不同剂量瘦素对大鼠机械通气肺损伤的影响

目的评价不同剂量瘦素对大鼠机械通气肺损伤的影响。方法健康清洁级SD雄性大鼠48只,6～8周龄,采用随机数字表法分为四组:气管切开保留自主呼吸的假手术组(A组)、机械通气模型组(B组)、瘦素10μg/kg组(C组)和瘦素50μg/kg组(D组),每组12只。采用10%水合氯醛3.5 ml/kg麻醉大鼠,疼痛反射消失后C组腹腔注射瘦素10μg/kg,D组腹腔注射瘦素50μg/kg,A、B组腹腔注射等容量生理盐水,注射后即刻进行气管切开,插管机械通气。A组气管插管后保留自主呼吸,B、C、D组机械通气建立VILI模型,参数设置:V_T 20 ml/kg,RR 80次/分,I∶E 1∶1,FiO_2 21%,PEEP 0 mmHg,通气时间4 h。分别于基础状态、通气结束时抽取股动脉血进行血气分析。通气结束后放血处死大鼠,在4℃下取肺组织并收集支气管肺泡灌洗液(bronchoalveolar lavage fluid, BALF),光镜下进行中性粒细胞计数,采用ELISA法测定TNF-α、IL-6、IL-1β浓度;取肺组织称重,计算肺湿干重比(W/D);观察肺组织病理改变并进行病理评分;采用Western blot检测肺组织研磨液中NF-κB p65含量。结果与A组比较,B、C、D组W/D、肺损伤评分、BALF中性粒细胞计数、TNF-α、IL-6、IL-1β浓度及肺组织NF-κB p65含量明显升高(P0.01)。与B组比较,C、D组BALF中性粒细胞计数、TNF-α、IL-6、IL-1β浓度及肺组织肺损伤评分、NF-κB p65含量明显降低(P0.05)。与C组比较,D组BALF中性粒细胞计数、TNF-α、IL-6、IL-1β浓度及肺组织肺损伤评分、NF-κB p65含量明显降低(P0.05)。结论瘦素可降低大鼠机械通气肺损伤中炎性因子的表达水平,减轻肺损伤,50μg/kg较10μg/kg作用明显。     

七氟醚介导腺苷A3受体通路减轻大鼠机械通气肺损伤

目的探讨腺苷A3受体(A_3AR)在七氟醚减轻大鼠机械通气肺损伤(VILI)中的作用及其机制。方法 SPF级健康雄性成年大鼠40只,体重200~250g,随机分为五组:假通气组(Sham组),模型对照组(CON组),七氟醚处理组(SEV组),七氟醚联合A_3AR抑制剂处理组(SM组),A_3AR抑制剂处理组(MRS组),每组8只。除Sham组不进行通气外,其他四组均在麻醉气管插管后行机械通气(V_T 12ml/kg),持续正压通气6h,建立大鼠VILI模型。Sham组:氯胺酮麻醉后直接处死;CON组:氯胺酮维持麻醉状态;SEV组:2%七氟醚维持麻醉;SM组:机械通气开始前30min腹腔注射MRS-1191 1mg/kg,2%七氟醚维持麻醉;MRS组:机械通气开始前30min腹腔注射MRS-1191 1mg/kg,氯胺酮维持麻醉。实验结束后处死大鼠,收集支气管肺泡灌洗液(BALF)和肺组织标本。采用Western blot法检测肺组织A_3AR、gp91~(phox)蛋白含量。检测BALF中炎性因子TNF-α、IL-1β浓度。DHE染色荧光检测肺组织活性氧(ROS)活性。观察肺组织病理学变化,并进行肺损伤评分。结果与SEV组比较,CON组、SM组和MRS组TNF-α、IL-β浓度明显升高(P0.05);与SM组比较,CON组与MRS组TNF-α、IL-β浓度明显升高(P0.05)。与Sham组比较,CON组、SEV组、SM组和MRS组A_3R、gp91~(phox)蛋白含量明显升高,CON组、SM组和MRS组ROS活性明显增强,肺损伤评分明显升高(P0.05);与CON组比较,SEV组和SM组A_3AR蛋白含量明显升高,SEV组gp91~(phox)蛋白含量、ROS活性和肺损伤评分明显降低(P0.05);与SEV组比较,SM组A_3AR蛋白含量明显降低,gp91~(phox)蛋白含量明显升高,SM组和MRS组ROS活性明显增强,肺损伤评分明显升高(P0.05)。结论七氟醚可以减轻机械通气诱发的肺损伤,其作用机制是通过A_3AR抑制肺脏氧化应激和炎症反应起效的。     

电针通过NLRP3/caspase-1通路介导的细胞焦亡途径减轻脓毒症大鼠急性肺损伤

目的:观察电针足三里穴和肺俞穴是否通过NLRP3/caspase-1通路介导的细胞焦亡途径减轻脓毒症诱导的大鼠急性肺损伤。方法:成年健康雄性SD大鼠30只,采用随机数字表法分为5组:对照组、模型组、电针组、电针+NLRP3激活剂组、非经非穴电针组,每组6只。采用盲肠结扎穿孔法建立脓毒症模型。电针组选取双侧足三里穴和肺俞穴给予疏密波电针刺激(模型制备前5 d每天进行1次,模型制备过程中每6 h进行1次,30 min/次);非经非穴电针组以相同的参数电针刺激足三里穴和肺俞穴旁开5 mm非经非穴处。于模型制备前30 min电针+NLRP3激活剂组腹腔注射100 mg/kg尼日利亚菌素钠盐。建模后24 h时处死大鼠取肺组织,计算肺湿重/干重(W/D)比值,观察病理学结果并行肺损伤评分;采用ELISA法测定肺组织白细胞介素(IL)-1β、IL-18含量;采用Western blot法检测肺组织核苷酸结合寡聚化结构域样受体蛋白3(NLRP3)、凋亡相关斑点样蛋白(ASC)、裂解的半胱氨酰天冬氨酸特异性蛋白酶-1(cleaved-Caspase-1)、N端消皮素-D(gasdermin D,GSDMD-N)蛋白的表达水平。结果:与对照组比较,模型组、电针组、电针+NLRP3激活剂组和非经非穴电针组肺损伤评分、W/D比值、IL-1β含量及IL-18含量均升高,肺组织NLRP3、ASC、cleaved-Caspase-1及GSDMD-N蛋白表达均上调,差异有统计学意义(P＜0.05);与模型组比较,电针组肺损伤评分、W/D比值、IL-1β含量及IL-18含量均降低,肺组织NLRP3、ASC、cleaved-Caspase-1及GSDMD-N蛋白表达均下调,差异有统计学意义(P＜0.05);与电针组比较,电针+NLRP3激活剂组肺损伤评分、W/D比值、IL-1β含量及IL-18含量均升高,肺组织NLRP3、ASC、cleaved-Caspase-1及GSDMD-N蛋白表达均上调,差异有统计学意义(P＜0.05)。结论:电针刺激足三里穴和肺俞穴减轻大鼠脓毒症急性肺损伤的机制可能与抑制NLRP3/caspase-1通路介导的经典细胞焦亡途径有关。     

Rho/Rock 信号通路在大鼠呼吸机相关性肺损伤中的作用

目的评价Rho/Rock信号通路在大鼠呼吸机相关性肺损伤(ventilator-induced lung injury,VILI)中的作用。方法选择健康雄性SD大鼠96只,12~15周龄,体重300~350g,采用随机数字表法将大鼠随机分为四组:空白对照组(C组)、Rho激酶抑制药法舒地尔组(F组)、高潮气量组(H组)和高潮气量+Rho激酶抑制药法舒地尔组(HF组),每组24只。C组和F组不行机械通气,H组和HF组行高潮气量40ml/kg机械通气4h。F组和HF组在机械通气前1h给予腹腔注射法舒地尔10mg/kg。分别于通气前(T0)、通气后4h(T1)、8h(T2)和24h(T3)每组随机取6只大鼠,采集血样,测定血清TNF-α、IL-6及IL-10浓度;采血结束后处死大鼠,收集支气管肺泡灌洗液(BALF),采用考马斯亮兰法检测BALF总蛋白;测定肺组织湿/干重比(W/D);光镜下行肺组织病理学损伤评分;采用分光光度法检测肺组织髓过氧化物酶(MPO)活性;采用Western blot和RT-PCR法分别检测肺组织RhoA、Rock2蛋白含量和mRNA表达水平。结果与C组比较,T1~T3时H组和HF组大鼠血清TNF-α、IL-6及IL-10浓度、BALF总蛋白含量、肺组织W/D、病理学损伤评分、MPO活性、RhoA、Rock2蛋白含量和mRNA表达水平明显升高(P0.05);与H组比较,T1~T3时HF组大鼠血清TNF-α、IL-6浓度、BALF总蛋白含量、肺组织W/D、病理学损伤评分、MPO活性、RhoA、Rock2蛋白含量和mRNA表达水平明显下降,血清IL-10浓度明显升高(P0.05)。结论Rho激酶抑制药法舒地尔可减轻大鼠呼吸机相关性肺损伤,其机制可能与其抑制Rho/Rock信号通路,降低肺组织内炎性反应有关。     

组织蛋白酶B在大鼠呼吸机相关性肺损伤中的作用：与NLRP3炎症小体的关系

目的评价组织蛋白酶B(CTSB)在大鼠呼吸机相关性肺损伤(VILI)中的作用及其与NOD样受体热蛋白结构域相关蛋白3(NLRP3)炎症小体的关系。方法 SPF级健康雄性SD大鼠36只, 6～8周龄, 体重220～300 g, 采用随机数字表法分为3组(n=12):对照组(C组)、VILI组(V组)和VILI+CA074-me组(Me组)。C组和V组大鼠气管插管前1 h腹腔注射等量生理盐水, Me组腹腔注射CA074-me 5 mg/kg。C组自主呼吸4 h, V组和Me组行机械通气4 h, 通气参数:VT 20 ml/kg, 通气频率80次/min, FiO2 21%, PEEP 0 cmH2O。气管插管前和自主呼吸或通气结束后采集股动脉血行动脉血气分析, 记录PaO2, 随后处死大鼠, 收集支气管肺泡灌洗液(BALF)和取肺组织, 确定肺组织湿重/干重(W/D)比值, HE染色法观察病理学结果并进行肺损伤评分, 采用ELISA法检测BALF及血清IL-1β和IL-18浓度。采用qRT-PCR法检测肺组织CTSB、NLRP3、凋亡相关斑点样蛋白(ASC)和caspase-1的mRNA表...     

白细胞介素-17A在小鼠机械通气相关性肺损伤中的作用

目的探讨白细胞介素-17A(IL-17A)在小鼠机械通气相关性肺损伤中的作用。方法SPF级雄性C57BL/6小鼠40只,2～3月龄,体重25～30 g。将小鼠随机分为四组:假手术组(S组),假手术+IL-17A单克隆抗体组(SA组),机械通气肺损伤模型组(V组),机械通气损伤模型+IL-17A单克隆抗体组(VA组),每组10只。S组和SA组仅行气管切开保留自主呼吸。V组和VA组机械通气4 h。SA组和VA组在气管切开后于腹腔注射IL-17A单克隆抗体(10μg, 0.1 ml),S组和V组于腹腔注射等体积的抗体稀释液。机械通气结束时处死小鼠取肺组织,采用ELISA法检测支气管肺泡灌洗液(BALF)中肿瘤坏死因子-α(TNF-α)和白细胞介素-6(IL-6)浓度,测定肺组织湿干重比值(W/D),采用TUNEL染色法测定肺组织细胞凋亡指数,采用Western Blot法检测肺组织IL-17A和cleaved-caspase-3蛋白含量,采用HE染色法观察肺组织病理学结果并进行肺损伤评分。结果与S组比较,V组和VA组BALF中TNF-α和IL-6浓度、W/D、细胞凋亡指数、肺组织IL-17A和cleaved-caspase-3蛋白含量、肺损伤评分均明显升高(P0.05),肺组织病理学改变加重。与V组比较,VA组BALF中TNF-α和IL-6浓度、W/D、细胞凋亡指数、肺组织IL-17A和cleaved-caspase-3蛋白含量、肺损伤评分均明显降低(P0.05),肺组织病理学损伤改善。S组和SA组各项指标差异无统计学意义。结论大潮气量机械通气可导致机械通气相关性肺损伤,IL-17A介导了机械通气相关性肺损伤的发生、发展过程,可能与IL-17A加重炎症反应和诱导细胞凋亡有关。阻断IL-17A可通过减轻肺组织炎症反应、减少细胞凋亡改善机械通气相关性肺损伤。     

七氟醚减轻大鼠呼吸机相关性肺损伤

目的 探讨七氟醚对大鼠呼吸机相关性肺损伤(VILI)的影响并探讨其可能机制。方法 健康SPF级雄性SD大鼠36只,6～8周龄,体重220～280 g。随机分为三组：对照组(C组)、VILI组(V组)和七氟醚组(S组),每组12只。大鼠给予1%戊巴比妥钠40 mg/kg麻醉后行气管切开插管术,C组自主呼吸4 h, V组和S组插管后机械通气4 h, S组机械通气期间吸入2%七氟醚4 h。通气参数：V_T 20 ml/kg, RR 80次/分,I∶E 1∶1,FiO₂ 21%,PEEP 0 cmH₂O。机械通气结束时采集股动脉血测定PaO₂。处死大鼠,取肺组织和支气管肺泡灌洗液(BALF),计算肺组织湿/干重比值(W/D),采用ELISA法检测BALF中白细胞介素(IL)-1β、IL-18浓度,二氯荧光黄双乙酸盐法检测BALF中肺泡巨噬细胞活性氧(ROS)水平,Western blot法及qRT-PCR法检测肺组织NF-E2相关因子2(Nrf2)、NLRP3、凋亡相关斑点样蛋白(ASC)、caspase-1...     

半乳糖凝集素-1预处理对机械通气相关性肺损伤小鼠的影响

目的 探讨半乳糖凝集素-1(Galectin-1)预处理对机械通气相关性肺损伤(VILI)小鼠的影响。方法 选择清洁级健康雄性C57BL/6小鼠30只,6～8周龄,体重22～30 g。采用随机数字表法将小鼠分为三组：对照组(C组)、VILI组(V组)和Galectin-1+VILI组(G组),每组10只。C组气管插管后保持自主呼吸4 h, V组和G组气管插管后机械通气4 h。气管插管前1 h C组和V组腹腔注射生理盐水0.75 ml, G组腹腔注射Galectin-1 3μg。于气管插管前即刻、自主呼吸或机械通气结束时采集动脉血检测PaO₂,后处死小鼠,收集肺泡支气管灌洗液(BALF),采用ELISA法检测BALF中IL-1β和IL-18浓度。取肺组织测定湿/干重比(W/D),采用qRT-PCR法检测肺组织GSDMD、caspase-1和caspase-11 mRNA表达量,Western blot法检测肺组织GSDMD、caspase-1和caspase-11蛋白含量,HE染色法观察病理改变并行肺损伤评分。结果 与C组比较,V组和G组机械通气结束时PaO     

黄芪甲苷预处理对大鼠肠缺血再灌注所致肺损伤的影响及其机制

目的:探讨黄芪甲苷(AS-Ⅳ)预处理对大鼠肠缺血再灌注所致肺损伤的影响及其相关机制。方法:将45只成年雄性SD大鼠随机均分为假手术(sham)组、肠缺血再灌注(I/R)组、AS-Ⅳ预处理(AS-Ⅳ)组。I/R组和AS-Ⅳ组通过夹闭肠系膜上动脉(SMA)60 min后再灌注120 min以建立I/R模型，sham组仅进行SMA暴露处理。AS-Ⅳ组于模型制备前60 min给予AS-Ⅳ(60 mg/kg)灌胃，sham组和I/R组在相同时间点用等体积的生理盐水灌胃。于再灌注120 min时取肺组织，采用HE染色法观察病理学变化，测定肺组织湿/干(W/D)比值和支气管肺泡灌洗液(BALF)/血清中分子量为4 kDa的FITC标记右旋糖酐(FITC-dextran 4 kDa, FD4)比值，并用ELISA法测定肺组织中白细胞介素(IL)-1β和IL-18水平，Western blotting法检测肺组织中NLRP3、ASC和caspase-1表达水平。结果:与sham组比较，I/R组肺组织病理学损伤评分、肺组织W/D比值和BALF/血清FD4比值升高，IL-1β和IL-18水平升高，NLRP3、ASC和caspase-1的表达水平升高(P<0.05)；与I/R组比较，AS-Ⅳ组肺脏组织病理学损伤评分、肺组织W/D比值和BALF/血清FD4比值降低，IL-1β和IL-18水平降低，NLRP3、ASC和caspase-1的表达水平降低(P<0.05)。结论:AS-Ⅳ预处理能够显著改善大鼠肠I/R所致的肺损伤，其机制可能与下调NLRP3炎症小体活化水平，减少细胞因子释放，从而减轻肺部组织炎症反应有关。     

Clara细胞分泌蛋白对兔单肺通气肺损伤的保护作用

目的 观察Clara细胞分泌蛋白(CCSP)对兔单肺通气肺损伤的保护作用.方法 30只新西兰大白兔随机均分为三组:双肺通气3 h组(Ⅰ组);单肺通气2 h,随后双肺通气1 h组(Ⅱ组);单肺通气Clara细胞剥除组(Ⅲ组)(通气方法同Ⅱ组).观察支气管Clara细胞百分率、血清和肺泡灌洗液(BALF)中CCSP含量、BALF中白细胞计数及中性粒细胞比值、血清肿瘤坏死因子α(TNF-α)、白细胞介素(IL)-6、IL-8水平、肺组织湿/干比值和肺组织病理学检查.结果 Clara细胞百分率、CCSP含量Ⅰ组高于Ⅱ组(P<0.05),Ⅱ组高于Ⅲ组(P(0.01);BALF中白细胞计数、中性粒细胞比值和血清中TNF-α、IL-6、IL-8水平、肺湿/干比值Ⅰ组低于Ⅱ组(P<0.05),Ⅱ组低于Ⅲ组(P<0.01);病理学检查示肺损伤程度Ⅰ组轻于Ⅱ组,Ⅱ组轻于Ⅲ组.结论 Clara细胞分泌蛋白可减轻单肺通气所致肺损伤.     

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.     

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.     

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.     

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.