咪唑安定和依托咪酯静脉诱导对冠脉搭桥病人血流动力学和氧代谢的影响

目的:观察咪唑安定和依托咪酯诱导对冠心病病人血流动力学和氧代谢的影响。方法:30例行冠脉搭桥手术的病人,随机分为E组(依托咪酯组,n=15)和M组(咪唑安定组,n=15)。在两组病人分别给予咪唑安定或依托咪酯直至睫毛反射消失,继之根据动脉压的变化给予哌库溴胺和芬太尼诱导麻醉,气管插管。观察诱导前、中、后两组病人血流动力学和整体氧代谢的改变。结果:麻醉诱导使两组病人HR、MAP、SVRI、PVRI和VO_2I均明显下降(P<0.05),但与E组相比,M组MAP和SVRI下降更为明显(P<0.05)。同时M组的RVSWI、LVSWI、RVSWI×HR和LVSWI×HR明显下降,而E组无明显改变(P<0.05)。插管后两组的HR、MAP、SVRI和PVRI均有回升。但在E组HR未恢复到诱导前水平,在M组MAP和SVRI未恢复到诱导前水平(P<0.05)。插管后两组病人RVSWI×HR和LVSWI×HR无明显差别。两组病人在诱导过程中CI和DO_2I均无明显改变。结论:与依托咪酯相比咪唑安定与芬太尼合用有较强的协同扩血管作用。依托咪酯诱导可维持较好的心肌氧供、需平衡,更适用于冠脉储备有限的冠心病病人的诱导。     

七氟醚麻醉中阻塞性黄疸患者的血流动力学变化

目的 探讨阻塞性黄疸患者在七氟醚吸入麻醉过程中血流动力学的变化.方法 择期手术患者80例,ASA Ⅰ或Ⅱ级,按照血清总胆红素(sTBL)水平分为观察组(A组,sTBL≥17.1μmol/L)和对照组(B组,sTBL<17.1 μmol/L),每组40例.分别在麻醉诱导前、呼出气七氟醚浓度在1.0 MAC和1.5 MAC并维持10 min时记录血流动力学指标.结果 麻醉诱导前A组MAP、HR、全身血管阻力(SVR)、心脏指数(CI)、肺毛细血管楔压(PCWP)明显低于B组(P<0.05或P<0.01).1.0 MAC时A组MAP、平均肺动脉压(MPAP)、CI、每搏指数(SI)的下降百分率均明显大于B组(P<0.05或P<0.01).1.5MAC时A组患者MPAP、MAP、CI的下降百分率明显大于B组(P<0.05或P<0.01).结论 与非阻塞性黄疸患者比较,阻塞性黄疸患者血流动力学随七氟醚呼出气浓度增加而波动增大.     

非体外循环冠脉搭桥术中心脏移位对血液动力学的影响

目的 观察非体外循环冠脉搭桥术(OPCABG)中暴露术野时心脏位置改变对心血管功能的影响。方法 冠心病多支病变患者47例,年龄50～82岁,术前左室射血分数为0.55±0.14,择期行OPCABG,平均移植血管桥3.2条。采用漂浮导管方法监测血液动力学,分别在麻醉诱导后循环稳定时(T_1)、搬动心脏前(T_2)、吻合前降支时(T_3)、吻合右冠状动脉或后降支时(T_4)、吻合左旋支或对角支时(T_5)、血管吻合完成、心脏恢复自然位置后(T_6)、及手术结束时(T_7)作参数测定。结果 吻合前降支时(T_3),SI和LVSWI有所降低(P<0.01),但CI和SvO_2保持在基础水平。吻合后降支或右冠状动脉、左旋支或对角支时(T4、T5),CI、SI、LVWI、LVSWI、RVWI和RVSWI等明显降低(P<0.01),其中CI较对照值降低18％,LVWI和RVWI降低均为25％,MAP和SvO_2也显著下降(P<0.05～0.01),而HR、RAP、MPAP、PAWP和PVRI则显著增高(P<0.05～0.01)。心脏恢复自然位置后(T_6),CI、LVWI和RVWI恢复到对照值水平。结论 OPCABG术中由于心脏被搬动及移位,可导致明显的心功能损害和血压下降;麻醉手术期间采取可靠的血液动力学监测和有效的心血管功能支持十分必要。     

低浓度七氟醚与异氟醚吸入麻醉对小儿血流动力学的影响

目的 研究低流量七氟醚与异氟醚吸入麻醉对小儿血流动力学的影响.方法 40例1～5岁小儿随机分为七氟醚组(S组)和异氟醚组(I组),每组20例.分别测量呼气末麻醉药浓度为0MAC(T0)、0.5MAC(T1)、1.0MAC(T2)和1.5MAC(T3)稳定5 min后的每搏指数(SI)、心脏指数(CI)、外周血管阻力(SVR)、HR及MAP.结果 与T0时比较,T1时两组MAP和SVR均有降低(P<0.05),其他指标均无明显变化.T2时,SVR和MAP进一步降低,HR略增快和SI略升高,但两组间差异无统计学意义,S组Cl值显著高于Ⅰ组(P<0.05).T3时,S组的HR显著快于Ⅰ组,而SI下降与T0近似;SVR和MAP两组无进一步降低.结论 低浓度七氟醚和异氟醚麻醉对小儿心肌无明显抑制,仅降低MAP和SVR,七氟醚增快HR作用大于异氟醚.     

七氟醚麻醉对胰岛素分泌和糖代谢的影响

Oyama等曾经报导七氟醚-N_2O麻醉时,胰岛素分泌减少。Iwasaka等也报导吸入麻醉药如氟烷、安氟醚或异氟醚麻醉,注葡萄糖时胰岛素的分泌也减少,并认为挥发性麻醉药均有直接抑制胰岛素分泌的作用。为此,作者选用14只重17～20kg无特定病原体(specificpathogen-free)的雄猪作实验研究。 给动物肌注氯铵酮-阿托品后,穿刺耳静脉,注泮库溴铵,插气管导管吸N_2O-O_2,注氯铵酮维持麻醉,机械通气维持PaCO_2(4.6±0.6)kPa。穿刺颈动脉并置管供采血、测压,用肝素处理后将管外置备用。于4～7d后将动物分成清醒组、吸入七氟醚0.4MAC组和吸七氟醚1.0MAC组。每只猪可做1～2次试验,每次试验     

静吸复合麻醉下七氟醚与异氟醚对颅内压的影响

目的:在颅内顺应性正常神经外科病人,观察1.0 MAC七氟醚与异氟醚对颅内压的影响。方法:垂体瘤或颅咽管瘤手术病人16例,随机分为两组:A组为咪唑安定 芬太尼 1.0 MAC异氟醚;B组为咪唑安定 芬太尼 1.0 MAC七氟醚。选择L_(3～4)行蛛网膜下腔穿刺。麻醉诱导采用芬太尼-咪唑安定-阿曲库铵。插管后维持稳定30分开始吸入七氟醚(或异氟醚)。分别于麻醉前、吸入麻醉药前、达预定呼气末浓度30分内观察监测指标。结果:1.0 MAC七氟醚和异氟醚均可显著降低脑灌注压,异氟醚作用较强。吸入1.0 MAC七氟醚后颅内压首先呈显著性下降,15分后回复至基础水平。吸入1.0 MAC异氟醚后颅内压无显著性变化。结论:在颅内顺应性正常患者,1.0 MAC七氟醚和异氟醚均可安全用于神经外科麻醉。     

全麻中成人与小儿血乳酸的变化

本文比较全麻中成人与小儿血乳酸值的变化。方法:肝功、内分泌正常的择期手术病人,小儿、成人各10例。小儿以O_2-N_2O-七氟醚诱导,成人以硫喷妥钠、琥珀胆碱诱导,气管插管后人工呼吸,维持PetCO_230～35mmHg。两组均以N_2O-O_2-七氟醚维持麻醉。输液为林格氏液10ml·kg~(-1)·h~(-1)。分别于麻醉诱导后即刻及麻醉后60min测定血乳酸、血气、血糖。     

儿童七氟醚麻醉与异丙酚麻醉苏醒质量的对比

七氟醚无明显刺激味,在血和组织中溶解度低,药物排除快;而异丙酚则具有诱导迅速平稳,苏醒快而完全及术后并发症少的优点。故二者均适用于非住院小儿外科手术。但最近有报道七氟醚麻醉后激动和不安的发生率比氟烷高。作者为比较异丙酚与七氟醚麻醉后小儿的苏醒质量(quality of recovery),选择50名ASAⅠ～Ⅱ级择期做扁桃体摘除术儿童(3～10岁),随机接受异丙酚麻醉(P组,n=25,静注异丙酚3mg·kg~(-1)诱导,100～250μg·kg~(-1)·min~(-1)维持);七氟醚麻醉(S组,n=25,吸7vol％七氟醚-N_2O-O_2诱导和(2～3)vol％七氟醚-N_2O-O_2维持)。两组均在静注阿芬太尼20μg·kg~(-1)和阿曲库铵0.5mg·kg~(-1)后气管插管,控制呼吸维持     

硫喷妥钠-安定诱导、N_2O-异氟醚维持麻醉对二尖瓣直视手术病人血流动力学的影响

对21例采用小剂量硫喷妥钠-安定诱导、N_2O-异氟醚吸入维持的二尖瓣直视手术病人进行了血流动力学测定。组Ⅰ(7例)术前临床心功能为Ⅱ级,组Ⅱ(14例)为Ⅲ～Ⅳ级。结果:①诱导后两组病人的CI及SI均减低,组Ⅱ尚伴有MAP及MPAP降低。气管插管后组Ⅰ的CI及MAP短暂增加。②劈胸骨后组Ⅱ的PVR明显增加。③主动脉及腔静脉插转流管后组ⅡMPAP、PVR、SVR及MAP均明显减低,但CI及SI较诱导后有所增加,并接近术前值。结果提示:对于心功Ⅱ级的二尖瓣病变病人采用小剂量硫喷妥钠诱导应属可取;但对心功Ⅲ～Ⅳ级病人应格外慎重。心功差者采用吸入1％以下异氟醚维持亦称安全,尤适用于伴有低排高阻者。     

酶诱导对七氟醚肝毒性的影响

目的:观察用异烟肼预处理后大鼠吸入七氟醚后血清谷丙转氨酶(SGPT)及肝病理学的变化,以研究酶诱导对七氟醚肝毒性的影响。方法:将40只月龄2～3月的SD大鼠随机分为对照组(C组),异烟肼组(Ⅰ组),酶诱导的七氟醚组(SI组),未有酶诱导的七氟醚组(S)组.Ⅰ组和SI组每天用异烟肼预处理25mg·kg~(-1)腹腔注射,持续三天。SI组和S组吸0.5MAC七氟醚3小时,C组和Ⅰ组吸O~2和空气混合气体。结果:SI组SGPT浓度(162.0±25.3)明显高于C组(115.8±41.8)、Ⅰ组(121.6±42.9)和S组(126.2±26.2)(P<0.05),且该组肝细胞疏松化程度较其它各组严重。结论:酶诱导有增加七氟醚肝毒性的可能。     

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.     

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.     

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.     

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.     

The analgesic effect of racemic ketamine in patients with chronic ischemic pain due to lower extremity arteriosclerosis obliterans

Background : Ketamine in sub-dissociative doses has been shown to have analgesic and phantom-Limb pain, where conventional treatment has often failed. Chronic ischemic pain due to lower extremity arteriosclerosis obliterans often responds poorly to analgesics, and the pain-generating mechanisms are not well understood.
Methods : Eight patients with rest pain in the lower extremity due to arteriosclerosis obliterans were given sub-dissociative doses of 0.15, 0.30, or 0.45 mg/kg racemic ketamine and morphine 10 mg as a 5-min infusion on four separate days in a cross-over, double-blind, randomised protocol. Plasma levels of (S)- and (R)-ketamine and their nor-metabolites were analysed with an enantioselective high-performance liquid chromatography (HPLC) method. Pain levels were evaluated with a visual analogue scale (VAS).
Results : Individual pain levels were highly variable during and after all the infusions but the pooled pain levels showed a dose-dependent analgesic effect of ketamine with a transient but complete pain relief in all patients at the highest dose (0.45 mg/ kg). Side-effects, mainly disturbed cognition and perception, were pronounced and dose-dependent. Morphine 10 mg had an analgesic peak at 20 min and 5/8 patients had complete pain relief. The remaining 3 patients also had high baseline pain scores, indicating a higher analgesic potency for the 0.30 and 0.45 mg/ kg ketamine doses than for morphine 10 mg.
Conclusion : We have demonstrated a potent dose-dependent analgesic effect of racemic ketamine in clinical ischemic pain. Due to a narrow therapeutic window, this analgesic effect is probably best utilised in combination with other analgesics.