硬膜外麻醉辅用咪唑安定氯胺酮对腹腔镜手术患者平均动脉压的影响

目的:探讨硬膜外麻醉辅用咪唑安定氯胺酮对腹腔镜手术患者平均动脉压（MAP）的影响。方法:回顾分析92例行此麻醉方法患者于注药前、注咪唑安定、注混合药及术中10min、30min时的血压。结果:注混合药后血压各值明显低子注药前（P<0.05）,且较平稳。结论:腹腔镜手术患者行硬膜外麻醉同时辅用咪唑安定和氯胺酮,术中血压下降且保持平稳。     

听觉诱发电位指数在老年高血压患者异氟醚麻醉中的应用

目的　研究听觉诱发电位指数 (AEPI)调控异氟醚麻醉深度对老年高血压患者手术中血压控制的可行性。方法　择期行胃切除术合并高血压的老年患者 2 8例 ,ASAⅡ～Ⅲ级 ,随机分两组 ,每组 14例。Ⅰ组通过AEPI监测对麻醉深度行反馈调控 ;Ⅱ组不用AEPI调控 ,仅根据血液动力学的变化来调整麻醉深度。两组患者麻醉诱导均用芬太尼、丙泊酚和琥珀胆碱 ;麻醉维持用氧化亚氮、异氟醚吸入。记录基础值、插管时、插管后 5min、切皮时、术中探查时、停药时、睁眼时和拔管时 8个时间点的HR、SBP、DBP、MAP和AEPI。结果　Ⅰ、Ⅱ组在插管时的SBP、DBP和MAP均显著低于基础值 (P <0 0 5 )。但插管后 5min时与基础值比较 ,Ⅱ组血压有回升 ,Ⅰ组仍降低 (P <0 0 5 )。术中切皮时、探查时、停药时 ,Ⅰ组血液动力学变化较为平稳 ,且低于基础值 (P <0 0 5 ) ;而Ⅱ组中 ,在切皮时和探查时明显上升 (P <0 0 5 )。两组患者在基础值、睁眼时及拔管时的AEPI值均无明显差异 ;但术中各时点Ⅰ组明显低于Ⅱ组 (P <0 0 5 )。结论　在老年高血压患者手术中 ,通过AEPI的监测调节异氟醚麻醉深度可维持稳定的血液动力学 ,有利于保障患者的安全     

右美托嘧定对腹腔镜直肠癌根治术老年患者局部脑氧饱和度和术后认知功能的影响

观察右美托咪定对腹腔镜直肠癌根治术老年患者局部脑氧饱和度和术后认知功能的影响。选择择期行腹腔镜直肠癌根治手术的老年患者50例,年龄65～80岁,ASA分级Ⅰ～Ⅲ级,随机均分为右美托咪定组和对照组。右美托咪定组(右美组)在全麻诱导插管后泵注右美托咪定0.5μg/kg,15 min泵注完毕,然后以0.5μg/(kg·h)的速度维持泵注至手术结束前30 min;对照组泵入等量生理盐水。术中使用Covidien脑氧与区域监测系统监测r SO_2。记录入室时(T1)、诱导插管后(T2)、气腹后60 min(T3)和苏醒后(T4)的r SO_2、MAP、PaO_2和PaCO_2。于术前1 d、术后1、3和7 d用简易精神状态检查量表(MMSE)进行评分,记录患者术后认知功能障碍(POCD)发生情况。组内比较,T2、T3、T4时刻两组r SO_2、PaCO_2值明显高于T1时刻(P0.05);两组间同一时刻比较无明显差异。术后1 d右美组MMSE评分明显高于对照组(P0.05)。右美组有1例(4%)患者发生POCD,明显低于对照组的6例(24%)(P0.05)。右美托咪定用于老年腹腔镜直肠癌根治手术对局部脑氧饱和度未见明显影响,但可减少POCD的发生率。     

不同BIS值对全麻下老年患者腹部手术术后早期认知功能及S100β蛋白的影响

目的研究不同BIS值对全麻下老年患者腹部手术术后早期认知功能及S100β蛋白的影响。方法选择全麻下择期行腹部手术的患者50例,男34例,女16例,年龄65~75岁,ASAⅠ或Ⅱ级,按照随机数字表法分为浅麻醉组(L组)和深麻醉组(D组),每组25例。L组BIS值维持在50~59,D组BIS值维持在30~39。记录入室后静卧5min(T0)、插管前即刻(T1)、手术切皮即刻(T2)、手术进行2h时(T3)、手术进行3h时(T4)、术毕(T5)时的BP、HR、SpO2、ECG、PETCO2、吸入麻醉药浓度、BIS值;记录两组的麻醉时间、手术时间、术后1d的VAS评分、丙泊酚用量、芬太尼用量、咪达唑仑用量。于麻醉前10min、术毕及术后24、48h时采集血液标本,测定S100β蛋白浓度;于术前1d及术后1、3、7d随访记录患者MMSE评分及TMT完成时间。结果 D组T2、T3、T4时BIS值明显低于L组(P0.05);D组丙泊酚用量明显多于L组(P0.05)。与麻醉前10min比较,术毕和术后48h两组血清S100β蛋白含量明显升高,术后24h两组血清S100β蛋白含量有增高趋势,但差异无统计学意义;与术毕比较,术后24h两组血清S100β蛋白含量明显降低(P0.05),L组术毕、术后24h血清S100β蛋白含量明显高于D组(P0.05)。与术前1d比较,术后1d两组MMSE评分明显降低,术后3dL组MMSE评分明显降低(P0.01);与术后3d比较,术后7dL组MMSE评分明显升高(P0.01);L组术后1、3d的MMSE评分明显低于D组(P0.05)。与术前1d比较,术后1d两组TMT完成时间明显延长(P0.01);与术后1d比较,术后3d两组TMT完成时间明显缩短(P0.01);与术后3d比较,术后7dL组的TMT完成时间明显缩短(P0.01);术后1、3dL组TMT完成时间明显长于D组(P0.05)。术后1dL组POCD发生率明显高于D组(P0.05)。结论不同麻醉深度均可保证老年患者术中和术后血流动力学平衡,且术后均发生不同程度的认知功能障碍,但术中将BIS值维持在30~39的深麻醉组血清S100β蛋白水平及早期POCD的发生率较低,术后认知功能损伤程度较轻。     

芬太尼复合小剂量氯胺酮用于胸部手术患者术后镇痛

单纯芬太尼用于患者术后镇痛,镇痛效果确切,但对于老年患者来说,芬太尼的使用可能带来嗜睡、呼吸抑制等并发症。研究表明小剂量氯胺酮仍具有较好的镇痛作用,同时并无大剂量使用时出现的认知功能异常。本文将芬太尼复合小剂量氯胺酮用于60岁以上老年患者胸科术后镇痛,取得了可靠     

右美托咪定对老年患者全麻术后认知功能障碍的影响

目的探讨右美托咪定对老年患者全麻术后认知功能障碍(POCD)的影响。方法选择我院2013年3月~2014年2月择期全麻下腹部手术的老年患者180例,年龄65~82岁,ASAⅡ或Ⅲ级,随机均分为右美托咪定组(DH组)和生理盐水组(HS组)。DH组在全麻诱导开始,10min内静脉泵入0.8μg/kg右美托咪定,随后以0.2~0.5μg·kg-1·h-1维持泵注;HS组静脉泵等量生理盐水。观察并记录术前10min、拔管前10min、拔管后30min的MAP、HR和SpO2。记录术中丙泊酚、瑞芬太尼用量、自主呼吸恢复时间(停止泵注静脉麻醉药至自主呼吸恢复时间)、拔管时间和定向力恢复时间。应用简易精神状态量表记录患者术前1d、术后6h、1、3dMMSE评分,并记录发生POCD例数。结果与HS组比较,拔管前10min、拔管后30min DH组MAP明显降低、HR明显减慢(P0.05)。与HS组比较,DH组术中丙泊酚和瑞芬太尼用量明显减少(P0.05),自主呼吸恢复时间、拔管时间和定向力恢复时间明显缩短(P0.05)。与术前1d比较,术后6h、1dHS组MMSE评分明显降低(P0.05)。与HS组比较,术后6hDH组MMSE评分明显升高(P0.01)。DH组发生POCD 8例(8.89%),明显低于HS组19例(21.11%)(P0.05)。结论右美托咪定能提高全麻老年患者术中血流动力学稳定性,对术后认知功能具有一定保护作用。     

老年患者匀速注射丙泊酚的量效关系及其对痛阈的影响

目的 观察在不同剂量丙泊酚镇静下老年患者BIS、MAP及HR的变化趋势及其对痛阈的影响.方法 选择年龄65～89岁,ASA Ⅰ或Ⅱ级.行择期手术的患者40例,随机均分为四组,分别接受4个不同剂量的丙泊酚匀速静脉注射.即Ⅰ组0.75 mg/kg、Ⅱ组1 mg/kg、Ⅲ组1.25mg/kg、Ⅳ组1.5 mg/kg,注射时间均为1 min.改良警觉/镇静(OAA/S)评分法测各组丙泊酚镇静催眠深度.微电流致痛法测各组痛阈.分别于注药前、注药后1 min测四组BIS、HR、MAP及痛阈低值和高值.结果 注药后1 min,Ⅰ、Ⅱ组OAA/S评分均达到2或1分,Ⅲ、Ⅳ组0分.Ⅰ、Ⅱ组BIS值分别是70.4±12.3、68.7±6.4,Ⅲ、Ⅳ组的BIS是56.3±13.3及48.3±9.8,其中注药后1 minⅢ、Ⅳ组的BIS值分别显著低于Ⅰ、Ⅱ组(P<0.05或P<0.01).丙泊酚用药剂量与BIS之间呈显著负相关(r=-0.648,P<0.01),回归方程:BIS=96.626-31.719×丙泊酚剂量(r2=0.419,P<0.01).注药后1min,四组的MAP均显著低于注药前(P<0.01);组间比较,Ⅳ组显著低于同时点的Ⅰ、Ⅱ组(P<0.05),而注药前后各组HR值组内、组间比较差异均无统计学意义.注药后1 min的Ⅲ、Ⅳ组的痛阈低值高于注药前,也高于同时点的Ⅰ、Ⅱ组(P<0.05或P<0.01);两组的痛阈高值也显著高于注药前(P<0.05或P<0.01).结论 随着丙泊酚用药剂量的增加,BIS值相应降低,两者呈线性负相关.1.25、1.5 mg/kg的丙泊酚单次匀速静注后可满足老人全麻术中镇静催眠的需求,并使痛阈水平上升,疼痛敏感性降低.     

比较全麻与腰硬联合麻醉对股骨近端骨折老年患者术中血液动力学指标的影响

目的比较全麻与腰硬联合麻醉对股骨近端骨折老年患者术中血液动力学指标的影响。方法择期行股骨近端骨折手术患者102例,年龄43~75岁,BMI19~34 kg/m~2,ASAⅠ~Ⅱ级。采用随机数字表法分为腰硬联合组(腰硬组)与气管插管全身麻醉组(全麻组),各51例。比较2组患者麻醉前(T0)、麻醉后5 min(T1)、术毕时(T2)的血液动力学指标(DBP、HR、SpO2)。记录术中及术后不良反应发生情况。结果 2组患者T0时的DBP、HR、SpO2差异无统计学意义(P>0.05)。T1、T2时腰硬组患者的DBP、HR、SpO2均优于全麻组;术中高血压及术后头晕、恶心呕吐、肺部感染、认知功能障碍等不良反应发生率明显低于全麻组,但术中低血压发生率则明显高于全麻组。差异均有统计学意义(P<0.05)。结论腰硬联合麻醉用于老年股骨近端骨折患者手术,术中血流动力学指标稳定,且不良反应轻微,更利于老年患者术后恢复。     

麻黄碱与异丙酚、芬太尼配伍用于无痛胃镜的临床观察

目的 观察小剂量麻黄碱与异丙酚、芬太尼配伍用于无痛胃镜患者BP、HR、R的变化,并与单纯使用异丙酚、芬太尼进行比较,研究麻黄碱减少异丙酚、芬太尼对呼吸、循环系统影响的可行性.方法 选择门诊ASAⅠ～Ⅱ级需行胃镜下检查并治疗的患者200例,随机分为两组,异丙酚200 mg、芬太尼0.1 mg称为F组,异丙酚200 mg、芬太尼0.1 mg、麻黄碱30 mg称为MF组.每组100例.分别于麻醉前3 min、注药后3 min、手术后3 min测量并记录BP、HR、R,并于手术后10 min行VAS评分及麻醉效果满意的评定.结果 两组患者术前BP、HR、R比较差异无统计学意义.F组BP、HR、R术中较术前明显下降(P＜0.05),但术后恢复至术前水平.MF组术中、术后BP、HR、R与麻醉前比较差异无统计学意义(P＞0.05).结论 小剂量麻黄碱与异丙酚、芬太尼配伍用于无痛胃镜的麻醉可明显减轻异丙酚、芬太尼对循环、呼吸系统的影响,可完全抵消异丙酚、芬太尼对循环系统的抑制作用,具有麻醉效果好、对循环干扰小、安全可靠的优点,是无痛胃镜可供选择的较好的麻醉方法之一.     

小剂量氯胺酮镇痛对宫颈癌病人Th细胞偏移和术后苏醒质量的影响

目的 观察宫颈癌术中、术后持续静脉输注小剂量氯胺酮对Th细胞偏移和术毕苏醒质量的影响.方法 40例择期全凭静脉麻醉下行妇科宫颈癌根治术病人,ASA Ⅰ或Ⅱ级,年龄55～65岁绝经后妇女,随机均分为氯胺酮组(K组)、对照组(C组).全麻诱导后K组首次静注氯胺酮0.5 mg/kg,随后持续泵注氯胺酮4μg·kg<'-1>·min<'-1>至术毕;C组全麻诱导后给予等量生理盐水.术后两组静脉镇痛方案相同,但K组加用氯胺酮2μg·kg<'-1>·min<'-1>泵注.麻醉前、术后2、24、48 h采集外周静脉血,以酶联免疫法测定血浆中细胞因子干扰素-γ(IFN-γ)、白细胞介素-4(IL-4)浓度,以IFN-γ/IL-4评估Thl/Th2亚群比值.记录术后2、24、48 h视觉模拟评分(VAS)和术毕停药后呼之睁眼时间、拔管时间及拔管后躁动发生率.结果 与麻醉前比较,术后2、24、48 h的两组IFN-γ浓度、IFN-γ/IL-4比值均明显上升(P<0.01);术后48 h K组的血浆IFN-γ/IL-4比值明显高于C组(P<0.01);术后2、24、48 h K组VAS明显低于C组(P<0.05).K组呼之睁眼时间、拔管时间明显长于C组(P<0.05);K组拔管后躁动发生率低于C组(P<0.05).结论 小剂量氯胺酮镇痛不仅可以改善宫颈癌根治术后镇痛和苏醒质量并能减缓Th细胞向Th2偏移,但会延长拔管时间.     

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.     

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.     

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.     

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.