肢体远隔缺血预处理对肝脏手术中血清TNF-α和HMGB1水平的影响

目的探讨肢体远隔缺血预处理对肝脏手术中血清TNF-α和HMGB1水平的影响。方法 60例择期行肝部分切除手术的患者,ASAⅠ或Ⅱ级,随机分成两组:RIPC组(R组)接受右上肢缺血预处理,对照组(C组)不进行预处理。分别于肝脏缺血前10min(T_0)、再灌注后1h(T_1)、6h(T_2)、24h(T_3)、48h(T_4)经中心静脉导管采集血样测定TNF-α、高迁移率族蛋白B1(HMGB1)及谷草转氨酶(AST)、谷丙转氨酶(ALT)水平。结果与T_0比较,T_1~T_4时两组血清TNF-α、HMGB1及AST、ALT水平均明显升高(P0.05)。与C组比较,T_1~T_4时R组TNF-α、HMGB1及AST、ALT水平均明显降低(P0.05)。结论肢体远隔缺血预处理用于肝脏部分切除术中,能够减轻肝脏缺血-再灌注损伤程度,可能与缓解肝脏缺血-再灌注时血清TNF-α、HMGB1的释放,减轻全身炎症反应有关。     

呼气末正压通气对腹腔热灌注化疗患者呼吸力学及肺功能的影响

目的探讨不同呼气末正压通气对腹腔热灌注化疗患者呼吸力学及肺功能的影响。方法选择择期行腹膜癌热灌注化疗的患者90例,男55例,女35例,年龄40~70岁,ASAⅠ~Ⅲ级。随机分为三组,每组30例。A组为容量控制通气(VCV)组,VT10 ml/kg;B组为VCV+低PEEP组,VT6ml/kg,PEEP 5cm H_2O;C组为VCV+高PEEP组,VT6ml/kg,PEEP 10cm H_2O;术中调整RR维持PETCO2 35~45 mm Hg。于气管插管后5 min(T_1)、腹腔热灌注化疗开始前(T2)、化疗结束时(T_3)、气管拔管前(T4)记录气道峰压(Ppeak)、气道平台压(Pplat)和平均气道压(Pmean),计算动态肺顺应性(C_(dyn))。并取桡动脉血进行血气分析,计算氧合指数(OI)、呼吸指数(RI)、肺泡-动脉血氧分压差(A-aDO_2)及死腔率(VD/VT)。记录术后7d内肺部相关并发症情况。结果与A组比较,T_1~T_4时B、C组Ppeak、Pplat、A-aDO_2和RI明显降低,OI和VD/VT明显升高(P0.05);T_2~T_4时B、C组Pmean明显降低,Cdyn和PaO_2明显升高(P0.05)。与T_1比较,T_2~T_4时A组Ppeak、Pplat和Pmean明显升高,C_(dyn)明显降低(P0.05);T_3时B组Ppeak和Pplat明显升高(P0.05),T_2~T_4 Pmean明显升高(P0.05),T3、T4时C_(dyn)明显降低(P0.05);T_2~T_4时C组Ppeak、Pplat和Pmean明显升高(P0.05),T_3、T_4时Cdyn明显降低(P0.05)。与T0时比较,T2~T4时三组PaO_2和OI明显降低,A-aDO_2、RI和VD/VT明显升高(P0.05)。术后7d内B、C组肺部感染、低氧血症和肺不张的发生率明显低于A组(P0.05)。结论小潮气量(6ml/kg)联合PEEP(5cm H_2O)通气可以显著改善腹膜癌患者术中热灌注期间肺功能,降低围术期肺部并发症的发生风险。     

远隔肢体缺血预处理对腹主动脉瘤手术病人肺损伤的影响

目的 评价远隔肢体缺血预处理对腹主动脉瘤手术病人肺损伤的影响.方法 择期行肾下型腹主动脉瘤切除人工血管置换术病人62例,性别不限,年龄54～72岁,体重指数21 ～ 36kg/m2,ASA分级Ⅱ或Ⅲ级.采用随机数字表法,将病人随机分为2组(n=31):对照组(C组)和远隔肢体缺血预处理组(RLIP组).RLIP组在麻醉诱导后手术前将左上肢用袖带加压至200 mm Hg 5 min后袖带放气5 min,重复2次.分别于气管插管后10 min(T0)、主动脉开放后30 min(T1)、术后4 b(T2)、8h(T3)、12 h(T4)、24 h(T5)时采集动脉和静脉的血样,进行动脉血气分析,计算肺泡-动脉血氧分压差(PA-aaO2)和呼吸指数(RI),并测定静脉血血清白细胞介素-6(IL-6)、肿瘤坏死因子-α(TNF-α)浓度、血浆超氧化物歧化酶(SOD)活性和丙二醛(MDA)浓度.分别于上述时点记录气道峰压(Ppeak)、气道平台压(Pplat)和呼气末正压(PEEP),以计算肺动态顺应性(Cs)和肺静态顺应性(Cd).记录术后低氧血症发生情况、拔除气管导管时间和ICU停留时间.结果 与C组比较,RLIP组PA-aO2、RI和血IL-6、TNF-α和MDA的浓度降低,Cs、Cd和血SOD活性升高,术后低氧血症发生率降低,ICU停留时间和拔除气管导管时间缩短(P＜0.05).结论 远隔肢体缺血预处理可减轻腹主动脉瘤手术病人肺损伤,其机制与抑制炎性反应及脂质过氧化反应有关.     

甲基强的松龙对肺叶切除术患者单肺通气时肺功能和炎症反应的影响

目的探讨甲基强的松龙(甲强龙)对肺叶切除术患者单肺通气时肺功能和炎症反应的影响。方法选择择期拟行肺叶切除术患者60例,男46例,女14例,年龄18~60岁,ASAⅠ或Ⅱ级,采用随机数字表法分为两组:甲强龙组(M组)和对照组(C组),每组30例。M组于麻醉诱导前30min静脉注射甲强龙2mg/kg,C组于相同时点静脉注射等量生理盐水。分别记录单肺通气前(T_0)、单肺通气30min(T_1)、单肺通气1h(T_2)、恢复双肺通气10min(T_3)及术毕(T_4)时的MAP、气道峰压(Ppeak)、气道平台压(Pplat)及动态肺顺应性(Cdyn),并于上述时间点抽取桡动脉血行血气分析,检测PaO_2和PaCO_2,计算氧合指数(OI)、肺泡-动脉血氧分压差(A-aDO_2)及呼吸指数(RI)。分别于T_0、T_4、术后6h(T_5)及术后24h(T_6)采集中心静脉血样,采用ELISA法检测血清TNF-α、IL-6及IL-10的浓度。记录术后72h肺部并发症的发生情况。结果与T_0时比较,T_1、T_2时两组MAP、Cdyn明显降低,Ppeak、Pplat明显升高(P0.05);T_1~T_4时OI明显降低,A-aO_2、RI明显升高(P0.05);T_4~T_6时血清TNF-α、IL-6及IL-10浓度明显升高(P0.05)。与C组比较,T_1、T_2时M组Ppeak、Pplat明显降低,Cdyn明显升高(P0.05);T_4~T_6时M组血清TNF-α、IL-6浓度明显降低,IL-10浓度明显升高(P0.05)。两组患者术后72h肺部并发症发生率差异无统计学意义。结论甲强龙可有效改善肺叶切除术患者单肺通气时动态肺顺应性,优化呼吸动力学,减轻机体炎症反应,但对肺氧合及换气功能无明显影响。     

个体化呼气末正压对心肺转流下瓣膜手术患者肺功能的影响

目的探讨心脏瓣膜术中早期应用个体化呼气末正压(PEEP)对患者肺功能的影响。方法选择2019年7—10月择期行瓣膜手术的患者33例,男11例,女22例,年龄40～70岁,BMI 18～26 kg/m~2,ASAⅡ或Ⅲ级,心功能Ⅱ或Ⅲ级。采用随机数字表法将患者分为两组:对照组(C组,n=17)和个体化PEEP组(P组,n=16),两组术中麻醉维持为全凭静脉麻醉。停机后P组采用阶梯PEEP法滴定适宜的PEEP,并维持至手术结束,C组设置固定PEEP 4 cmH_2O。记录手术前(T_0)、肺复张前(T_1)、肺复张后40 min(T_2)、术后2 h(T_3)、术后24 h(T_4)的氧合指数(PaO_2/FiO_2),T_0—T_2时的HR、MAP、CVP,T_1—T_3时的肺动态顺应性(Cdyn)。使用经胸超声检查并记录T_0、T_2—T_4时的肺超声评分(LUS评分)和术后肺部并发症的发生情况。结果与T_1时比较,T_2、T_3时P组PaO_2/FiO_2和Cdyn明显升高(P0.05)。与C组比较,T_2时P组PaO_2/FiO_2和Cdyn均明显升高(P0.05),T_2—T_4时P组LUS评分明显降低(P0.05),P组术后肺水肿的发生率明显降低(P0.05)。两组其余术后肺部并发症发生率差异无统计学意义。结论在心脏瓣膜手术心肺转流停机后早期应用个体化PEEP具有肺保护作用。     

肺超声评分评价肺保护性通气策略对老年开腹手术患者肺损伤的影响

目的通过肺超声评分探讨肺保护性通气策略减轻老年开腹手术患者肺损伤的作用。方法选择2019年8月至2020年6月择期开腹手术患者50例,男33例,女17例,年龄65～80岁,BMI 18～25 kg/m~2,ASAⅠ—Ⅲ级。采用随机数字表法将患者分为两组:对照组(C组)和肺保护性通气组(P组),每组25例。所有患者常规麻醉诱导,采用容量控制的通气模式。C组设置V_T 8 ml/kg,不使用呼气末正压(PEEP);P组设置V_T 6 ml/kg, PEEP 6 cmH_2O,每间隔30 min给予手法肺复张。采用床旁超声评估患者双侧共12个区域的肺部超声,各区域分数累积为肺超声评分(LUS)。记录入室时(T_0)、麻醉诱导气管插管后5 min(T_1)、手术开始后2 h(T_2)、手术结束时(T_3)、气管导管拔除后15 min(T_4)、2 h(T_5)、术后1 d(T_6)的LUS评分、HR、MAP、SpO_2、PaO_2和PaCO_2。记录T_1—T_3时的氧合指数(PaO_2/FiO_2)、气道峰压(Ppeak)、吸气末平台压(Pplat)和驱动压力(ΔP)。记录术后7 d内肺部并发症(PPCs)的发生情况。结果与T_0时比较,T_1—T_5时C组和P组LUS评分明显升高(P0.05)。与T_1时比较,T_2—T_3时C组PaO_2/FiO_2明显降低(P0.05),P组ΔP明显降低(P0.05)。与C组比较,P组T_2—T_5时LUS评分明显降低(P0.05),T_2—T_3时PaO_2/FiO_2明显升高(P0.05)、ΔP明显降低(P0.05)。C组术后7 d内PPCs发生率为20%,P组未发生PPCs(P0.05)。结论床旁肺超声监测下,老年开腹手术患者在全麻期间和术后早期LUS评分升高,肺通气丢失。肺保护性通气策略可降低患者围术期的肺超声评分,减少肺通气损失,降低术后7 d的肺部并发症发生率。     

压力控制容量保证通气模式对肺切除术患者术后肺部并发症的影响

目的观察压力控制容量保证(PCV-VG)通气模式对肺切除术患者术后肺部并发症(PPCs)的影响。方法选择择期全麻下行胸腔镜肺切除术患者42例,男19例,女23例,年龄18～65岁,ASAⅠ或Ⅱ级。将患者随机分为两组:自双肺通气开始至手术结束始终使用PCV-VG模式通气组(P组)和始终使用容量控制通气(VCV)模式通气组(V组),每组21例。P组双肺通气期间V_T 8 ml/kg,单肺通气(OLV)期间V_T 6 ml/kg,压力上升时间设置为0.5 s; V组双肺通气期间设置V_T 8 ml/kg, OLV期间设置V_T 6 ml/kg,吸气暂停时间为0 s。记录术后1、2、3 d和出院前PPCs的发生情况。记录OLV前(T_0)、OLV 30 min(T_1)、OLV 60 min(T_2)和OLV结束后(T_3)的吸气峰压(PIP)、驱动压(ΔP)、动态肺顺应性(Cdyn)以及PaO_2、PaCO_2和氧合指数(PaO_2/FiO_2)。结果术后1 d P组PPCs发生率明显低于V组[2例(9%) vs 8例(38%),P0.05]。术后2、3 d和出院前两组PPCs发生率差异无统计学意义。T_0—T_3时P组PIP明显低于V组(P0.05)。与T_0时比较,T_1、T_2时两组PIP和ΔP明显升高(P0.05),Cdyn明显降低(P0.05)。T_0—T_3时两组ΔP、Cdyn、PaO_2、PaCO_2和PaO_2/FiO_2差异无统计学意义。结论 PCV-VG模式优于VCV模式,可明显减少肺切除患者术后1 d肺部并发症的发生,降低术中吸气峰压。     

远隔缺血时处理对体外循环心脏瓣膜置换术患者全身炎性反应的影响

目的 评价远隔缺血时处理对体外循环(CPB)心脏瓣膜置换术患者全身炎性反应的影响.方法 择期CPB心脏瓣膜置换术患者40例,年龄40～64岁,体重50～70 kg,ASA分级Ⅱ或Ⅲ级,采用随机数字表法,将其分为2组(n=20):对照组(C组)、远隔缺血时处理组(R组).R组于主动脉阻断后对右下肢实施3周期5 min缺血/5 min再灌注处理.于CPB前即刻、CPB结束后即刻、6、24h(T1-4)时取右颈内静脉血样,检测血清细胞间粘附分子-1 (ICAM-1)、白细胞介素-6(IL-6)、肿瘤坏死因子-α(TNF-α)的浓度.结果 与C组比较,R组血清ICAM-1、IL-6、TNF-α浓度降低(P＜0.05).与T1时比较,两组T2.3时血清ICAM-1、IL-6、TNF-α浓度升高,C组T4时血清ICAM-1、IL-6浓度升高,R组T4时血清IL-6浓度升高(P＜0.05);与T2时比较,两组T3.4时血清ICAM-1、IL-6、TNF-α浓度降低(P＜0.05);与T3时比较,两组T4时血清ICAM-1、IL-6、TNF-α浓度降低(P＜0.05).结论 远隔缺血时处理可减轻CPB心脏瓣膜置换术患者全身炎性反应.     

远隔缺血预处理联合后处理对体外循环下心脏瓣膜置换术患者术后谵妄的影响

目的探讨远隔缺血预处理联合后处理(RIPC+RIPostC)对体外循环(CPB)下心脏瓣膜置换术患者术后谵妄(POD)的影响。方法招募于本院手术室接受择期CPB下心脏瓣膜置换术的患者80例, 年龄44～64岁, 依据随机数字表法将其分成对照组(C组)和处理组(R组), 每组40例。R组患者于CPB开始前30 min实施RIPC, 并于CPB结束前30 min实施RIPostC。具体处理措施:患者下肢绑好充气式袖带, 充气加压直至压力为200 mmHg(1 mmHg=0.133 kPa), 保持5 min, 随后袖带完全放气直至压力为0;5 min后再次充气加压, 如此进行3个循环;C组将袖带绑于患者下肢, 但不进行充气及放气操作。分别于术前1天及术后第1、3天时抽取外周静脉血并测定血常规。术后3天内采用重症监护室(ICU)意识障碍评估法(CAM-ICU)进行POD的评估。神经认知测试在术前、出院时和术后3个月进行, 术后认知功能障碍(POCD)和痴呆症(AD)的评估采用简易精神状态检查量表(MMSE), 并排除术前<24分的患者。记录术中及术后任何不良事件包括窦性心动过缓或低血压...     

肺保护性通气策略对腹腔镜胃癌根治手术老年患者肺氧合功能及术后肺部并发症的影响

目的探讨肺保护性通气策略(lung protective ventilation strategy,LPVS)对腹腔镜胃癌根治手术老年患者肺氧合功能及术后肺部并发症(postoperative pulmonary complications,PPCs)的影响。方法选择接受腹腔镜胃癌根治手术的老年患者115例,男69例,女46例,年龄≥65岁,ASAⅠ—Ⅲ级,随机分为两组:常规容量控制通气组(CV组,n=57)和肺保护性通气组(PV组,n=58)。记录插管后10 min(T_1)、气腹后10 min(T_2)、气腹后60 min(T_3)、气腹结束10 min(T_4)时的气道峰压(Ppeak),计算肺顺应性(Cdyn),并在T_1—T_4时抽取动脉血进行血气分析,计算氧合指数(OI)、肺泡动脉血氧分压差(A-aDO_2);记录术后第2天改良肺部感染评分(mCPIS);记录术后7 d内PPCs发生情况。结果与T_1时比较,T_2时两组Cdyn均明显降低(P0.05);T_3—T_4时PV组Cdyn明显高于CV组(P0.05);T_3—T_4时PV组OI明显高于CV组、A-aDO_2明显低于CV组(P0.05)。术后第2天PV组mCPIS明显低于CV组(P0.05)。术后7 d内PV组PPCs发生率明显低于CV组(P0.05)。结论肺保护性通气策略能明显改善老年腹腔镜胃癌根治手术老年患者的肺氧合功能,降低术后肺部并发症,具有一定的肺保护作用。     

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.     

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.     

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.     

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.     

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.