不同负荷剂量右美托咪定对心脏传导系统的影响

目的探讨单次泵注不同负荷剂量右美托咪定对心脏传导系统的影响。方法择期行骨科手术男性患者80例,年龄20~65岁,ASAⅠ或Ⅱ级,随机分为四组,每组20例。D1、D2、D3组分别采用微量泵输注右美托咪定0.3、0.5和0.8μg/kg,C组以同样方式输注等容量生理盐水,输注时间为10min。记录泵注前(T_1)、泵注后5min(T_2)、10min(T_3)、泵注结束后10min(T_4)时患者MAP、HR、SpO_2和12导联ECG,计算P波时限、P-R间期、QRS时限和QTc值。结果 T_2~T_4时D2、D3组MAP明显低于,HR明显慢于T_1时和C组(P0.05)。T_2~T_4时D2、D3组QTc值明显短于T_1时和C组(P0.05)。四组P波时限、P-R间期和QRS时限组间组内差异无统计学意义。结论右美托咪定不影响心脏传导系统,0.5及0.8μg/kg负荷剂量右美托咪定可有效缩短QT间期,但可能对基础心率偏慢患者宜选用不超过0.5μg/kg负荷剂量右美托咪定,避免严重心动过缓。     

右美托咪定对胃癌手术老年患者红细胞糖代谢限速酶和血糖及丙二醛浓度的影响

目的观察右美托咪定对胃癌手术老年患者红细胞糖代谢限速酶活性和血糖及丙二醛(MDA)浓度的影响。方法选择胃癌手术老年患者60例,男38例,女22例,年龄60~80岁,ASAⅠ或Ⅱ级,随机分为两组,每组30例。右美托咪定组(D组)术前10 min静脉泵注右美托咪定0.5μg/kg,术中右美托咪定静脉维持0.3μg·kg~(-1)·h-1,对照组(C组)术前、术中静脉泵注等量的生理盐水。分别于麻醉前(T_0)、手术60min(T_1)、术后60 min(T_2)、术后1d晨(T_3)和术后2d晨(T_4)抽取肘静脉血,测定红细胞磷酸果糖激酶(PFK)、葡萄糖-6-磷酸脱氢酶(G-6PD)和醛糖还原酶(AR)的活性及血糖和血浆丙二醛(MDA)的浓度。结果与T_0时比较,T_3时两组PFK活性明显降低(P0.05),G-6PD和AR活性明显升高(P0.05或P0.01),且D组PFK活性明显高于、G-6PD和AR活性明显低于C组(P0.05)。T_1时两组血糖浓度开始升高(P0.01),至T_3时达峰值(P0.01);T_1~T_3时D组血糖浓度均明显低于C组(P0.05)。与T_0时比较,T_3时两组血浆MDA浓度在T_3时明显升高(P0.01),D组MDA浓度明显低于C组(P0.05)。结论右美托咪定可降低胃癌手术老年患者围术期血糖浓度,减轻氧化应激,改善红细胞糖代谢状态。     

右美托咪定对腭咽成形术患者围术期应激反应的影响

目的观察右美托咪定对腭咽成形术(uvulopalatopharyngoplasty,UPPP)患者围术期应激反应的影响。方法选择择期行腭咽成形术的男性患者60例,年龄18~65岁,ASAⅠ或Ⅱ级,随机分为右美托咪定组(D组)和对照组(C组),每组30例。D组气管插管前先予负荷剂量右美托咪定1.0μg/kg 10min,术中及入ICU后持续静脉泵注右美托咪定0.5μg·kg~(-1)·h~(-1);C组持续泵入等容量生理盐水。记录入室(T_0)、气管插管成功即刻(T_1)、手术开始30min(T_2)、入ICU即刻(T_3)、拔除气管导管即刻(T_4)的MAP、HR;检测T_0~T_4时动脉血PaO_2、PaCO_2及去甲肾上腺素(NE)、肾上腺素(E)、皮质醇(Cor)、IL-6、T_NF-α的浓度;记录入ICU后苏醒时间、拔管时间、ICU停留时间及呛咳反应的发生情况。结果 T_1~T_4时D组HR明显慢于C组,MAP明显低于C组(P0.05);T_1~T_4时D组NE、E、Cor、IL-6、T_NF-α浓度明显低于C组(P0.05);D组拔管期呛咳发生率为9例(30%),明显低于C组的21例(70%)(P0.05)。两组苏醒时间、拔管时间及ICU停留时间差异无统计学意义。结论围术期静脉泵注右美托咪定可有效抑制腭咽成形术患者的应激反应,维持循环稳定,且不延长患者苏醒时间、拔管时间及ICU停留时间。     

不同剂量右美托咪定对腹腔镜下胃肠手术老年患者围术期应激反应的影响

目的观察不同剂量右美托咪定对腹腔镜下胃肠手术老年患者围术期应激反应的影响。方法择期行腹腔镜下胃肠手术老年患者80例,性别不限,年龄≥65岁,ASAⅠ或Ⅱ级。随机分为四组,每组20例。所有患者均采用全凭静脉麻醉。D1、D2组和D3组麻醉诱导前10min静脉泵注右美托咪定0.5μg/kg,插管后分别静脉泵注右美托咪定0.2、0.5、0.8μg·kg~(-1)·h~(-1)至术毕前30min;C组麻醉诱导前10min静脉泵注7ml生理盐水,插管后静脉泵注生理盐水10ml/h至术毕前30min。记录术中麻醉药物用量,记录给药前(T_0)、气管插管后即刻(T_1)、气腹后5min(T_2)、气腹后60min(T_3)、拔管后即刻(T_4)和拔管后10min(T_5)的HR、SBP、DBP,分别于T_0、T_1、T_3、T_5时抽取桡动脉血,测定Glu、Cor、E和NE浓度。结果 D1组、D2组和D3组术中瑞芬太尼的用量明显少于C组,且D2组和D3组明显少于D1组(P0.05)。与T_0时比较,T_1~T_5时C组HR明显增快(P0.05)。T_2~T_5时,D2组和D3组的HR明显慢于C组和D1组,SBP明显低于C组(P0.05);T_1时D2组和D3组Cor和NE浓度也明显低于C组(P0.05)。T_3和T_5时,D2组和D3组Glu、Cor、E和NE浓度明显低于C组,D2组和D3组Cor和NE浓度明显低于D1组(P0.05)。结论与0.2和0.8μg·kg~(-1)·h~(-1)右美托咪定静脉泵注维持比较,0.5μg·kg~(-1)·h~(-1)能更有效抑制腹腔镜下胃肠手术老年患者围术期应激反应。     

不同剂量右美托咪定对老年结直肠癌根治术患者围术期免疫功能的影响

目的评价不同剂量右美托咪定对老年结直肠癌根治术患者围术期免疫功能的影响。方法选择2015年1月至2018年3月拟于本院行结直肠癌根治术的患者共计90例。采用随机软件将纳入患者随机分为3组:低剂量右美托咪定组(D_(0.25)组)、标准剂量右美托咪定组(D_(0.5)组)和空白对照组(C组),每组患者各30例。D_(0.25)组和D_(0.5)组患者均于麻醉诱导前15分钟内静脉泵注右美托咪定0.5ug/kg。D_(0.5)组患者继续维持右美托咪定剂量为0.5μg/kg/h;D_(0.25)组患者则调整泵注剂量为0.25μg/kg/h。C组患者泵注等量0.9%氯化钠注射液作为空白对照。记录三组患者术中低血压、心动过缓人数及麻黄碱、阿托品等血管活性药物使用人数。记录患者拔管时间、术后恶心呕吐(PONV)、寒战、苏醒期躁动、苏醒延迟发生人数。于麻醉诱导前30分钟(T_0)、右美托咪定负荷剂量注射完毕后(T_1)、手术开始后1小时(T_2)、手术结束即刻(T_3)抽取外周静脉血,采用流式细胞术检测上述标本CD3~+、CD4~+、CD8~+、CD4~+/CD8~+比值及NK细胞水平。结果 D_(0.5)组患者术中低血压、心动过缓人数及阿托品使用人数显著高于D_(0.25)组和C组患者,差异有统计学意义(P0.05)。D_(0.5)组患者拔管时间显著长于D_(0.25)组和C组患者,差异有统计学意义(P0.05)。D_(0.25)组和D_(0.5)组患者T_2、T_3时点CD3~+、CD4~+、CD4~+/CD8~+比值及NK细胞水平均显著高于C组患者,差异有统计学意义(P0.05)。D_(0.25)组和D_(0.5)组患者间各时点CD3~+、CD4~+、CD4~+/CD8~+比值及NK细胞水平差异均无统计学意义(P0.05)。结论术中持续泵注右美托咪定0.25ug/kg/h能够改善结直肠癌根治术老年患者术中免疫功能,并且不影响患者术中血流动力学稳定和术后苏醒,值得在临床中推广使用。     

右美托咪定可减轻肺叶切除术中单肺通气所致肺损伤

目的探讨右美托咪定对肺叶切除术中单肺通气所致肺损伤的影响。方法选择2014年5月至2017年2月拟行肺叶切除术的肺癌患者64例,男38例,女26例,年龄42~75岁,ASAⅡ或Ⅲ级。根据不同治疗方式将患者分成两组,每组32例。麻醉诱导前20min,观察组泵注右美托咪定0.5μg·kg~(-1)·h~(-1),10min后改为0.2~0.5μg·kg~(-1)·h~(-1),对照组予以等容量生理盐水。检测麻醉诱导前10min(T_0)、单肺通气即刻(T_1)、单肺通气60min(T2)、单肺通气90min(T_3)、术后24h(T_4)的全血中性粒细胞(PMN)计数,血清髓过氧化物酶(MPO)、黄嘌呤氧化酶(XOD)活性,肺内分流率(Qs/Qt),以及T_0~T_3时血管内皮生长因子(VEGF)和一氧化氮(NO)浓度。结果与T_0时比较,T_2~T_4时两组PMN计数明显增多,MPO和XOD活性明显升高(P0.05),但观察组明显低于对照组(P0.05)。与T_0时比较,T_2、T_3时两组血清VEGF浓度明显升高,但T_3时观察组明显低于对照组(P0.05)。T_2、T_3时观察组血清NO浓度明显高于对照组(P0.05)。结论右美托咪定能减少患者肺部炎症反应,减轻单肺通气所致缺血-再灌注损伤,且降低了患者机体氧化应激程度,从而对肺起到保护作用。     

右美托咪定通过腺苷A1受体调节大鼠压力反射敏感性

目的观察腺苷A1受体在右美托咪定调节压力反射敏感性(baroreflex sensitivity,BRS)中的作用。方法健康成年雄性SD大鼠32只,体重240~280g,按随机数字表随机分为四组:对照组(C组)、选择性腺苷A1受体阻断剂组(P组)、右美托咪定组(D组)、选择性腺苷A1受体阻断剂+右美托咪定组(PD组),每组8只。C组泵注生理盐水40 ml·kg~(-1)·h~(-1)负荷量15 min,维持泵注10 ml·kg~(-1)·h~(-1);P组腹腔注射选择性腺苷A1受体阻断剂8-环戊基-1,3-二丙基黄嘌呤(DPCPX)1mg/kg,泵注同C组方案的生理盐水;D组右美托咪定负荷量100μg/kg,维持量100μg·kg~(-1)·h~(-1)持续泵注;PD组腹腔注射DPCPX 1mg/kg并泵注右美托咪定,泵注剂量同D组。采用苯肾上腺素升压法于泵注前(T_0)、泵注后60min(T_1)和泵注后120min(T_2)测定BRS。结果与T_0时比较,T_1和T_2时D组和PD组BRS明显升高(P0.05)。与C组和P组比较,T_1和T_2时D组和PD组BRS均明显升高(P0.05)。与D组比较,T_1和T_2时PD组BRS明显降低(P0.05)。结论右美托咪定可能通过腺苷A1受体增加大鼠BRS。     

右美托咪定复合乌司他丁对老年胃肠肿瘤切除术患者术后谵妄的影响

目的观察右美托咪定复合乌司他丁对老年患者行腹腔镜下胃肠肿瘤切除手术术后谵妄(POD)的影响。方法选择2015年9月至2016年1月择期行腹腔镜下胃肠肿瘤切除术患者180例,男97例,女83例,年龄65~80岁,ASAⅡ或Ⅲ级,采用随机数字表法随机分为四组:右美托咪定组(D组)、乌司他丁组(U组)、右美托咪定+乌司他丁组(DU组)和生理盐水组(C组),每组45例。麻醉诱导前,D组给予右美托咪定负荷剂量0.5μg/kg,输注15min后以0.3μg·kg~(-1)·h~(-1)持续泵注,手术结束前40min停止输注;U组静注乌司他丁10 000U/kg,15~20min内完成;DU组先静注乌司他丁10 000U/kg,15~20min内完成,再给予右美托咪定负荷剂量0.5μg/kg,输注15min后以0.3μg·kg~(-1)·h~(-1)持续泵注,手术结束前40min停止输注;C组给予等容量生理盐水。记录手术时间、术中出血量、尿量和补液量;于术前1d(T0)、手术开始(切皮)后1h(T_1)、术后第1天(T_2)、术后第2天(T_3)、术后第3天(T_4)采血检测多巴胺(DA)、肾上腺素(AD)、去甲肾上腺素(NE)浓度;T_0和T_2~T_4时由精神科医师采用谵妄评定量表中文修订版(CAM-CR)对患者谵妄情况进行评估,记录谵妄的发生例数。结果与T_0时比较,T_1~T_4时U组和C组DA、AD和NE浓度明显升高,T_1时D组和DU组的DA浓度明显升高,T_1、T_2时D组和DU组的AD浓度明显升高(P0.05);T_2~T_4时D组和DU组DA和AD浓度明显低于C组和D组,T_1~T_4时D组和DU组的NE浓度明显低于C组和D组(P0.05)。D组、U组和DU组POD发生率明显低于C组(P0.05);D组、U组和DU组POD发生率差异无统计学意义。结论单独使用右美托咪定或乌司他丁可以降低老年患者腹腔镜下胃肠肿瘤切除手术POD发生率,两种药物复合使用并不能进一步降低POD发生率。     

右美托咪定对异体肾移植患者围术期肾功能的影响

目的研究右美托咪定对同种异体肾移植患者围术期肾功能的影响。方法选择行同种异体肾移植患者60例,男36例,女24例,年龄25~45岁,ASAⅡ或Ⅲ级,随机分为两组:右美托咪定组和对照组,每组30例。右美托咪定组麻醉诱导前给予右美托咪定1μg/kg泵注10min,随后以0.6μg·kg~(-1)·h~(-1)维持泵注至手术结束前30min;对照组以等容量生理盐水维持至手术结束前30min。记录两组患者在麻醉诱导前(T_1)、吻合血管开放前(T_2)、吻合血管开放后即刻(T_3)、吻合血管开放后30min(T_4)和手术结束后(T_5)的HR和SBP,于T_2、T_4、术后24h(T6)及术后48h(T7)采取静脉血检测血尿素氮(BUN)、血肌酐(Cr)、IL~(-1)8和半胱氨酸蛋白酶抑制剂C(Cys C)的浓度;记录术中液体输注量和尿量。结果 T_3时右美托咪定组HR明显慢于对照组;T_2、T_3时右美托咪定组SBP明显高于对照组(P0.05)。与T_2时比较,T6、T7时两组Cys C、BUN、Cr浓度明显降低,且T7时右美托咪定组Cys C浓度明显低于对照组(P0.05)。与T_2时比较,T6、T7时两组IL~(-1)8浓度明显降低,且右美托咪定组降低幅度明显大于对照组(P0.05)。右美托咪定组围术期尿量明显多于对照组(P0.05)。两组术中液体输注量差异无统计学意义。结论围术期应用右美托咪定可有效保护肾移植患者的肾功能。     

右美托咪定对腹腔镜全子宫切除术患者早期 认知功能及TNF-α的影响

目的:探讨右美托咪定对腹腔镜全子宫切除术患者早期认知功能及肿瘤坏死因子-α(TNF-α)的影响。方法:选取择期全身麻醉下行腹腔镜全子宫切除术的60例患者(45～60岁,ASAⅠ～Ⅱ级),随机分为对照组与右美托咪定组(观察组),每组30例。观察组于麻醉诱导前15 min静脉持续泵注右美托咪定1.0μg/kg,然后以0.5μg/kg·h~(-1)持续泵注至术毕前30 min;对照组患者泵注等量生理盐水。分别于术前1 d(T_0)及术后第1天(T_1)、第2天(T_2)、第3天(T_3)采集患者外周静脉血,采用ELISA法测定血清中TNF-α水平,同时采用简易精神状态评价量表(MMSE)评价认知功能。结果:与T_0相比,T_1～T_3时,两组患者MMSE评分降低(P0.05),血清TNF-α浓度升高(P0.05)。与对照组相比,观察组患者T_1～T_3时血清TNF-α水平降低(P0.05)。T_3时,两组患者术后认知功能障碍发生率分别为36.67%与13.33%,两组差异有统计学意义(P0.05)。结论:右美托咪定能降低腹腔镜全子宫切除术患者术后早期认知功能障碍发生率,下调血清TNF-α水平表达。     

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.