3%高渗盐水降低颅内肿瘤患者颅内压的可行性

目的观察3%高渗盐水(HTS)对颅内肿瘤患者脑脊液压力(CSFP)、血液动力学及电解质的影响,探讨3%HTS用于降低颅内肿瘤患者颅内压的可行性。方法择期行大脑半球胶质瘤切除术患者加例,男23例,女17例,ASA Ⅰ或Ⅱ级,随机分为两组(n=20),HTS组和M组,麻醉诱导前行L3,4刺置管监测CSFP。两组均行静吸复合麻醉,异氟醚呼气末浓度达1MAC后,在15 min内输注3%HTS(5.33 ml/kg)和20%甘露醇(1g/kg)。在输注前即刻(T0)、输注后15、30、60、90、120 min(T1-5)记录平均动脉压(MAP)、心率(HR)、中心静脉压(CVP)、尿量,采集5 ml动脉血测定血浆Na 、K 、pH、血浆渗透压;在T0-4监测CSFP,计算脑灌注压(CPP)。结果两组各时点MAP和HR比较差异无统计学意义(P>0.05)。与T0时比较,HTS组CSFP在T2-4时降低,M组在T3、T4时降低,HTS组CVP在T1-4 时升高,M组在T4、T5时降低,两组各时点血浆渗透压均升高,两组不同时点血浆Na 和K 浓度均有改变但仍在正常范围内(P<0.05)。与M组比较,HTS组CSFP在T2时降低,CVP在T5时升高,尿量在T1-2、T2-3、T3-4、T4-5时段减少(P<0.05)。结论3%HTS可安全地用于颅内肿瘤患者,其降低颅内压的作用优于20%甘露醇,且在降低颅内压的同时,不影响血液动力学。     

瑞芬太尼用于颅脑手术控制性降压的研究

目的 观察瑞芬太尼用于颅脑手术控制性降压对血流动力学和脑氧代谢的影响.方法 择期行颅脑手术患者30例,ASA Ⅰ或Ⅱ级,随机均分为瑞芬太尼组(R组)和硝普钠组(N组).术中监测和记录手术前、降压前、达到目标血压0 rain(T0)、5 min(T1)、10 min(T2)、20 min(T3)、30min(T4)及停止降压5 min(T5)、10 min(T6)、30 min(T7)时的HR、MAP、CVP、P盯C02和spO2,并抽取桡动脉、右颈内静脉球部血标本测血气,计算麻醉后、手术前、降压前、达到目标血压10 min的颈内静脉球部血氧含量差(Da-jvO2)、脑氧代谢率(CERO2)、RPP.结果 R组各时点HR慢于N组(P<0.05).R组和N组的Da-jvO2、CERO2在降压时均下降(P<0.05),但两组差异无统计学意义.结论 瑞芬太尼用于颅脑手术控制性降压在改善脑氧代谢的同时不增快HR.     

丙泊酚复合异氟醚控制性降压对脑氧代谢的影响

目的 探讨丙泊酚复合异氟醚控制性降压期间对颅脑手术病人脑氧代谢的影响。方法 选择28例ASA Ⅰ～Ⅱ级的择期脑瘤手术病人,随机均分为异氟醚降压（Ⅰ）组,丙泊酚复合异氟醚联合降压（Ⅱ）组。降压幅度与诱导前相比较,MAP下降30％～40％,维持30min。分别于降压前、中、后进行血气分析和血糖测定,计算动颈内静脉血氧含量差（Da-jvO2）和脑氧代谢率（CERO2）。结果 两组降压效果无显著性差异,降压期间HR均明显加快;降压30min时Da-jvO2、CERO2 Ⅱ组低于Ⅰ组（P〈0．05,P〈0．01）;两组于降压前BGa、BGjv渐升高,而Da-jvBG降压前较麻醉前明显下降,组间无显著性差异。结论 丙泊酚复合异氟醚控制性降压期间降低脑氧代谢的作用优于单纯使用异氟醚。     

允许性高碳酸血症机械通气对老年患者脑氧代谢及术后认知功能的影响

目的 探讨允许性高碳酸血症机械通气对老年患者脑氧代谢和术后认知功能的影响.方法 择期全麻下腹部手术老年患者120例,年龄65 ～ 80岁,体重45 ～ 66 kg,ASA分级Ⅰ～Ⅲ级,采用随机数字表法,将患者随机分为2组(n=60):常规通气组(R组)和允许性高碳酸血症机械通气组(H组).H组通气参数:VT 6～8ml/kg,RR 12～ 14次/min,吸呼比1:2,维持PaC02 45 ～ 65 mm Hg,pH值＞7.2,R组通气参数:VT10 ～ 12 ml/kg,RR 14～ 16次/min,吸呼比1:2,维持PaCO2 35～ 45 mm Hg.于气管插管即刻(T0)、气管插管后5 min(T1)、15min(T2)、3O min(T3)时经桡动脉、颈内静脉球部采集血样行血气分析,计算动脉-颈内静脉血氧含量差(Da-jvO2)和脑氧摄取率(CERO2).于术前1d、术后24、48 h、1、2周时采用简易智能状态检查表(MMSE)评分评价术后认知功能.结果 与R组相比,H组T1～T3时PET CO2和paCO2升高,pH值、Da-jvO2和CERO2降低,术后MMSE评分升高,术后认知功能障碍发生率降低(P＜ 0.05或0.01);与T0时相比,H组T1～T3时PETCO2和PCO2升高,pH值、Da-jvO2和CERO2降低,2组T1 ～T3时Da-jvO2和CERO2降低,术后24 h～1周MMSE评分降低(P＜0.01).结论 允许性高碳酸血症机械通气可改善老年患者术中脑氧代谢,减轻术后认知功能障碍.     

不同剂量尼莫地平对老年腹部手术患者术后认知功能和脑氧代谢的影响

目的 观察不同剂量尼莫地平对老年腹部手术患者术后认知功能和脑氧代谢的影响.方法 择期行腹部手术的老年患者120例,年龄65～83岁,ASA Ⅰ或Ⅱ级,随机均分为三组:Ⅰ组在全麻诱导插管后,持续输注尼莫地平15μg·kg-1·h-1至术毕;Ⅱ组输注尼莫地平7.5μg·kg-1·h-1至术毕;Ⅲ组输注等容量生理盐水.于术前1 d、术后4 d测定简易智力状态检查表(MMSE)评分,术后比术前减少2分或2分以上判为发生术后认知功能障碍(POCD).各组于麻醉诱导前(T0)、麻醉后60 min(T1)和术毕(T2)时,同步采取桡动脉和颈内静脉球部血标本行血气分析,计算动脉血氧含量(CaO2)、颈内静脉球部血氧含量(CjvO2)、动-颈内静脉血氧含量差(Da-jvO2)和脑氧摄取率(CERO2).结果 三组共22例术后4 d发生POCD,Ⅰ组5例(12.5%)、Ⅱ组8例(20.0%)、Ⅲ组9例(22.5%).Ⅰ组POCD发生率明显低于Ⅲ组(P＜0.05).T1、T2时Ⅰ组Da-jvO2和CERO2明显低于T0时和Ⅲ组(P＜0.01).T2时Ⅱ组Da-jvO2和CERO2明显低于T0时和Ⅲ组(P＜0.05).结论 尼莫地平15μg·kg-1·h-1能减少POCD的发生,可能与改善脑氧代谢有关.     

参附注射液对颅脑手术病人脑氧供需平衡的影响

目的　观察参附注射液 (SF)对颅脑手术病人脑氧供需平衡的影响。方法　 30例ASAⅠ～Ⅱ级幕上肿瘤行择期开颅手术的病人 ,随机分为对照组 (C组 )和SF组 ,每组 15例。术中切开硬脑膜后 ,SF组用 0 9%生理盐水将 5 0ml参附注射液稀释至 2 0 0ml于 2 0min内静脉输入 ;C组在同一时间给予生理盐水 2 0 0ml。分别于输注前 (T1)、输注完即刻 (T2 )及输注后 30min(T3 )三个时点同步采集颈静脉球和足背动脉血行血气分析 ,并计算动脉、颈静脉球血氧含量 (CaO2 、CjvO2 )、动 颈内静脉血氧含量差 (Ca jvO2 )及脑氧摄取率 (CERO2 )。结果　输注SF前后两组间HR和MAP无明显变化 (P >0 0 5 ) ;颈内静脉血氧饱和度 (SjvO2 ) ,颈内静脉血氧分压 (PjvO2 ) ,CaO2 ,Ca jvO2 及CERO2等指标在SF输注前后均无明显变化 ,两组间亦无显著性差异 (P >0 0 5 )。结论　参附注射液在神经外科围术期应用对脑的氧供需平衡无明显影响     

不同Narcotrend指数下老年患者全麻术中脑氧代谢的比较

目的比较不同Narcotrend指数(Narcotrend index,NTI)下老年患者全麻术中脑氧代谢的变化。方法择期行腹部手术(术式不限,手术时间短于2h)的老年患者90例,随机均分为A、B、C组,术中NTI分别维持在D0、D2和E1。分别采集麻醉诱导前(T0)、NTI达到预定值后10min(T1)、30min(T2)、关腹即刻(T3)和术毕时(T4)桡动脉及颈静脉球部血样行血气分析,记录并计算颈内静脉球部血氧含量(SjvO2)、桡动脉-颈内静脉球部血氧含量差(Da-jvO2)及乳酸差(VADL)、脑氧摄取率(CERO2)。结果 T1~T4时B和C组SjvO2明显高于,Da-jvO2、CERO2明显低于T0时和A组(P0.05);T1~T4时C组SjvO2明显高于B组(P0.05)。结论老年患者全麻术中NTI维持在D0、D2和E1时,脑氧代谢虽发生变化,但并未破坏大脑正常的氧供-氧耗平衡。     

急性等容血液稀释联合低中心静脉压对肝癌手术脑氧代谢的影响

目的观察急性等容血液稀释(ANH)联合低中心静脉压(LCVP)在肝癌手术中对患者脑氧代谢的影响。方法拟行肝癌手术患者40例,随机均分为两组。ANH+LCVP组全麻后先进行ANH,然后进行LCVP控制,在肝脏实质完全离断前CVP控制在0～5cmH2O,肝实质切除止血彻底后将CVP恢复至7～8cmH2O;常规治疗组手术中CVP维持在7～8cmH2O。分别于入室后(T0)、采血后5min(T1)、肝癌切除后5min(T2)、恢复容量后5min(T3)抽取动脉、颈内静脉球部的血作血气分析,检测动脉、颈内静脉血氧饱和度(SaO2、SjvO2)、动脉、颈内静脉血氧分压(PaO2、PjvO2)、Hb和Hct,并计算动脉、颈内静脉球部血氧含量(CaO2、CjvO2)、脑氧摄取率(CERO2)、动脉、颈内静脉球部血氧含量差(Da-jvO2)和乳酸差(VADL)。结果与T0时比较,T2、T3时两组Hb、Hct值明显降低(P<0.05),T1～T3时ANH+LCVP组SjvO2明显升高(P<0.05),CERO2、Da-jvO2明显降低(P<0.05),T2、T3时常规治疗组CERO2、Da-jvO2明显降低(P<0.05)。与T2时比较,T3时ANH+LCVP组Hb、Hct值明显升高(P<0.05),常规治疗组明显下降(P<0.05)。与常规治疗组比较,ANH+LCVP组T1、T2时Hb、Hct值明显降低、而T3时明显升高(P<0.05),T1～T3时SjvO2、T3时Da-jvO2明显升高(P<0.05);而T1时Da-jvO2明显降低(P<0.05)。结论急性等容血液稀释联合低中心静脉压技术可以安全应用于肝癌手术中,对脑氧代谢无明显不良影响。     

右美托咪定对体外循环下心脏瓣膜置换术患者脑损伤的影响

目的 评价右美托咪定对体外循环(CPBB)下心脏瓣膜置换术患者脑损伤的影响 方法 择期CPB下心脏瓣膜置换术患者40例,性别不限,年龄43～64岁,ASA分级Ⅱ或Ⅲ级,采用随机数字表法,将患者随机分为两组(n=20):对照组(C组)和右美托咪定组(D组).麻醉诱导前D组静脉注射右美托咪定0.6 μg/kg(15 min内),随后以0.2 μg·kg-1·h-1速率输注至术毕,C组给予等容量生理盐水.分别于CPB开始前(T1)、升主动脉开放(T2)、CPB结束(T3)及术后6 h(T4)时抽取桡动脉和颈静脉球部血样行血气分析,计算动脉-颈内静脉血氧含量差(Da-jvO2)、脑氧摄取率(CERO2),于T1-4及术后 24 h(T5)时测定预内静脉球部血浆S-100β蛋白和神经元特异性烯醇化酶(NSE)的浓度.结果 与C组比较,D组T2,3时SjvO2升高,Da-jvO2和CERO2降低,T2-4时血浆S-100β蛋白和NSE浓度降低(P＜0.05) 结论 右美托咪定可降低CPB下心脏瓣膜置换术患者脑氧代谢率,减轻脑损伤.     

硬膜外复合全身麻醉下急性高容量血液稀释对手术病人脑代谢的影响

目的 探讨硬膜外复合全身麻醉下急性高容量血液稀释对手术病人脑代谢的影响。方法 选择ASAⅠ或Ⅱ级择期手术病人14例，采用硬膜外阻滞复合全身麻醉，诱导后行右侧颈内静脉球部置管，呼气末异氟醚浓度稳定在1．2％时，经硬膜外导管注入1．33％利多卡因＋0．167％地卡因10ml后开始血液稀释，静脉输入6％羟乙基淀粉20ml／kg，速率50ml／min，分别于稀释前即刻（T0）、稀释后15min（T1）、120min（T2）采取桡动脉和颈内静脉球血，分别进行血气分析、乳酸、血糖、红细胞比容及血红蛋白（Hb）测定，计算动脉一颈内静脉球血血氧含量差[D（a-jv）O2]、脑氧摄取率（CERO2）、脑葡萄糖摄取率（CMRGlu）、动脉一颈内静脉球血乳酸浓度差。结果 与T0比较，T1时颈内静脉球部血氧饱和度（SjvO2）上升，D（a-jv）O2、CERO2下降，T2时D（a—jv）O2下降，T1.2Hb降低（P〈0．05），其余各指标差异无统计学意义。结论 硬膜外复合全身麻醉下急性高容量血液稀释可增加脑氧供应，维持脑氧和能量代谢的稳定。     

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.