲ度、站高增长速度30 mm/年、女性初潮年龄12岁均会增加侧凸进展风险。     

青少年特发性脊柱侧凸患者心脏异常的发生率

目的:研究青少年特发性脊柱侧凸(adolescent idiopathic scoliosis,AIS)患者心脏异常的发生率,探讨可能影响AIS患者心脏异常发生的相关因素.方法:2008年6月～2011年6月收治AIS患者719例,其中男113例,女606例,年龄10～18岁,平均15.1±2.2岁.术前均行心脏超声多普勒检查,统计AIS患者心脏异常的发生率.将心脏异常患者分为先天性心脏病及其他心脏异常2组,分别按性别(男组与女组)、弯型(胸弯组与腰弯/胸腰弯组)分组比较先天性心脏病发生率;分别按弯型(胸弯组与腰弯/胸腰弯组)、Cobb角(≤70°组与＞70°组)及胸椎后凸角(＜10°、10°～40°与＞40°组)分组比较其他心脏异常的发生率.利用二分类Logistic回归分析探讨AIS患者弯型(胸弯组与腰弯/胸腰弯组)、Cobb角(连续变量)及胸椎后凸角(连续变量)是否为其他心脏异常发生的显著相关因素.结果:AIS患者心脏异常发生率为6.68％(48/719),其中先天性心脏病发生率为4.59％(33/719),包括房间隔缺损2.50％(21/719)、室间隔缺损0.56％(4/719)、动脉导管未闭0.28％(2/719)、永存左上腔静脉0.28％(2/719)、法洛四联症0.14％(1/719)、二尖瓣狭窄0.14％(1/719)、单心房单心室0.14％(1/719)及房间隔膨出瘤0.14％(1/719);其他心脏异常的发生率为2.09％(15/719),其中二尖瓣脱垂1.11％(8/719)、肺动脉高压0.97％(7/719).48例存在心脏异常的AIS患者中,36例在入院前未获知存在心脏异常,其中3例(8.33％)入院后需先行心脏干预手术(2例行房间隔缺损修补术,1例行动脉导管未闭封堵术),二期行脊柱侧凸矫正手术:12例入院前已获知有心脏异常,其中10例为先天性心脏病,均在脊柱侧凸发现前已行心脏干预手术.AIS患者先天性心脏病的发生率,按性别、弯型分组组间比较均无显著性差异(P＞0.05);二尖瓣脱垂、肺动脉高压的发生率,按弯型、Cobb角以及胸椎后凸角分组组间比较均无显著性差异(P＞0.05).二分类Logistic回归分析显示,二尖瓣脱垂及肺动脉高压的发生与弯型、Cobb角及胸椎后凸角无显著相关性(P＞0.05).结论:AIS患者有较高的心脏异常发生率,部分心脏异常可能严重影响脊柱手术安全性,需要在脊柱矫形术前先行心脏干预手术.AIS患者脊柱矫形术前应常规行心脏超声多普勒检查以评估心脏情况.     

青少年特发性脊柱侧凸与神经源性脊柱侧凸患者椎体和椎间盘的楔形变及其临床意义

目的:观察青少年特发性脊柱侧凸(adolescent idiopathic scoliosis,AIS)与神经源性脊柱侧凸(neurological scoliosis,NS)患者的椎体和椎间盘的楔形变情况,探讨其临床意义。方法:对35例AIS患者和31例NS患者(继发于Chiari畸形)应用Cobb法测量胸椎和腰椎每个侧凸范围内顶椎及其上、下各两个椎体和相应椎间盘的楔变角,计算其占整个侧凸角度的百分比(楔变率),得出侧凸范围内5个椎体的平均楔变率和4个椎间盘的平均楔变率。应用SPSS10.0统计软件进行统计分析,组间比较采用单因素方差分析。结果:相同病因、相同侧凸部位、相同Cobb角分组情况下,椎体与椎间盘的楔变率存在显著性差异(P0.05)。相同病因、相同侧凸部位,Cobb角60°组的椎体楔变率和椎间盘楔变率与Cobb角≥60°组比较均无显著性差异(P0.05)。相同侧凸部位、相同Cobb角分组,AIS组椎体和椎间盘的楔变率分别与NS组比较均无显著性差异(P0.05)。结论:AIS与NS患者椎体与椎间盘的相对楔形变方式相同,AIS患者的椎体楔形变可能是继发的。在治疗脊柱侧凸时,即便是较小角度的脊柱侧凸,都应该考虑到其存在椎体和椎间盘的楔形变。     

行支具治疗的特发性脊柱侧凸患儿生长高峰期Cobb角进展速率变化及其对支具疗效的影响

目的:评估行支具治疗的特发性脊柱侧凸(idiopathic scoliosis,IS)患儿青春期生长高峰参数及生长高峰时的脊柱侧凸Cobb角进展速率(angle velocity,AV)变化情况,评估正性和负性AV组之间支具疗效的差异及不同支具疗效组之间生长参数的差异。方法:选取初诊时Y三角软骨未闭、以3~6个月为周期随访至停止支具治疗或因侧凸进展而行手术治疗的女性IS患儿35例。随访时测量的指标包括实足年龄、Y三角软骨闭合状态、Risser征、身高、脊柱长度、主弯Cobb角和尺桡骨远端骨龄(digital radius and ulnar,DRU)分级。根据纵向数据判定身高和脊柱生长速率峰值(peak height growth velocity,PHGV;peak spinal growth velocity,PSGV)及相应年龄,分析AV在该阶段的变化情况及其对支具疗效的影响。支具治疗失败定义为主弯Cobb角进展≥5°或进展至超过40°需行手术治疗。结果:35例患儿初诊年龄为10.2±1.5岁(8~12.5岁),初诊Cobb角为26.5°±5.0°(20°~38°),20例主胸弯或胸腰双弯患儿接受Milwaukee支具治疗,15例胸腰弯及腰弯患儿接受Boston支具治疗。随访时间为5.1±2.1年(4.0~6.2年),末次随访年龄15.3±2.2岁(12~18岁),末次随访Cobb角为34.0°±12.6°(9°~59°)。支具治疗成功15例(42.9%);支具治疗失败20例(57.1%),其中转为手术16例(45.7%)。支具治疗失败组患儿PHGV年龄、PSGV年龄均较治疗成功组患儿更小(P0.05),而支具治疗失败组的末次随访Cobb角、胸弯百分率及PSGV时AV均高于成功组(P0.05),PHGV和PSGV的值、初诊Cobb角两组之间无统计学差异(P0.05)。PSGV时负性AV组19例(54.3%),正性AV组16例(45.7%),负性AV组的支具治疗失败率、手术率、PSGV时AV及末次随访Cobb角均显著低于正性AV组(P0.05)。结论:行支具治疗的IS患儿生长高峰期时AV变化与支具疗效显著相关。处于生长加速期的IS患儿,其支具治疗失败率较高,尤其是脊柱生长高峰发生时间较早的胸弯型患儿。生长高峰时负性AV预示着更好的远期支具治疗效果。     

双胞胎青少年特发性脊柱侧凸的发病特点

目的 :观察青少年特发性脊柱侧凸(adolescent idiopathic scoliosis,AIS)双胞胎的共同发病率,比较同卵双胞胎之间的发病特点。方法:2007年1月~2016年12月期间我院收录同时患有AIS的双胞胎患者21对,其中女19对(含三胞胎1例),男2对,记录其初诊年龄、女性月经初潮年龄、BMI、Cobb角、胸椎后凸角、腰椎前凸角、Risser征等资料。通过短串联重复序列检测明确区分同卵双胞胎与异卵双胞胎,比较同卵双胞胎和异卵双胞胎的AIS共同发病率。选取同卵双胞胎中两人Cobb角差值≥10°的病例,将其中度数大者纳入侧凸较大组,度数小者纳入侧凸较小组,采用配对样本t检验比较两组之间初潮年龄、BMI、Risser征临床资料的差异。结果:21对双胞胎平均初诊年龄13.2±2.5岁,女性月经初潮年龄12.2±1.4岁,初诊时平均Cobb角29.2°±14.8°,胸椎后凸角16.8°±9.2°,腰椎前凸角45.5°±7.4°,BMI 17.0±1.6kg/m2,Risser征2.3±1.6。21对双胞胎中同卵双胞胎17对,异卵双胞胎4对。同卵双胞胎中16对(94.1%)共同患有AIS,11对(68.8%)弯型一致,4对(25.0%)Cobb角差值小于10°。异卵双胞胎中3对(75.0%)共同患有AIS,1对(33.3%)弯型一致,1对(33.3%)Cobb角差值小于10°。同卵双胞胎中Cobb角差值≥10°者12对,侧凸较大组的月经初潮年龄和BMI均小于侧凸较小组(P0.05),Risser征两组之间无统计学差异(P0.05)。结论 :同卵双胞胎AIS患者共同发病率较高(94.1%)且弯型一致,但同卵双胞胎两者间畸形严重程度不一,双胞胎中畸形较重者的月经初潮年龄较小、BMI较低。     

青少年特发性脊柱侧凸患者出生时父母年龄与其侧凸类型及严重程度的关系

目的:探讨青少年特发性脊柱侧凸(adolescent idiopathic scoliosis,AIS)患者出生时的父母年龄与AIS患者的侧凸类型、侧凸严重程度的关系.方法:选取来自华东地区初诊的AIS女性患者308例.年龄9.7～18.5岁,平均15.0岁.所有患者就诊时均记录患者性别、出生日期、初诊日期、侧凸节段、主弯Cobb角度数、分娩方式、胎位、是否早产及患者父母的出生日期.根据主弯Cobb角度数将所有患者分为3组,A组<20°;B组为20°～39°;C组≥40°;根据侧凸类型将患者分为6组,单胸弯组(Ⅰ组),双胸弯组(Ⅱ组),胸腰双主弯组(Ⅲ组),胸腰弯组(Ⅳ组),腰弯组(Ⅴ组),三弯组(Ⅵ组).结果:根据Cobb角分组后,A组(n=48)、B组(n=214)、C组(n=46)患者出生时的平均父亲年龄分别为27.35、26.7、27.0岁,平均母亲年龄分别为25.8、25.2、25.5岁,三组间均无统计学差异(P>0.05).根据患者侧凸类型分组后,Ⅰ组(n=72)、Ⅱ组(n=14)、Ⅲ组(n=127)、Ⅳ组(n=44)、Ⅴ组(n=30)、Ⅵ组(n=21)患者出生时的平均父亲年龄分别为27.0、26.6、26.5、27.7、27.0、27.0岁,各组平均母亲年龄分别为25.9、25.5、25.3、25.0、25.1、25.2岁,各组间无统计学差异(P>0.05).自然分娩组和剖腹产组平均Cobb角度数分别为29.7°和30.5°,胎位正常组和胎位异常组平均Cobb角度数分别为29.8°和29.9°.足月产组和早产组平均Cobb角度数分别为29.9°和29.5°,均无统计学差异(P>0.05).结论:AIS患者出生时的父母年龄与患者的侧凸类型及侧凸严重程度无显著相关性,提示AIS患者的侧凸类型及主弯Cobb角度数不受患者出生时的父母年龄的影响.     

哈尔滨市青少年脊柱侧凸普查与支具治疗结果分析

[目的]调查哈尔滨市青少年脊柱侧凸的患病率及类型,分析支具治疗的临床效果。[方法]于2005年10月～2009年10月对哈尔滨市城乡32所中、小学校6～16岁的24 362名中、小学生进行脊柱侧凸普查,统计患病率情况。根据特发性脊柱侧凸患者Cobb角大小不同,给予热塑支具治疗(Cobb角20°～40°)。每6个月复查1次,摄站立位全脊柱正侧位X线片,分析治疗结果。[结果]第一检结果阳性1 240名(5.09%),第二检阳性518名(2.13%),其中497名进行第三检,全脊柱正侧位X线片示Cobb角≥10°者423名,患病率为1.74%。特发性脊柱侧凸116例(Cobb角20°～40°)进行热塑支具治疗,支具治疗病例平均随访38个月,84例(72.4%)治疗有效,32例(27.6%)出现脊柱侧凸进展,治疗无效。Cobb角20°～30°组的矫正效果优于Cobb角30°～40°组,两组比较有显著差异(P<0.05)。[结论]通过普查,可以早发现、早诊断青少年脊柱侧凸,以便及时选择适当的方法进行治疗。热塑矫形支具治疗青少年特发性脊柱侧凸能够取得较好疗效,侧凸柔软性好,Cobb角较小,则矫正效果好。     

青少年特发性脊柱侧凸不同弯型患者椎体和椎间盘楔形变的差异及临床意义

目的:比较不同弯型、不同Cobb角的青少年特发性脊柱侧凸(adolescent idiopathic scoliosis,AIS)患者椎体和椎间盘楔形变及其对整体Cobb角构成的差异,探讨其临床意义。方法:2007年1月~2009年6月对收治的110例单弯型AIS患者按弯型分组,其中主胸弯39例(A组),胸腰弯33例(B组),主腰弯38例(C组)。每组根据侧凸Cobb角大小再分为<40°和≥40°两个亚组。分别测量每个主弯范围内所有椎体和椎间盘的楔形变角(楔变角),并分别计算椎体与椎间盘楔变角之和分别占整个主弯Cobb角的百分比(楔变角所占Cobb角比率)。结果:全部患者平均年龄13.6±1.9岁;平均Cobb角34.4°±10.5°;平均Risser征2.4±1.7。三组间平均年龄、Cobb角、Risser征均无显著性差异(P>0.05)。A组椎体楔变角及所占比率明显大于椎间盘(21.9°±5.6°比13.7±5.9°,62.3%比37.7%,P<0.001),B组与C组椎间盘楔变角及所占比率明显大于椎体(24.1°±9.2°比10.4°±3.8°,69.0%比31.0%,P<0.001;25.1°±7.2°比7.7°±2.4°,76.6%比23.4%,P<0.001)。各组内Cobb角≥40°患者的椎体与椎间盘楔变角均显著大于Cobb角<40°患者的楔变角(P<0.001)。随Cobb角增加,A组患者椎体楔变角占整体Cobb角比率仍然大于椎间盘,而B组和C组患者椎间盘楔变角占整体Cobb角比率仍然大于椎体。三组顶椎楔变角均与相应Cobb角大小成显著线性正相关(P<0.001)。结论:AIS各种弯型侧凸均存在不同程度的椎体与椎间盘楔形变。主胸弯Cobb角构成以椎体楔形变为主,胸腰弯和主腰弯则以椎间盘楔形变为主,提示不同弯型间可能存在不同的生物力学发生机制。     

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.     

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.     

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.     

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.     

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.     

Dilemma of Membrane Biocompatibility and Reuse

Abstract: Numerous articles have been published on the multiple use of dialyzers and on the effect of different reprocessing chemicals and techniques on the dialyzer biocompatibility and performance. The results often appear contradictory, especially those comparing standard biocompatibility parameters. Despite this confusion, a discerning review of the published works allows certain limited conclusions to be drawn. Reprocessing of used hemodialyzers changes the biocompatibility profile of a dialyzer as defined by the parameters complement activation. leukopenia, and cytokine release. The effect of reprocessing depends on the chemicals and reprocessing technique applied and also on the type of membrane polymer being subjected to the reprocessing procedure. Reports of pyrogenic reactions indicate that the flux of the membrane also influences how suitable it is for safe reuse. An increased risk of allergic and pyrogenic reactions appears to be associated with dialyzer reuse. Furthermore, there has been a lack of investigations into the immunologic effect of the layer of adsorbed and chemically altered proteins that remains on the inner surface of reprocessed dialyzers. We conclude that the clinical benefit of dialyzer reuse cannot be generally accepted from a biocompatibility point of view.     

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.