经Delta通道椎间孔镜治疗神经根型颈椎病

目的:探讨经Delta通道椎间孔镜治疗神经根型颈椎病的早期临床疗效及安全性。方法:对2017年9月至2018年7月收治的10例神经根型颈椎病患者行经Delta通道后路椎间孔镜下椎间盘摘除术,其中男6例,女4例;年龄30～62(41.5±4.3)岁;均为单侧根性症状,其中C_(4,5) 2例,C_(5,6) 5例,C_(6,7) 3例。所有患者CT及MRI检查提示无后纵韧带骨化及黄韧带钙化等影像学表现,颈椎动力位X线片无颈椎不稳,经系统非手术治疗6周以上,疗效欠佳。观察患者术前及末次随访时颈肩痛VAS评分、JOA评分、NDI评分、颈椎生理曲度、颈椎病变节段椎间高度和稳定性的改变。结果:所有手术顺利完成,无脊髓、神经根或大血管损伤情况的发生。手术时间70～120 min,平均90 min;术中出血量30～90 ml,平均40 ml。10例患者均获得随访,时间6～14个月,平均9个月。所有患者术后神经根性疼痛缓解满意,神经功能有所改善。VAS评分由术前的7.15±2.01降至末次随访时的1.59±0.83;JOA评分由术前的12.57±1.24升至末次随访时的16.42±0.58;NDI评分由术前的41.82±4.71提高到末次随访时的9.59±3.52;末次随访与术前比较差异均有统计学意义(P0.05)。颈椎生理曲度D值由术前的(8.21±0.84) mm升至末次随访时的(10.89±0.96) mm (P0.05)。病变节段椎间高度术前、末次随访时分别为(5.62±0.59)、(5.60±0.57) mm,差异无统计学意义(P0.05)。末次随访时颈椎动力位X线片未见颈椎失稳。结论:经Delta通道后路椎间孔镜下椎间盘摘除术治疗神经根型颈椎病能取得较为满意的疗效,且不影响颈椎的稳定性,安全性可靠,值得临床应用。     

一种新型植骨重建钛网的初步临床应用

目的评价新型植骨重建钛网在颈前路椎体次全切除减压植骨融合术中的临床应用及疗效。方法采用颈前路椎体次全切除减压、新型钛网植骨融合术治疗颈椎退行性疾病患者53例,其中男38例,女15例,年龄39～76岁,平均49.7岁。手术方式包括单节段椎体次全切除22例,单节段椎体次全切除联合椎间盘切除减压28例,双节段椎体次全切除3例。术后定期随访颈椎X线片,比较术后椎间高度及颈椎生理曲度变化。采用日本骨科学会的JOA评分系统进行神经功能评价。结果单节段手术患者椎间高度从术前22.3mm±0.8mm增加至术后24.5mm±0.6mm,双节段手术患者椎间高度从术前平均42.3mm增加至术后平均45.7mm,6个月随访两者均无明显丢失。单节段手术患者颈椎曲度从术前8.2°±1.4°增加至术后14.5°±1.6°,但双节段手术患者颈椎曲度术前平均6.3°,术后平均仅为7.0°,6个月随访两者均无明显丢失。全部患者临床神经功能均有改善,JOA评分从术前8.4±0.5分提高至术后12.2±0.4分,6个月随访提高至14.5±0.3分。结论新型钛网的外形设计更符合颈椎椎体终板形态学特点,可有效避免术后钛网沉陷,临床应用单节段手术能够较好的重建颈椎椎间高度和生理曲度,而双节段手术由于该新型钛网设计的不足之处对于颈椎生理曲度的重建作用有限,有待进一步改进。     

Bryan颈椎人工椎间盘置换术后10年随访结果

目的 :观察Bryan颈椎人工椎间盘置换术后10年随访结果和并发症。方法:纳入在我院骨科行Bryan颈椎人工椎间盘置换术且获得长期随访、临床和影像学资料均完整的60例患者,其中神经根型颈椎病15例,脊髓型颈椎病41例,混合型颈椎病(脊髓型+神经根型)4例。47例患者为单节段置换,12例为双节段置换,1例为3节段置换。随访时间为124.0±8.3个月(117～150个月)。采用mJOA评分和VAS评分分别评估脊髓型颈椎病和神经根型颈椎病临床疗效,分析二次手术的原因和二次手术方案;颈椎屈伸位X线片评估末次随访时节段活动度情况,采用McAfee异位骨化分级观察末次随访时异位骨化情况。结果:脊髓型颈椎病患者术前mJOA评分为13.4±2.2分,末次随访时为15.8±1.1分(P0.05)。神经根型颈椎病患者术前上肢VAS评分为5.7±2.2分,末次随访时为0.7±0.9分(P0.05);术前颈痛VAS评分为4.7±2.2分,末次随访时为1.0±1.0分(P0.05)。混合型颈椎病患者术前m JOA评分为13.3±3.6分,末次随访时为15.4±1.1分;术前上肢VAS评分为4.3±2.6分,末次随访时为1.0±1.4分;术前颈痛VAS评分为2.8±1.5分,末次随访时为2.5±1.9分。7例患者接受了二次手术治疗,其中6例为手术节段异位骨化(包括初次手术单节段椎间盘置换术5例,双节段置换术1例;二次手术时3个节段异位骨化分级为Ⅲ级,4个节段为Ⅳ级)导致的新症状而行手术节段二次手术,1例为邻椎病行后路单开门椎管扩大成形术。74个手术节段的术前活动度为7.0°±2.9°,末次随访时活动度为4.6°±4.1°(P0.05)。末次随访时74个手术节段中有53个节段出现异位骨化,根据Mc Afee异位骨化分级,其中5个节段为Ⅱ级,21个节段为Ⅲ级,27个节段为Ⅳ级。结论:Bryan颈椎人工椎间盘置换术后随访10年取得了较好的疗效,但异位骨化的发生率较高,降低了手术节段的活动度,严重的异位骨化会导致手术节段出现新的神经症状而被迫行二次手术。     

人工颈椎间盘置换的近期临床疗效和影像学分析

目的分析人工颈椎间盘置换治疗神经根型颈椎病的临床疗效和影像学改变。方法回顾2012年9月至2014年3月收治的行单节段人工颈椎间盘置换术的神经根型颈椎病患者30例,其中获得完整随访资料的21例,于术前及术后7 d、1个月、3个月、6个月行临床评估和影像学数据采集。使用Odom评级、疼痛视觉模拟评分(visual analogue scale,VAS)、日本骨科协会(Japanese orthopaedic association,JOA)评分及颈椎功能障碍指数(neck disability index,NDI)评分评估临床疗效及神经功能的改善情况,通过颈椎正侧位、动力位X线片观察颈椎整体、置换节段脊柱功能单位的曲度及活动度,以及置换节段相邻节段的活动度。结果 21例患者获得完整随访,随访时间6~9个月,平均6.8个月。NDI评分自术前(40±8.4)分下降到末次随访的(12±7.3)分(P0.05),JOA评分由术前(9±3.2)分提高到末次随访的(13.6±3.0)分(P0.05),上肢疼痛VAS评分由术前(7.6±1.6)分下降至末次随访(1.8±0.4)分(P0.05)。术后3个月颈椎曲度、置换功能节段曲度、颈椎活动度及置换功能节段的活动度较术前明显改善。术后3、6个月邻近节段活动度无明显改变。结论人工颈椎间盘假体行椎间盘置换术临床效果可靠,影像学资料显示术后可改善颈椎整体及置换节段曲度和活动度,保留临近节段活动度。     

颈后路扩张通道下钥匙孔减压术治疗神经根型颈椎病

[目的]探讨颈椎后路可扩张通道下钥匙孔开窗减压髓核摘除术治疗神经根型颈椎病(cervical spondylotic radiculopathy,CSR)的临床疗效。[方法]2013年6月~2014年5月采用颈后路可扩张通道下钥匙孔开窗减压髓核摘除术治疗神经根型颈椎病患者8例,其中男3例,女5例;年龄32~58岁,平均42.3岁;C4、52例,C5、64例,C6、72例;对治疗前和术后3 d,术后3、6个月及末次随访时疼痛VAS评分、JOA评分、椎间隙高度、颈椎曲度进行统计学研究,并对术后随访期间的颈椎稳定性进行记录。[结果]8例患者均获得随访,随访时间8~19个月,平均14个月;手术时间40~80 min,平均56 min;术中出血量40~210 ml,平均86 ml;术后住院时间3~11 d,平均6.5 d;术后3 d,术后3、6个月及末次随访时疼痛VAS评分分别为:(3.23±0.21)分、(2.13±0.12)分、(2.23±0.18)分、(1.89±0.12)分与术前(7.23±1.22)分相比差异均有统计学意义(P0.05);术后3 d,术后3、6个月及末次随访时JOA评分分别为:(15.63±1.35)分、(16.21±1.23)分、(16.11±1.25)分及(15.89±1.28)分与术前(12.31±1.05)分相比差异均有统计学意义(P0.05),末次随访时优良率100%;颈椎生理区度C值从术前(7.56±0.99)mm提高到末次随访时(10.99±1.65)mm,差异有统计学意义(P0.05);术前和末次随访时病变节段椎间高度分别为(5.26±0.32)mm和(5.33±0.28)mm,差异无统计学意义(P0.05);过伸过屈位X线片未见明显颈椎失稳。术后伤口感染1例,经扩创、应用抗生素后伤口甲级愈合,无其他并发症。[结论]颈椎后路可扩张通道下钥匙孔开窗减压髓核摘除术治疗神经根型颈椎病短期内可取得较满意的临床疗效。     

ZERO-P钢板在单节段脊髓型颈椎病的临床疗效分析

目的探讨ZERO-P钢板应用于单节段脊髓型颈椎病(CSM)治疗的手术特点和近期临床疗效。方法 23例脊髓型颈椎病患者采用颈椎前路椎间盘髓核摘除、减压、零切迹钢板固定并椎间融合术,分析手术过程特点,对比手术前后、末次随访的吞咽情况,临床疗效(VAS和JOA评分)及术后融合节段椎间隙高度、Cobb氏角变化,判断椎间稳定情况及椎间融合率。结果手术时间85.8±26.6 min;术中失血83.7±32.7 mL。术后吞咽困难发生率13%。术后随访12月,23例患者术前颈及上肢VAS评分分别为3.2±1.5分、6.5±1.6分,JOA评分9.4±1.9分,末次随访颈及上肢VAS评分2.8±1.6分,1.2±0.7分,JOA评分14.8±1.9分,JOA评分术后改善率:优20例,良3例,优良率100%。术后1周和末次随访与术前相比融合节段椎间隙高度和Cobb氏角度明显改善(P0.001),术后1周与末次随访比较无明显间隙高度和角度丢失(P0.05),随访过程中未发现内固定螺钉松动、移位,末次随访颈椎动力位片判断椎间稳定率100%。结论 ZERO-P钢板单独应用于单节段脊髓型颈椎病的治疗的手术创伤小,操作简单,并发症低,并可有效改善和维持颈椎的病变节段生理曲度和间隙高度,临床近期疗效满意。     

前路颈椎桥形锁定融合器在颈椎间盘切除融合术治疗退变性颈椎病中的应用

目的评价退变性颈椎病行前路颈椎间盘切除融合术(anterior cervical discectomy and fusion,ACDF)中应用前路颈椎桥形锁定融合器的临床疗效。方法回顾性分析自2013年10月至2016年9月,我科应用前路颈椎桥形锁定融合器对104例退变性颈椎病患者行前路椎间减压ROI-C融合固定术,共植入108枚ROI-C。神经根型颈椎病48例,脊髓型颈椎病56例。术后3d、3个月、6个月、12个月定期随访并复查X线片或CT,用JOA、VAS评分评价末次随访时神经功能及疼痛改善情况,记录手术时间、出血量和并发症情况,根据末次随访时颈椎X线片或CT评价椎间隙高度和ROI-C椎间融合情况。结果本组104例患者均获随访,随访时间(18.41±7.39)个月,平均8～30个月;手术平均时间:单节段(51.30±2.17)min,双节段(105.53±7.14)min;平均出血量:单节段(43.72±2.63)mL,双节段(71.57±4.20)mL。神经根型颈椎病:末次随访时日本骨科协会(Japanese orthopaedic association,JOA)、视觉模拟评分(visual analogue scale,VAS)及椎间隙高度平均为(16.79±0.95)分、(2.36±0.90)分及(6.76±1.11)mm,与术前的(14.53±1.02)分、(7.70±1.60)分及(3.94±0.78)mm比较,差异有统计学意义(P0.001);脊髓型颈椎病:末次随访时JOA、VAS评分及椎间隙高度平均为(14.21±1.82)分、(1.44±0.79)分及(6.50±1.13)mm,与术前的(10.18±1.62)分、(3.53±1.46)分及(3.71±0.80)mm比较,差异有统计学意义(P0.001)。末次随访时104例均获骨性融合,平均融合时间:单节段(4.20±1.53)个月,双节段(5.41±6.15)个月。本组病例未出现喉返神经损伤、脑脊液漏、脊髓损伤、吞咽困难等并发症,随访期间均未发生感染、ROI-C松动移位或下沉等。结论退变性颈椎病行ACDF应用ROI-C能有效重建病变椎间隙高度,获得可靠的颈椎稳定性及椎间融合率,且手术时间短、术中出血少,术后并发症低,术后神经功能及疼痛改善显著,因此颈椎病行ACDF中单独应用ROI-C安全、有效,可获得满意的临床疗效。     

自锁式椎间融合器在一期后前路联合手术治疗脊髓型颈椎病中的应用(2年随访)

[目的]分析一期颈椎后路单开门椎管成型、前路椎间减压、自锁式椎间融合器自体植骨椎间融合术治疗脊髓型颈椎病的疗效.[方法]2006年9月～ 2008年4月,采用一期颈椎后路单开门椎管成型、前路椎间减压、自锁式椎间融合器自体植骨椎间融合术连续治疗脊髓型颈椎病52例;前路椎间减压单节段23例、双节段29例.记录患者术前及术后的JOA评分,在颈椎侧位X线片上测量椎间隙高度、椎间前凸角、颈椎前凸角的变化.[结果] 52例共随访24～40个月(平均30个月).52例患者在术后2周内均感到神经症状明显好转;没有发生手术相关并发症.术后6个月随访时,所有患者主诉四肢感觉、肌力、活动均较前明显改善,颈椎X线检查可见椎间已融合,椎间高度及生理曲度完好,无融合器移位、下沉、断裂发生.平均JOA评分由术前(7.3±0.5)分,提高到术后6个月(14.1±0.7)分,术后12个月(14.7±0.6)分,术后24个月(14.9±1.2)分;术后6个月随访时的JOA评分改善率:优21例,良25例,可6例,术后12个月及术后24个月时的JOA评分改善率与术后6个月无明显改变.[结论]采用一期颈椎后路单开门椎管成型、前路椎间减压、自锁式椎间融合器自体植骨椎间融合术治疗脊髓型颈椎病能获得颈髓前后方的充分减压及满意的临床疗效,能获得满意的颈椎曲度、稳定性重建及椎间融合.     

颈椎前路椎间盘切除融合术和后路单开门椎板成形术治疗多节段脊髓型颈椎病的早期并发症对比

目的对比颈椎前路椎间盘切除融合术(ACDF)和后路单开门椎板成形术治疗多节段脊髓型颈椎病(CSM)的早期并发症。方法 2010年1月—2014年12月收治多节段CSM患者236例,111例采用ACDF治疗(前路组)、125例采用颈椎后路单开门椎板成形术治疗(后路组)。记录患者术前和末次随访时颈椎曲度、日本骨科学会(JOA)评分以及术后3个月内并发症发生情况。结果末次随访时前路组颈椎曲度(14.8°±4.1°)优于后路组(9.5°±2.8°),差异有统计学意义(P 0.05);前路组末次随访时JOA评分和JOA评分改善率[(14.6±1.2)分、(75.6±3.5)%]均优于后路组[(13.2±2.0)分、(62.7±5.6)%],差异均有统计学意义(P 0.05)。14例患者术后早期发生并发症,发生率为5.93%,其中前路组5例(4.50%,5/111),后路组9例(7.20%,9/125)。最常见的并发症为喉上/喉返神经损伤(5例,前路组),最严重的并发症为脊髓损伤(3例,后路组),其余为C5神经根麻痹(2例)、脑脊液漏(2例)、切口愈合不良(1例)、切口血肿(1例),均为后路组病例。无食管、气管瘘及死亡患者。结论 ACDF和后路单开门椎板成形术治疗多节段CSM均可获得满意的临床疗效,ACDF能获得更好的颈椎曲度和神经功能,且并发症发生率较低。     

零切迹自稳型颈椎融合器(ROI-C)在颈椎前路减压融合术中的安全性与有效性评价

目的:评价颈椎前路椎间减压融合术中应用零切迹自稳型颈椎融合器(ROI-C)的安全性及临床疗效。方法:回顾性分析我院自2012年3月~2014年3月行颈椎前路椎间减压及ROI-C植骨融合的105例手术患者,其中男性76例,女性29例,年龄平均53.64±11.13岁(20~77岁);单节段76例,双节段23例,三节段5例,四节段1例,共置入ROI-C融合器141枚。记录手术时间、出血量和术后患者吞咽不适的发生率,采用VAS、JOA、NDI评价临床疗效,并利用影像学资料测量术前、术后颈椎曲度和融合节段椎间高度的变化。结果:105例患者均获得随访,随访时间平均22.80±7.04个月(12~36个月)。平均手术时间138.34±38.14min,平均手术出血量40.76±96.72ml。术前VAS评分为4.22±0.85分,术后6个月为1.48±0.62分,末次随访时为1.02±0.64分,与术前相比均具有统计学差异(P0.01)。术前JOA评分为9.84±2.02分,术后6个月为14.2±71.81分,末次随访时为14.83±1.61分,与术前相比差异有统计学意义(P0.01)。术前NDI评分为39.74±3.69分,术后6个月为12.71±2.82分,末次随访时为10.84±2.14分,均较术前明显改善(P0.01)。术前颈椎曲度平均为13.58°±7.51°,术后6个月为18.59°±7.11°,末次随访时为19.05°±6.95°,与术前相比有显著性差异(P0.01)。术前椎间隙高度为3.19±0.41mm,术后6个月为5.03±1.11mm,末次随访时为4.62±0.88mm,与术前相比差异有统计学意义(P0.05)。末次随访时所有患者均获得良好的骨性融合。术后早期患者吞咽不适和声音沙哑的发生率分别为4.76%(5/105)和7.62%(8/105),术后6个月上述症状均消失。本组患者随访期间均未发生术后伤口血肿或感染、内置物松动、移位或断裂等并发症。结论:颈椎前路椎间减压融合术中应用零切迹自稳型颈椎融合器(ROIC)安全、有效,可以获得满意的早期临床疗效,并且改善和维持颈椎整体曲度和椎间隙高度,减少患者术后吞咽不适和声音嘶哑情况的发生。     

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.