近日节律对靶控输注依托咪酯镇静效应的影响

目的通过上午、下午靶控输注(TCI)依托咪酯麻醉诱导时依托咪酯血浆靶浓度测定,探讨近日节律对TCI依托咪酯镇静效应的影响。方法选择术前未用药患者60例,ASAⅠ或Ⅱ级,随机分为上午组(8:00~10:00,A组,30例)和下午组(14:00~16:00,P组,30例)TCI依托咪酯进行全麻诱导。以血浆靶浓度150 ng/ml为起点,达到预期的血浆靶浓度5 min后,每次增加50 ng/ml,直到患者意识消失(睫毛反射消失及OAA/S评分≤3分,且BIS≤50)。记录BIS为50和意识消失时的依托咪酯血浆靶浓度。结果 BIS达50和意识消失时,两组患者HR、MAP、SpO2、BIS差异均无统计学意义。与P组比较,BIS达50和意识消失时,A组依托咪酯血浆靶浓度明显升高(P0.05)。结论近日节律对依托咪酯的镇静作用有影响,下午组TCI依托咪酯患者BIS达50和意识消失时所需血浆靶控浓度较低。     

靶控输注依托咪酯复合瑞芬太尼用于支气管超声引导内镜针吸活检术的效果

目的 评价靶控输注依托咪酯复合瑞芬太尼用于支气管超声引导内镜针吸活检术的效果.方法 择期拟行支气管超声引导内镜针吸活检术患者69例,ASA分级Ⅰ或Ⅱ级,性别不限,年龄35～71岁,体重41～ 83 kg,采用随机数字表法,将患者随机分为3组(n=23),Ⅰ组麻醉诱导采用靶控输注异丙酚,血浆靶浓度3～4μg/ml,静脉注射芬太尼4μg/ml;Ⅱ组麻醉诱导采用靶控输注异丙酚,血浆靶浓度3～4μg/ml,靶控输注瑞芬太尼,血浆靶浓度5 ng/ml;Ⅲ组麻醉诱导采用靶控输注依托咪酯,血浆靶浓度0.3 ～ 0.4 μg/ml,靶控输注瑞芬太尼,血浆靶浓度5ng/ml.待患者意识消失后置入喉罩,行机械通气,维持PETCO2 30 ～40 mm Hg.术中维持BIS值40～60.记录术中血管活性药物(佩尔地平、麻黄碱、阿托品和艾司洛尔)使用情况、呛咳发生情况、苏醒时间、术后24h恶心呕吐发生情况.于麻醉诱导前30 min、术毕即刻和术后24h,采集股静脉血样,采用放射免疫法测定血浆皮质醇浓度.结果 与Ⅰ组比较,Ⅱ组和Ⅲ组呛咳和恶心呕吐的发生率降低,苏醒时间缩短,Ⅲ组血管活性药使用率降低(P＜0.05);与Ⅱ组比较,Ⅲ组血管活性药物使用率降低(P＜0.05).与Ⅰ组和Ⅱ组比较,Ⅲ组术毕时血浆皮质醇浓度降低(P＜0.05);Ⅰ组和Ⅱ组间各时点血浆皮质醇浓度差异无统计学意义(P＞0.05).结论 靶控输注依托咪酯(血浆靶浓度0.3～0.4 μg/ml)复合瑞芬太尼(血浆靶浓度5ng/ml)用于支气管超声引导内镜针吸活检术的麻醉效果好,不良反应少.     

不同血浆靶浓度瑞芬太尼对患者异丙酚镇静效应的影响

目的 探讨不同血浆靶浓度瑞芬太尼对患者异丙酚镇静效应的影响.方法 择期拟行腹腔镜胆囊切除术患者80例,性别不限,ASA分级Ⅰ或Ⅱ级,年龄18～60岁,随机分为4组,每组20例.麻醉诱导:Ⅱ～Ⅳ组靶控输注瑞芬太尼,血浆靶浓度分别设为2、4、8 ng/ml,Ⅰ～Ⅳ组均靶控输注异丙酚,初始血浆靶浓度为2μg/ml,随后每间隔1min增加0.5μg/ml,直至BIS值下降至50.患者意识消失时记录BIS值和异丙酚血浆靶浓度,BIS值降至50时记录异丙酚血浆靶浓度及异丙酚总用量.结果 与Ⅰ组比较,Ⅲ组和Ⅳ组患者意识消失时BIS值升高,异丙酚血浆靶浓度降低,BIS值降至50时异丙酚总用量和异丙酚血浆靶浓度降低(P＜0.05).结论 复合异丙酚麻醉时,瑞芬太尼适宜血浆靶浓度为4 ng/ml.     

不同效应室靶浓度瑞芬太尼对患者意识消失和伤害性刺激诱发体动反应消失时依托咪酯半数有效浓度的影响

目的 探讨不同效应室靶浓度瑞芬太尼对患者意识消失和伤害性刺激诱发体动反应消失时依托咪酯半数有效浓度(EC50)的影响.方法 择期拟在全身麻醉下行妇科手术患者80例,ASA 分级Ⅰ或Ⅱ级,年龄18～64岁,采用随机数字表法,将患者随机分为4组(n=20):R0组不使用瑞芬太尼;R1～3组瑞芬太尼效应室靶浓度分别为1、2、3ng/ml.麻醉诱导开始时先靶控输注瑞芬太尼,达设定效应室靶浓度后,再以血浆靶浓度0.6μg/ml为起点开始靶控输注依托咪酯,此后每分钟增加依托咪酯的血浆靶浓度0.1 μg/ml直至患者意识消失及对伤害性刺激诱发体动反应消失.记录患者意识消失及对伤害性刺激诱发体动反应消失时依托咪酯的效应室靶浓度,采用Probit法计算EC50.结果 随瑞芬太尼效应室靶浓度升高,患者意识消失时和伤害性刺激诱发体动反应消失时依托咪酯的EC50逐渐降低(P<0.05).结论 靶控输注1、2.3 ng/ml的瑞芬太尼可呈浓度依赖性地强化依托咪酯的镇静镇痛作用.

Abstract：

Objective To investigate the effect of different target effect-site concentrations (Ces) ofremifentanil on the median effective concentration (EC50 ) of etomidate required for loss of consciousness and disappearance of nociceptive stimuli-induced body movement. Methods Eighty ASA Ⅰ orⅡ patients aged 18-64 yr scheduled for elective gynecological surgery under general anesthesia were randomly divided into 4 groups ( n = 20 each): group R0 received no remifentanil and R1-3 groups received remifentanil at 3 predetermined target Ces of 1,2 and 3 ng/ml respectively. At the beginning of anesthesia induction, remifentanil was given by target-controlled infusion (TCI) until the predetermined Ces were achieved, TCI of etomidate was then started at a target plasma concentration of 0.6 μg/ml and then the target plasma concentration of etomidate increased by 0.1 μg/ml every 1 min until the patients lost consciousness and the body movement induced by the nociceptive stimuli disappeared. The Ce of etomidate required for loss of consciousness and disappearance of nociceptive stimuli-induced body move-ment was recorded and the EC50 was calculated by Probit method. Results With the increase in the target Ces of remifentanil, the EC50 of etomidate required for loss of consciousness and disappearance of nociceptive stimuli-induced body movement decreased gradually (P < 0.05) .Conclusion Remifentanil given by TCI can enhance the sedative and analgesic effect of etomidate concentration-dependently.     

右美托咪啶对靶控输注异丙酚意识消失时BIS值的影响

目的 评价右美托咪啶对靶控输注异丙酚意识消失时脑电双频谱指数(BIS)值的影响.方法 择期行普外科手术患者120例,性别不限,年龄25～50岁,体重41～68 kg,ASA分级Ⅰ或Ⅱ级,采用随机数字表法,将患者随机分为3组(n=40):异丙酚组(P组)、右美托咪啶0.5μg/kg+异丙酚(D1P组)和右美托咪啶1.0μg/kg+异丙酚(D2P组).每组再分为5个亚组(n=8):异丙酚效应室靶控浓度0、1、2、3和4 mg/L组(P0～4组).P0～4组靶控输注异丙酚,效应室靶浓度分别为0、1、2、3和4 mg/L;D1 P0～4组静脉输注右美托咪啶0.5 μg/kg,输注速率0.05μg·kg-1·min-1,输注结束后5min时靶控输注异丙酚,效应室靶浓度分别为0、1、2、3和4 mg/L;D2 P0～4组静脉输注右美托咪啶1.0μg/kg,输注速率0.1 μg· kg-1 ·min-1,输注结束后5min时靶控输注异丙酚,效应室靶浓度分别为0、1、2、3和4mg/L.异丙酚靶控输注3 min时记录OAA/S评分和BIS值,OAA/S评分≤2分判定为意识消失.采用Probit法计算半数患者意识消失时异丙酚的效应室靶浓度(EC50)和半数患者意识消失时的BIS值(BIS50)及其95％可信区间,采用Smith法计算BIS值对意识消失的预测概率.结果 与P组比较,D1P组和D2P组EC50降低,BIS50升高(P＜0.05或0.01),预测概率差异无统计学意义(P＞0.05);D1P组和D2P组EC50、BIS50和预测概率比较差异无统计学意义(P＞0.05).结论 右美托咪啶复合靶控输注异丙酚时BIS 值可准确预测患者的意识水平,而意识消失时的BIS值增加.     

丙泊酚靶控输注诱导致肾移植患者意识消失的量效关系

目的探讨终末期肾功能衰竭(end-stage renal disease,ESRD)拟行亲体肾移植患者的丙泊酚靶控输注(target controlled infusion,TCI)诱导剂量,并与正常人群对照,探讨丙泊酚在ESRD患者麻醉诱导致意识消失(loss of consciousness,LOC)的量效关系。方法 ESRD患者拟行亲属活体肾移植手术受体20例(E组);选取ASAⅠ或Ⅱ级,相近年龄、体重,性别构成相同,择期全麻手术患者20例为对照组(C组)。靶控诱导时设定起始丙泊酚血浆靶浓度为1.5mg/L,递增浓度为0.5mg/L,每一靶浓度输注1min;记录LOC时间、LOC时的BIS值,诱导剂量所致的BIS最低值、LOC时丙泊酚的血浆、效应室浓度、丙泊酚剂量及麻醉前(基础值)以及LOC时HR、MAP、SpO2和BIS。结果 E组LOC时间为(273±78)s,明显长于C组的(197±42)s(P0.05);E、C组LOC时丙泊酚血浆浓度分别为(5.8±1.0)、(4.8±1.0)mg/L,效应室浓度分别为(5.1±1.0)、(4.2±0.8)mg/L,E组LOC时丙泊酚血浆浓度和效应室浓度明显高于C组(P0.05);但两组LOC时BIS值及诱导剂量所致的BIS最低值差异无统计学意义;麻醉前E组MAP明显高于C组(P0.01);两组LOC时MAP明显低于,HR明显慢于麻醉前(P0.05或P0.01)。结论与肾功能正常患者比较,ESRD患者所需丙泊酚剂量更大,LOC时间延长,提示ESRD患者麻醉诱导时,需要加大丙泊酚的诱导剂量,以达到足够麻醉深度。     

靶控输注右美托咪定对丙泊酚致意识消失效应室半数有效浓度的影响

目的观察静脉靶控输注(target-controlled infusion,TCI)右美托咪定对丙泊酚致患者意识消失效应室半数有效浓度(Ce_(50))的影响。方法选择择期行喉罩全麻下手术患者64例,男28例,女36例,年龄20~60岁,ASAⅠ或Ⅱ级,随机分为四组:空白组(P组)、低浓度右美托咪定组(D1组)、中浓度右美托咪定组(D2组)和高浓度右美托咪定组(D3组),每组16例。麻醉诱导时分别以0、0.4、0.6和0.8ng/ml的血浆靶浓度靶控输注右美托咪定15min,然后以初始效应室靶浓度(Ce)1.0μg/ml靶控输注丙泊酚。每次待丙泊酚的效应室浓度与靶浓度平衡时以0.2μg/ml逐步升高丙泊酚的靶浓度,直至患者意识消失。观察和计算患者意识消失时丙泊酚的Ce50及其95%CI,观察麻醉诱导过程中不良反应情况。结果 P、D1、D2和D3组丙泊酚致意识消失Ce50及其95%CI分别为2.30(2.24~2.36)、1.92(1.87~1.96)、1.60(1.55~1.65)和1.41(1.35~1.45)μg/ml。丙泊酚致意识消失的效应室浓度与右美托咪定的血浆靶浓度呈负相关关系(r=-0.84,P0.01)。与P、D1和D2组比较,D3组心动过缓的发生率明显增加(P0.05)。结论随着右美托咪定血浆靶浓度的升高,丙泊酚致意识消失Ce_(50)逐渐降低。靶控输注右美托咪定0.4或0.6ng/ml能明显降低丙泊酚致意识消失Ce50,心动过缓发生率较低,适合辅助丙泊酚进行麻醉诱导。     

依托咪酯乳剂诱导时雷米芬太尼抑制气管插管反应的效应室靶浓度

目的 测定依托咪酯乳剂诱导时雷米芬太尼抑制气管插管反应的效应室靶浓度(EC50和EC95).方法 选择23例ASAⅠ或Ⅱ级全麻择期手术患者靶控输注(TCI)雷米芬太尼,血浆浓度与效应室浓度达到平衡后静脉注射依托咪酯乳剂0.3 mg/kg,患者意识消失后静脉注射琥珀胆碱行气管插管.气管插管后2 min内最高的SBP和/或HR高出基础值15%为气管插管反应阳性.雷米芬太尼靶浓度按改良序贯法增加或减少0.5 ng/ml.用概率单位回归分析法计算出雷米芬太尼抑制气管插管反应的EC50、EC95及相应的95%可信区间(CI).结果 雷米芬太尼抑制气管插管反应的EC50为3.06 ng/ml,95%CI为2.56～3.47 ng/ml;相应的EC95为3.85 ng/ml,95%CI为3.45～6.64ng/ml.结论 复合依托咪酯0.3 mg/kg诱导时雷米芬太尼抑制气管插管反应的EC50和EC95分别为3.06 ng/ml和3.85 ng/ml.     

七氟醚和依托咪酯镇静催眠效应的相互作用

目的 评价七氟醚和依托咪酯镇静催眠效应的相互作用.方法 择期全麻手术患者24例,ASA Ⅰ或Ⅱ级,年龄18～59岁,体重指数17～27 kg/m2.试验Ⅰ 12例患者靶控输注依托咪酯,效应室靶浓度依次为0.05、0.1、0.2、0.3、0.4、0.5 μg/ml.效应室浓度依次达到预设浓度2 min时,记录反应熵(RE)、状态熵(SE)和警觉/镇静(OAA/S)评分,然后停止输注依托咪酯.随机分为3组(n=4),A1组、B1组、C1组吸入七氟醚,呼气末浓度分别为0.5%、1%、2%.七氟醚呼气末浓度达预定浓度的95%或以上时,靶控输注依托咪酯,效应室靶浓度依次为0.2、0.3、0.4、0.5 μg/ml.效应室浓度依次达到预设浓度2 min时,记录RE、SE和OAA/S评分.试验Ⅱ 12例患者吸入七氟醚,呼气末浓度依次为0.5%、1%、2%、3%、4%、5%.依次达到预定呼气末浓度时,记录RE、SE和OAA/S评分,然后停止吸人七氟醚,吸氧洗脱七氟醚.随机分为3组(n=4),A2组、B2组、C2组靶控输注依托咪酯,效应室靶浓度分别为0.05、0.1、0.2 μg/ml.效应室浓度达到预设浓度2 min时,吸入七氟醚,呼气末浓度依次为0.5%、1%、2%、3%、4%、5%.依次达到预定呼气末浓度时,记录RE、SE和OAA/S评分.采用反应曲面法评价RE、SE和OAA/S评分,判断七氟醚和依托咪酯镇静催眠效应的相互作用.结果 RE和SE的相互作用指数的拟合值及其95%可信区间分别为0.32(-0.07～0.71)、0.25(-0.12～0.63)(P>0.05).OAA/S评分的相互作用指数的拟合值及其95%可信区间为2.25(0.58～3.93)(P<0.05).结论 以脑电熵指数反映镇静催眠效应时七氟醚和依托咪酯为相加作用;以OAA/S评分反映镇静催眠效应时七氟醚和依托咪酯为协同作用.     

不同年龄患者清醒镇静时靶控输注咪达唑仑的效应室浓度和BIS水平

目的 探讨不同年龄患者靶控输注(TCI)咪达唑仑清醒镇静时效应室浓度(Ce)和脑电双频谱指数(BIS)水平.方法 择期椎管内麻醉下行下肢或下腹部手术患者60例,ASA Ⅰ或Ⅱ级,按年龄分为2组(n=30):青年组(Ⅰ组),年龄20～40岁;老年组(Ⅱ组),年龄≥65岁.麻醉平面均控制在T8以下.TCI咪达唑仑,以Ce为目标靶浓度,初始靶浓度为40 ng/ml,然后以10 ng/ml的浓度梯度递增,每一靶浓度维持15 min.术中每5分钟进行遗忘测试及警觉/镇静(OAA/S)评分1次(患者对正常语调呼名反应快为5分;对轻推或摇动无反应为1分),OAA/S评分达1分时停药.于咪达唑仑给药前即刻和达不同OAA/S评分时记录MAP、HR和SpO2;于OAA/S评分前即刻记录Ce和BIS.术后24h让患者挑出术中不同OAA/S评分时所看到的图片,记录遗忘发生情况.结果 2组OAA/S评分与Ce呈负相关,与BIS呈正相关,OAA/S评分与Ce的相关性低于BIS(P＜0.05);当OAA/S评分≤4时,Ⅱ组Ce低于Ⅰ组,而BIS高于Ⅰ组(P＜0.05);2组Ce、BIS的预测概率比较差异无统计学意义(P＞0.05).结论 BIS和Ce在评价不同年龄患者咪达唑仑的镇静深度及预测意识消失方面均有重要价值.当遗忘率达100%,青年组Ce为(74.3±21.5)ng/ml,BIS为61.6±7.9;老年组Ce为(58.3±12.5)ng/ml,BIS为82.3±4.2.     

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.     

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.     

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.