FloTrac/Vigileo系统用于单肺通气血流动力学的监测

目的探讨Flo Trac/Vigileo系统在单肺通气患者术中血流动力学监测的可行性。方法选取全麻胸腔镜下肺叶切除术患者25例,年龄35~65岁,ASAⅠ或Ⅱ级,术前无Flo Trac/Vigileo系统及经食管超声心动图(TEE)应用禁忌证。入室行桡动脉穿刺置管,连接Flo Trac/Vigileo系统,并于全麻诱导后置入TEE探头。分别同时采用Flo Trac/Vigileo系统与TEE监测并记录侧卧翻身后(开胸前,T0)、开胸单肺通气即刻(T1)、单肺通气15 min(T2)、单肺通气30 min(T3)、单肺通气45min(T4)、单肺通气60 min(T5)的SV、CO、SVV(Flo Trac/Vigileo系统)或c IVC(TEE监测)。其中由Flo Trac/Vigileo系统所测的SV和CO等记作SVF、COF;由TEE所测的记作SVT、COT。结果 T0~T5时SVF和SVT差异无统计学意义;整体相关性分析,相关系数r=0.84,P0.01。T0~T5时COF和COT差异无统计学意义;整体相关性分析,相关系数r=0.92,P0.01。SVV和的c IVC整体相关性分析,结果呈正相关,相关系数r=0.80,P0.01。结论 Flo Trac/Vigileo系统可在胸科手术中作为术中血流动力学的监测方法。     

肺叶切除术患者不同通气模式下每搏量变异度的变化

目的 探讨肺叶切除术患者不同通气模式下每搏量变异度(SW)的变化.方法 择期行肺叶切除术患者44例,年龄44～64岁,体重47～86 kg,ASA分级Ⅰ或Ⅱ级.采用FloTrac压力换能器及Vigileo心输出量监测仪持续监测CI、每搏量指数(SVI)和SVV.术中补液速率6～8 ml·kg-1·h-1(晶胶比1∶1)维持血容量.于仰卧位双肺通气5 min(T1)、侧卧位双肺通气2 min(T2)、单肺通气开胸前(T3)、单肺通气开胸后5 min(T4)、30 min(T5)、单肺通气+PEEP5 cm H2O 1 min(T6)、15 min(T7)、肺复张前(T8)、肺复张即刻(T9)和肺复张后1 min(T10)时记录SVV、CI和SVI.SVV＜ 13％为正常值.结果 患者术中血液动力学平稳,CI和SⅥ均在正常范围内波动.T9时SVV＞13％,其余各时间点均＜13％.SVV T2,3之间差异无统计学意义,T5～7之间差异均无统计学意义(P＞0.05);T9时SVV较T8.10时升高(P＜0.01).结论 肺叶切除术中,单肺通气以及单肺通气联合PEEP 5 cm H2O时SVV可用于指导液体治疗的判断,而在肺复张时SVV不能指导液体治疗.     

胸科手术中不同年龄组患者血流动力学监测有效指标的探讨

目的探讨基于FloTrac/Vigileo系统对胸科手术中不同年龄组患者血流动力学监测的有效指标。方法选取全麻下行胸腔镜肺癌根治术30例的患者,分为老年组(60～79岁)15例和中年组(40～59岁)15例。观察并记录2组患者在麻醉诱导后5 min(T_0)、侧卧位后5 min(T_1)、单肺通气(OLV)5 min(T_2)、OLV 15 min(T_3)、OLV 30 min(T_4)、恢复双肺通气(TLV) 5 min(T_5)、恢复TLV 15 min(T_6)、转平卧位后5 min(T_7)的FloTrac/Vigileo系统的血流动力学指标,心输血量(CO)、每搏量(SV)、每搏量变异率(SVV)和心率(HR)、平均动脉压(MAP)及中心静脉压(CVP)的变化。结果 2组患者无显著人口统计学差异(P0.05)。2组患者其他时间点的HR、MAP及CO、SV与T_0时比较,差异无统计学意义(P0.05)。中年组患者其他时间点的CVP和SVV与T_0时比较差异无统计学意义(P0.05)。老年组患者的T_1、T_4时的CVP、SVV与T_6、T_0时的差异有统计学意义(P0.05)。T_4、T_6时2组患者的CVP和SVV差异有统计学意义(P0.05),而其他时间点比较差异无统计学意义(P0.05)。老年组患者的CVP和SVV呈正相关(r=0.61,P0.01)。结论基于FloTrac/Vigileo系统的血流动力学监测,老年组和中年组比较发现,SVV在老年组胸腔镜肺癌根治术中更有监测意义。     

目标容量填充对沙滩椅位下骨科肩关节镜手术患者血流动力学的影响

目的评价FloTrac/Vigileo系统监测常规容量填充和目标靶控容量填充对沙滩椅位(beach chair position,BCP)下骨科肩关节镜手术患者血流动力学的影响。方法选择择期行肩部关节镜手术患者30例,男17例,女13例,年龄18~65岁,体重49~68kg,ASAⅠ或Ⅱ级,随机分为两组:常规容量填充组(R组)和FloTrac/Vigileo指导下目标靶控容量填充组(S组),每组15例。R组麻醉诱导后30 min内予以10 ml/kg羟乙基淀粉130/0.4快速静滴行容量填充;S组使用FloTrac/Vigileo系统监测MAP、每搏变异度(SVV)、每搏输出量指数(SVI)和心脏指数(CI),当SVV13%时,5min内静注3 ml/kg羟乙基淀粉130/0.4氯化钠注射液后观察各项指标变化,当SVV13%,观察CI变化(1)CI2.5L·min-1·m-2时,给予多巴胺0.5~1μg·kg-1 min-1,至CI2.5L·min-1·m-2;(2)若CI2.5L·min-1·m-2,不予处理,观察SVV、MAP、CI的变化。记录麻醉诱导前(T1)、诱导后3min(T2)、BCP时(T3)、BCP后5 min(T4)、30 min(T5)以及手术结束平卧位(T6)的MAP、HR、CI、SVI、SVV;记录两组患者麻醉期间血管活性药物的用量、术中用于容量填充的胶体液用量、胶体液总量以及液体总量;记录患者不良反应的发生情况。结果与T1时比较,T3~T5时两组MAP、CI、SVI明显降低(P0.05);与T2时比较,T3~T5时R组SVV明显升高(P0.05)。T3~T5时S组MAP、CI、SVI明显高于R组,而SVV明显低于R组(P0.05)。S组术中用于容量填充的胶体液用量、胶体液总量以及液体总量明显多于R组(P0.05),两组晶体液总量差异无统计学意义。S组术中麻黄碱、多巴胺用量、尿量明显少于R组,低血压发生率明显低于R组(P0.05)。结论以MAP、CI、SVV为目标靶控容量填充模式较传统容量填充可更为安全有效稳定BCP引起的血流动力学波动。     

每搏变异度监测胸腔镜手术患者单肺通气时血容量变化的准确性

目的 评价每搏变异度(SVV)监测胸腔镜手术患者单肺通气时血容量变化的准确性.方法 择期行胸腔镜手术患者22例,性别不限,年龄18～60岁,体重51～77 kg,ASA分级Ⅰ或Ⅱ级.麻醉诱导后置入双腔支气管导管,行双肺机械通气,进胸前改为单肺通气,通气参数:潮气量8 ml/kg,通气频率10～14次/min,吸呼比1∶2,氧浓度100%,PEEP 0,维持PETCO2 35～40 mm Hg.分别于双肺通气5 min和单肺通气30 min时进行容量负荷试验,于10 min内静脉输注6%羟乙基淀粉(HES)5 ml/kg.于双肺通气时输注HES前即刻和输注HES结束后3 min(T1.2)、单肺通气时输注HES前即刻和输注HES结束后3 min(T3.4)时,记录MAP、HR、CO、和SVV,计算CI及SVV和CI的变化率(△SVV和CI).△CI≥11%为扩容有效,绘制SVV判断血容量变化的ROC曲线,计算曲线下面积(AUC)及其95%可信区间(95%CI).结果 与输注HES前即刻比较,输注HES结束后CO升高,SVV降低(P＜0.05).双肺通气时△SVV与△CI呈负相关,相关系数为-0.710(P＜0.05).ROC曲线分析结果示:SVV监测血容量变化的阈值为11.5%,灵敏度为82%,特异度为92%,AUC为0.880(95%CI 0.580～0.987).单肺通气时△SVV与△CI呈负相关,相关系数为-0.668(P＜0.05).ROC曲线分析结果示:SVV监测血容量变化的阈值为9.5%,灵敏度为77%,特异度为63%,AUC为0.971(95%CI 0.917～1.024).结论 单肺通气并不会影响SVV监测胸腔镜手术患者血容量变化的准确性.     

FloTrac/Vigileo监测不同CO2气腹压对腹腔镜妇科手术患者血流动力学的影响

目的探讨应用FloTrac/Vigileo系统监测CO2气腹下不同腹内压(IAP)对腹腔镜妇科手术患者血流动力学的影响。方法 60例择期行腹腔镜妇科手术患者,按随机数字表法均分为三组:IAP分别为8mmHg(A组)、12mmHg(B组)、15mmHg(C组)。FloTrac/Vigileo系统监测患者血流动力学变化。记录麻醉后5min(T0)、气腹后1min(T1)、气腹后5min改变体位时(T2)、气腹后15min(T3)、气腹结束恢复体位后1min(T4)、5min(T5)时HR、MAP、CVP、外周血管阻力(SVR)和心输出量(CO),记录不良反应的发生情况。结果与T0时比较,T1～T3时三组HR明显增快,MAP和SVR明显升高(P<0.05);T1～T3时A组、T2、T3时B组CVP明显升高(P<0.05);T1～T3时B、C组CO明显降低(P<0.05)。T1～T3时C组的HR明显快于,MAP和SVR明显高于A、B组(P<0.05);T1～T3时B、C组CO明显低于A组,且C组明显低于B组(P<0.05)。C组术中心律失常和术后恶心呕吐的发生率明显高于A、B组(P<0.05)。结论 FloTrac/Vigileo系统监测下的CO2气腹腹内压12mmHg对血流动力学影响较小,适合腹腔镜妇科手术患者。     

FloTrac/Vigileo监测下不同体位腹腔镜手术患者血流动力学的变化

目的探讨FloTrac/Vigileo监测下不同体位对腹腔镜阑尾切除术患者血流动力学的影响。方法拟行腹腔镜阑尾切除术患者60例,随机分为三组,每组20例,手术时分别为头低脚高位10°(A组)、20°(B组)和30°(C组)。麻醉前行左桡动脉穿刺连接FloTrac/Vigileo系统。记录气腹前(T0)、气腹后1min(T1)、5min稳定后改变体位时(T2)、气腹后20min(T3)、气腹结束后1 min(T4)及5min稳定后恢复体位时(T5)的HR、MAP、心输出量(CO)、心脏指数(CI)和每搏量(SV),并记录气腹时间和手术时间。结果与T0时比较,T1~T3时三组HR明显增快,MAP明显升高(P0.05);与T1时比较,T2、T3时C组CO及SV明显升高(P0.05)。与C组比较,T2、T3时A、B组CO及SV明显降低(P0.05)。与C组比较,A、B组气腹时间及手术时间明显延长(P0.05)。结论头低脚高位30°下行腹腔镜阑尾切除手术,患者血流动力学的变化在临床安全范围内,且手术时间及气腹时间较10°和20°短。     

动脉压力波形分析技术在急性等容血液稀释中的应用

目的 应用动脉压力波形分析技术(FloTrac/Vigileo系统)来观察心脏手术患者急性等容血液稀释(ANH)时的血流动力学变化.方法 20例拟在心肺转流(CPB)下择期行心脏手术患者随机均分为A、B两组,全麻后行ANH,目标血细胞比容(Hct)为32%,放血速度分别为20 ml/min(A组)和40 ml/min(B组).于ANH前(T0)、ANH开始后5 min(T1)、10 min(T2)、ANH结束时(T3)、ANH结束后10 min(T4)记录HR、MAP、CVP及FloTrac/Vigileo系统测得的心脏指数(CI)、每搏量指数(SVI)、全身血管阻力指数(SVRI)、每搏量变异度(SVV)等指标.结果 两组ANH期间血流动力学变化均无统计学意义;但SVV在T1～T3时较T0时明显增高(P＜0.01),而且B组SVV明显高于A组(P＜0.05).结论 心脏手术患者术前进行ANH是安全的,动脉压力波形分析技术能对其进行方便的监测.SVV能预测机体对输液治疗的反应.     

目标导向液体治疗对老年单肺通气患者局部脑氧饱和度及血流动力学的影响

目的观察目标导向液体治疗(goal-directed fluid therapy,GDFT)对老年单肺通气患者局部脑氧饱和度(rSO_2)及血流动力学的影响。方法选择择期全麻下行中段食管癌根治术患者58例,男44例,女14例,年龄65~79岁,ASAⅡ或Ⅲ级,采用随机数字表法分为两组:传统液体治疗组(C组)和GDFT组(G组),每组29例。所有患者均通过桡动脉连接FloTrac/Vigileo监测系统连续监测MAP、心输出量(CO)、心脏指数(CI)和每搏量变异度(SVV)。C组根据MAP、CVP及尿量行传统液体疗法;G组于SVV指导下行GDFT,维持CI 2.5~4.0L·min~(-1)·m~(-2)。所有患者于术中持续监测rSO_2,计算术中rSO_2平均值(rSO_2)、术中rSO_2最小值(rSO_2min)以及rSO_2较基础值下降的最大百分比(rSO_(2%max));记录入室建立监测后(T_1)、单肺通气前(T_2)、单肺通气30 min(T_3)、单肺通气1h(T_4)及术毕(T_5)时的MAP、HR、CVP、CI及SVV;记录术中晶体液和胶体液用量、总输液量、出血量、尿量以及血管活性药物的使用情况。结果与C组比较,T_3、T_4时G组MAP明显升高(P0.05);T_3~T_5时G组CVP明显下降、CI明显升高(P0.05);T_2~T_5时G组SVV明显下降(P0.05)。G组rSO_(2%max)明显低于C组(P0.05),两组rSO_2和rSO_(2min)差异无统计学意义。与C组比较,G组术中晶体液用量[(668±187)ml vs(1 052±221)ml]、总输液量[(1 212±318)ml vs(1 519±329)ml]、尿量[(211±47)ml vs(278±54)ml]及血管活性药物使用[4例(14%)vs 14例(48%)]明显减少(P0.05),胶体液用量明显增加[(544±103)ml vs(467±94)ml,P0.05]。结论基于SVV的GDFT可稳定老年患者单肺通气时的血流动力学,维持脑氧供需稳定。     

FloTrac/Vigileo监测系统对消化内镜治疗中二氧化碳注射心血管效应的评价作用

利用FloTrac/Vigileo监测系统研究消化内镜治疗中二氧化碳注射对全身麻醉机械通气患者循环功能的影响。择期行消化内镜治疗术患者30例,ASAⅠ级或Ⅱ级,年龄55~60岁,体质量55~76 kg。术前排除心肺疾患患者。所有患者采用相同的全身麻醉方法:静脉快速诱导气管插管成功后,以丙泊酚、瑞芬太尼持续泵入,间断推注肌松药,维持麻醉深度,采用脑电双频谱监测仪指导并维持患者的BIS值在40~60,使其麻醉深度保持一定范围;行左侧桡动脉穿刺置管,连接FloTrac传感器和Vigileo监测仪连续监测血压(SBP、DBP、MAP)、心排出量(CO)、每搏输出量(SV)、每搏输出量变异度(SVV);行右侧颈内静脉穿刺置管监测中心静脉压(CVP)。分别在麻醉操作完成后5 min和二氧化碳注射后5、10、15min记录以上数据。并计算出体循环外周阻力(SVR)的数值。二氧化碳注射后,患者CVP升高(P0.05),SVV升高(P0.05),心率增快(P0.05),SV降低(P0.05),CO增加(P0.05),SVR增加(P0.05),血压升高(P0.05)。消化内镜治疗中二氧化碳注射对全身麻醉机械通气患者的血流动力学会产生显著地改变。     

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.     

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.