血浆置换联合连续性血液滤过治疗急性呼吸窘迫综合征的临床观察

目的 研究血浆置换(plasma exclrange,PE)联合连续性静脉-静脉血液滤过(continuous venous-venous hemofiltIlation,CVVH)治疗急性呼吸窘迫综合征(acute respitatory distresssyndrome ARDS)的疗效.方法 20例急性呼吸窘迫综合征患者除经内科常规治疗外,行PE联合CVVH,连续测定心率、平均动脉压(MAP)、中心静脉压(CVP),血pH、动脉血氧分压(PaO2)、动脉血二氧化碳分压(PaCO2),氧合指数(PaO2/FiO2)、肺动态顺应性(Cdyn)、气道阻力(Raw),同时抽取静脉血测定C反应蛋白(C-reactive protein,CRP)的浓度.并进行ICU监护的结果记录以APAcHE Ⅱ评分及SIRS评分判断患者病情的变化.结果 治疗过程中患者血流动力学稳定,血浆置换前后及CVVH治疗前与治疗后相比心率(HR)、平均动脉压(MAP)、中心静脉压(CVP)、血PH、动脉血氧分压(PaO2)、动脉血二氧化碳分压(PaCO2)、氧合指数(PaO2/FiO2)、肺动态顺应性(Cdyn)明显升高,气道阻力(Raw)明显下降(P＜0.05),血浆置换后C反应蛋白浓度明显下降(P＜0.05),CVVH治疗前与治疗后相比APACHE Ⅱ评分及SIRS评分差异显著(P＜0.05).结论 PE联合CVVH治疗可显著改善急性呼吸窘迫综合征患者的临床症状,有效改善急性呼吸窘迫综合征的预后.     

不同模式血液净化治疗脓毒症的临床研究

目的 探讨高容量血液滤过(HVHF)和连续性静脉静脉滤过透析(CVVHDF)两种模式治疗脓毒症的效果.方法 18例脓毒症患者按随机数字表法分为两组,A组(HVHF模式,10例)置换液流速4L/h;B组(CVVHDF模式.8例)置换液流速2L/h,透析液流速2L/h.于治疗oh、12h和24 h测定血清和超滤液中自细胞介素6(IL-6)、白细胞介素10(IL-10)的浓度.同时观察两组患者治疗前、后体温、心率、平均动脉压、氧合指数、急性生理学和慢性健康状况评分(APACHEⅡ评分)、尿素氮和肌酐的变化.结果 A、B两组患者治疗后体温较治疗前明显下降(P＜O.01);A组患者治疗后氧合指数较治疗前明显升高(P＜0.05);A组患者氧合改善较B组更明显(P＜0.05);A组患者治疗后APACHEⅡ评分较治疗前明显降低(P＜0.01).B组患者APACHEⅡ评分治疗后较治疗前降低(P＜0.05);A组患者APACHEⅡ评分的降低较B组更明显(P＜0.01);两组患者心率、平均动脉压、尿素氮、肌酐指标治疗前、后比较差异无统计学意义(P＞0.05).A组患者血清IL-6浓度治疗后较治疗前明显降低(P＜0.01);B组患者血清IL-6浓度治疗前较治疗后明显降低(P＜0.05);A组患者血清IL-6浓度降低程度较B组更明显(P＜0.05);A、B组患者血清IL-10浓度治疗后较治疗前有降低趋势,但差异无统计学意义(P＞0.05);A、B组患者超滤液中均检测到IL-6、IL-10.结论 HVHF模式较LWVHDF模式更能降低机体基础代谢率及耗氧量.增加机体组织的氧供,改善脓毒症患者脏器功能的指标;HVHF、CVVHDF‘两种模式均能通过超滤清除炎性介质,HVHF模式清除效果优于CVVHDF模式.     

高容量血液滤过治疗多器官功能障碍综合征的分析

目的研究高容量血液滤过 (HVHF)在多器官功能障碍综合征 (MODS)治疗中的作用。方法 19例MODS患者 ,随机选择 10例行HVHF ,另 9例行常规连续性静脉 静脉血液滤过 (CVVH)。于治疗前和治疗开始后 2、4、8h动脉采血 ,检测血气、血肌酐 (Scr)、尿素氮 (BUN)、肿瘤坏死因子(TNFα)、白细胞介素 1(IL 1β)、白细胞介素 6 (IL 6 )的变化。 结果HVHF组与CVVH组于治疗开始后4h血Scr、BUN均显著下降 ,肾功能改善。HVHF组血TNFα、IL 1β、IL 6治疗前分别为 ( 1795± 5 0 6 )ng/L、( 96 4± 185 )ng/L、( 1332± 4 15 )ng/L ,治疗开始后 4h为 ( 12 6 5± 397)ng/L、( 5 11± 12 4 )ng/L、( 72 6±2 4 3)ng/L ,差异有显著意义 ,P <0 0 5。CVVH组血TNFα治疗前为 ( 1799± 5 11)ng/L ,治疗开始后 4h为 ( 132 7± 4 2 1)ng/L ,差异有显著意义 ,P <0 0 5。HVHF组死亡 3例 ( 3/ 10 ) ,CVVH组死亡 5例 ( 5 / 9) ,差异有显著意义 ,P <0 0 5。结论HVHF可通过对流和AN6 9膜的吸附作用清除大量炎症介质 ,改善MODS患者的预后     

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目的　观察持续高流量血液滤过 (HVHF)对重症急性胰腺炎 (SAP)伴多器官功能障碍综合征(MODS)的治疗作用。方法　 1997～ 2 0 0 2年 2 8例SAP伴MODS接受了HVHF治疗。APACHEⅡ评分为(14 36± 3 96 )分 ,BalthazarCT评分为 (8 5± 1 4 )分。从发病到开始HVHF时间 (6 0± 6 1)d ,HVHF治疗时间为 (4 0 4± 3 99)d。置换液以前稀释方式输入 ,流量为 4 0 0 0mL/h ,血流量 2 5 0～ 30 0mL/min ,连续 2 4h不间断。滤器为AN6 9膜 ,面积 1 2m2 ,每 2 4h更换 1次。采用低分子肝素抗凝。结果　 2 8例病人中 ,2 0例治愈出院 ,2例因经济原因放弃治疗 ,6例死亡 (2 1 4 % )。HVHF后体温、心率和呼吸频率显著降低 ;APACHEⅡ评分显著下降(14 4± 3 9vs 9 9± 4 3,P <0 0 1) ;动脉血氧分压显著提高 (6 8 5± 19 5vs 91 9± 2 5 0 ,P <0 0 1)。所有病人均良好耐受HVHF治疗 ,HVHF过程中血流动力学稳定 ,未发现明显的副作用。结论　对SAP伴MODS的病人 ,HVHF明显改善体温、心率、呼吸频率、APACHEⅡ评分和动脉血氧分压。HVHF过程中血流动力学稳定 ,可能成为重要的辅助治疗措施。     

连续性静脉-静脉血液滤过对尿毒症脑病的疗效观察

目的:探讨连续性静脉-静脉血液滤过(CVVH)对慢性肾衰竭(CRF)合并尿毒症脑病(UE)患者的血液动力学、电解质、溶质清除方面的影响,并评价其治疗效果。方法:30例次CRF并发UE的患者,接受CVVH治疗。观察治疗前和治疗中、治疗后患者的心率、平均动脉压(MAP)以及意识情况和患者的APACHEⅡ评分、Glasgow评分;测定治疗前、后的肾功能、电解质及血浆渗透压。结果:(1)CVVH治疗前后MAP、心率及渗透压变化无统计学差异(P>0.05);(2)CVVH治疗后意识明显改善,尿毒症症状明显缓解;(3)CVVH治疗后患者APACHEⅡ评分较治疗前有明显降低的趋势,Glasgow评分明显好转(P<0.05);(4)CVVH治疗后BUN、Scr清除好,电解质、酸碱紊乱得以纠正(P<0.05)。结论:CVVH具有稳定的血流动力学,缓慢、持续、稳定清除尿毒症毒素和纠正电解质和酸碱失衡,对心血管系统和血脑屏障的干扰小,病人的耐受性好,有助于尿毒症脑病的治疗。     

Th1/Th2平衡在高容量血液滤过防治多脏器功能衰竭中的变化及意义

目的探讨多脏器功能衰竭（MODS）发病机制及高容量血液滤过（HVHF）防治MODS的依据。方法采用2次打击法建立猪MODS模型，酶联免疫吸附试验（ELISA）法检测血清干扰素（IFN）-γ和白细胞介素（IL）-4含量变化；逆转录-聚合酶链反应（RT—PCR）法测定脾脏IFN-γ、IL-4mRNA水平及辅助T细胞特异性转录因子T-bet和GATA-3mRNA的含量变化。结果HVHF组MODS发生率为20％，显著低于MODS组88．9％（P〈0．01）；血清IFN-γ和IL-4浓度显著低于MODS组（P〈0．05），处死前IFN-γ／IL-4比值明显高于MODS组（P〈0．01）；脾脏IFN-γ和IL-4 mRNA表达量较MODS组明显下降（P〈0．05），IFN-γ/IL-4 mRNA比值明显高于MODS组（P〈0．05）；脾脏GATA3mRNA表达量低于MODS组（P〈0．01），T—bet mRNA表达量下降，差异无统计学意义（P〉0．05），T-bet／GATA3比值显著高于MODS组（P〈0．01）。结论Th1向Th2漂移可能是MODS发生的本质原因之一，HVHF能够在一定程度上遏止Th1向Th2漂移的发生。     

血浆DNA浓度评估脓毒症患者预后的准确性

目的 探讨血浆DNA浓度评估脓毒症患者预后的准确性.方法 随机选取160例脓毒症患者作为脓毒症组(SE组),选取109例非脓毒症患者作为对照组(C组).入院时抽取外周静脉血样,采用PCR法、酶联免疫吸附试验法分别测定血浆DNA浓度和C反应蛋白(CRP)浓度,记录入院24h内情况最差时急性生理与慢性健康评估Ⅱ评分(APACHEⅡ评分)和序贯器官衰竭评分(SOFA评分).根据存活情况将SE组患者分为存活组(n=103)和死亡组(n=57).结果 与C组比较,SE组血浆DNA浓度、CRP浓度、APACHEⅡ评分、SOFA评分升高(P＜0.05);与存活组比较,死亡组血浆DNA浓度、CRP浓度、APACHEⅡ评分、SOFA评分升高(P＜0.05).血浆DNA浓度、SOFA评分、APACHEⅡ评分曲线下面积分别为0.81(95％CI,0.74～0.88)、0.72(95％ CI,0.63 ～ 0.82)和0.68(95％CI,0.60～0.77).结论 血浆DNA浓度可准确评估脓毒症患者预后,与CRP浓度、APACHEⅡ评分、SOFA评分比较,血浆DNA浓度预测脓毒症患者的预后准确性更高.     

常用风险评估系统在心脏手术后风险评估中的应用

目的 比较多器官衰竭评分系统(MODS)、序贯器官衰竭评分系统(SOFA)、急性生理及慢性健康评分系统(APACHE)Ⅱ、APACHE Ⅲ对患者心脏手术后风险评估的价值,为重症患者的治疗及预测预后提供依据. 方法 自2007年10月至2008年4月,北京安贞医院心脏外科监护室收治18岁以上心脏手术后患者共1 935例,男1 050例,女885例;年龄18～86岁,平均年龄53.96岁.病种包括冠心病、心瓣膜病、先天性心脏病、动脉瘤、心房颤动、心包疾病、肺动脉栓塞等.采用MODS、SOFA、APACHE Ⅱ、APACHE Ⅲ系统进行评分,分别计算各评分系统的手术当天分值、3 d内最大分值、最大分值、第3 d与第1 d的差值,再计算各评分系统不同时段的ROC曲线下面积,并进行Hosmer-Lemeshow拟合优度检验. 结果 围术期死亡47例,死亡率2.43%,主要死于循环功能、呼吸功能、肾功能、肝功能衰竭和神经系统病变.MODS评分系统的手术当天分值、最大MODS值、手术3 d内最大MODS值和手术后第3 d与第1 d的MODS分值差ROC曲线下面积分别为0.747,0.901,0.892,0.786;χ2值分别为4.712, 5.905, 5.384, 13.215.SOFA系统ROC曲线下面积分别为0.736,0.891,0.880,0.798;χ2值分别为8.673, 3.189, 3.111, 14.225.APACHE Ⅱ系统ROC曲线下面积分别为0.699, 0.848, 0.827, 0.562;χ2值分别为15.688, 10.132,8.061, 42.253.APACHE Ⅲ系统ROC曲线下面积分别为0.721, 0.872,0.869, 0.587;χ2值分别为13.608,11.196, 19.310, 47.576.MODS和SOFA评分系统的ROC曲线下面积均大于APACHE Ⅱ或APACHE Ⅲ评分系统的相应值(P<0.05);APACHE Ⅱ评分系统的ROC曲线下面积均小于APACHE Ⅲ评分系统的相应值(P<0.05). 结论 MODS、SOFA、APACHE Ⅱ、APACHE Ⅲ系统都可用于心脏外科手术后患者的风险评估,但MODS和SOFA系统对死亡的风险评估优于APACHE Ⅱ、APACHE Ⅲ系统.在心脏外科中,可以用简单的MODS和SOFA系统替代复杂的APACHE Ⅱ、APACHE Ⅲ系统.     

连续性静脉-静脉血液滤过对多器官功能障碍综合征患者血浆细胞因子水平的影响

目的观察连续性静脉．静脉血液滤过（CVVH）对多器官功能障碍综合征（MODS）患者血浆细胞因子TNF-α、IL-1、IL-6、IL-8水平的影响。方法选择MODS患者22例,行CVVH治疗,取治疗前后动脉血做血气分析,取静脉血和滤出液检测有关细胞因子水平。在开始行CVVH前及CVVH治疗后1h．4h、8h分别测量心率和平均动脉压。结果22例患者CVVH治疗后血浆TNF-α、IL-1水平明显下降（P〈0．05）。超滤液中未检出TNF-α,但有较高浓度的IL-1、IL-6和IL-8。与CVVH前比较,患者心率显著下降（P〈0．05）,平均动脉压和氧合指数明显升高（P〈0．05）。CVVH治疗后患者的APACHEⅡ评分显著下降,其下降与置换液速度呈正相关。死亡患者置换液速度与存活患者置换液速度有显著差异（P〈0．05）。能够被CVVH有效清除的细胞因子与置换液速度呈正相关（P〈0．05）。结论CVVH可清除MODS患者血浆中部分细胞因子,并可改善患者血流动力学及氧合功能。加大置换液速度能更好地清除外周血细胞因子,并改善预后。     

不同剂量血液滤过对内毒素休克猪生存时间和细胞因子水平的影响

目的 探讨不同剂量连续性血液滤过（CVVH）对细胞因子的清除作用以及对血浆细胞因子水平的影响。 方法 采用静脉注射内毒素（E.coli O111: B4,15.7 μg/kg）的方法诱导内毒素休克猪模型。将内毒素休克猪按随机数字表法分为对照组(n=6)、 CVVH组 (n=6,前稀释法,等于后稀释法的45 ml·kg-1·h-1）和高容量血液滤过（HVHF）组 (n=6,前稀释法,等于后稀释法的70 ml·kg-1·h-1）。于造模前（基线）、成模时（T0）,成模后1 h（T1）、6 h（T6）、12 h（T12）、24 h（T24）分别测定血浆肿瘤坏死因子α（TNF-α）、白细胞介素（IL）6、IL-10和IL-18水平。 结果 对照组动物平均生存时间为（15.4±5.2） h;CVVH 组为(21.4±7.1) h;HVHF组为（22.4±6.7） h,CVVH组和HVHF组的生存时间显著高于对照组（均P < 0.05）。3组动物的心率（HR）、平均动脉压（MAP）、中心静脉压（CVP）和心排出量（CO）之间差异无统计学意义（P > 0.05）。内毒素休克猪成模后出现BUN和Scr的进行性升高,两治疗组的BUN和Scr水平显著低于对照组（P < 0.05）,但两者之间差异无统计学意义（P > 0.05）。对照组TNF-α和IL-6水平在T1时达高峰,IL-10水平在T0时最高,随后不断下降。IL-18水平在成模后上升,后无明显变化。CVVH组血浆IL-10（T6、T12、T24）水平低于对照组（P < 0.05）。HVHF组TNF-α（T6）和IL-10（T6、T12、T24）水平低于对照组和CVVH组（P < 0.05）,3组的IL-6和IL-18水平差异无统计学意义,IL-6（T6、T12）水平和动物生存时间呈负相关（P < 0.05）。 结论 CVVH和HVHF治疗均能显著延长内毒素休克猪的生存时间。CVVH能有效清除IL-10;HVHF治疗能清除TNF-α和IL-10;但CVVH和HVHF对IL-6和IL-18水平无明显影响;CVVH和HVHF均能有效清除BUN和Scr。IL-6水平是预测内毒素休克预后的独立指标。     

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.     

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.     

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.     

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.     

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.     

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.     

Systemic analgesia adapted to the children's condition

A concept of balanced analgesia using nonsteroidal anti-inflammatory drugs (NSAIDs), paracetamol (acetaminophen), opioids, and corticosteroids can also be used in patients with pre-existing illnesses. NSAIDs are the most effective treatment for acute pain of moderate intensity in children; however, these drugs should be avoided in patients at increased risk for serious side effects, e.g. patients with renal impairment, bleeding tendency, or extreme prematurity. NSAIDs can be given with minimal risks to the younger child with mild to moderate asthma, and, in these patients, the use of steroids can be encouraged; in addition to their antiemetic and analgesic action, a beneficial effect on asthma symptoms can be expected. In the non-intubated child with cerebral trauma, exaggerated sedation caused by opioids and increased bleeding tendency caused by NSAIDs must be avoided. In neonates and small infants, the oral administration of sucrose or glucose is helpful to minimize pain reaction during short uncomfortable interventions.