全麻复合硬膜外阻滞对单肺通气期间肺内分流的影响

目的：探讨全麻复合高位硬膜外阻滞对单肺通气期间肺内分流（Qs/Qt )的影响。方法：择期开胸手术病人30例随机分为两组：全麻复合硬膜外组（A组）和全麻组（B组）。两组病人分别于麻醉前、双肺通气20分钟、单肺通气15、30分钟时采动脉血及混合静脉血行血气分析，并计算出Qs/Qt等。结果：单肺通气时，两组病人Qs/Qt较双肺通气时显著增加（P＜0．01），PaO2显著降低（P＜0．05）。单肺通气15、30分钟时，A组病人Qs/Qt显著大于B组（P＜0．01）；PaO2显著低于B组（P＜0．05）。麻醉期间A组病人心率亦显著慢于B组（P＜0．05）。结论：单肺通气期间，全麻复合硬膜0．05）。麻醉期间A组病人心率亦显著慢于B组（P＜0．05）。结论：单肺通气时间，全麻复合硬膜外阻滞可引起Qs/Qt增加，PaO2降低，可能与硬膜外阻滞削弱低氧性肺血管收缩机制（HPV）有关。     

全麻复合硬膜外阻滞对单肺通气期间动脉血气的影响

目的观察全麻复合胸段硬膜外阻滞对单肺通气期间动脉血气及肺内分流的影响。方法选择ASAⅠ-Ⅱ级择期开胸手术病人80例,将病人随机分为两组,全麻复合硬膜外阻滞组（A组）和全麻组（B组）,每组40例。两组患者在开胸前双肺通气20min（T1）时及开胸后单肺通气（OLV）15min、60min、120min（T2-4）时,分别采动脉血及混合静脉血,观察患者动静脉血气情况并计算肺内分流率（Qs／Qt）值。结果两组术中PaCO2、pH均在正常范围内,各时点PaCO2、pH、Paw组间比较无统计学意义。与T1相比,A组、B组T2～4时Paw及Qs／Qt均增加,PaO2均降低（P〈0.05）。与B组相比,A组T2-4时的Qs／Qt增加更明显,PaO2降低更明显（P〈0．05）。结论胸科手术单肺通气期间,全麻复合硬膜外阻滞有增加Qs／Qt,使PaO2下降的风险。因此全麻复合硬膜外阻滞应用于开胸手术病人时,应严密加强血气监测。     

选择性肺叶通气对肺功能不全患者开胸术中肺内分流及炎性反应的影响

目的 评价选择性肺叶通气对肺功能不全患者开胸术中肺内分流和炎性反应的影响.方法 择期行食管癌根治术患者34例,年龄64～79岁,体重50～85 kg,ASA分级Ⅱ或Ⅲ级,合并中重度肺功能不全,采用随机数字表法,将其随机分为2组(n=17):单肺通气组(A组)和选择性肺叶通气组(B组).A组患者使用支气管堵塞器堵塞主支气管实施单肺通气;B组患者使用支气管堵塞器堵塞肺叶支气管,实施选择性肺叶通气.于麻醉诱导前(To)、侧卧位双肺通气30 min (T1)、单肺通气或选择性肺叶通气60 min(T2)和术毕(T3)时,记录气道平台压(Pplat)和气道峰压(Ppeak);采集桡动脉、中心静脉血样,进行血气分析,计算肺内分流率(Qs/Qt),采用ELISA法测定血浆TNF-α、IL-6和IL-8的浓度.结果 A组3例患者(18％)发生低氧血症,B组均未发生低氧血症,A组低氧血症发生率高于B组(P＜0.05).与A组比较,B组T1 -3时Pplat、Ppeak降低,T2时Qs/Qt降低,T2.3时TNF-α、IL-6和IL-8浓度降低(P＜0.05).结论 中重度肺功能不全患者开胸术中,实施选择性肺叶通气可降低肺内分流,减轻炎性反应,有助于减轻机械通气性肺损伤.     

PEEP和CPAP在电视辅助胸腔镜手术行单肺通气时对氧合作用及分流的影响

目的 评价呼气末正压通气(PEEP)和连续气道正压通气(CPAP)在电视辅助胸腔镜手术(VATS)行单肺通气麻醉时对患者血氧合作用的影响。方法 选择30例在VATS下行肺叶切除的单纯肺癌患者,随机分为A、B两组。A组于手术开始后15min(A1)、单肺通气后15min(Az)、患侧肺0cmH2OPEEP健侧肺5cmH2OPEEP后15min(A3)、患侧肺5cmH2OCPAP健侧肺0cmH2OPEEP后15min(A4)、患侧肺5cmH2OCPAP健侧肺5cmH2OPEEP后15min(A5)分别监测平均肺动脉压(PAP)、平均动脉压(MAP)、心率(HR)、动脉血氧分压(PaO2)、混合静脉血氧分压(RVO2)、动脉血氧饱和度(SaO2)、混和静脉血氧饱和度(SVO2)并计算分流(Qs／Qt)值。B组用10cmH2OPEEP和10cmH2OCPAP重复上述过程。结果 与A2相比,A3、A4和A5PaO2显著增加,Qs／Qt值显著降低(P＜0．05),但A3、A4、A5间相比较则无显著性差异(P＞0．05)。B组各时点的各项指标变化与A组类同。结论 在VATS行单肺通气麻醉时,健肺使用PEEP、患肺使用CPAP或联合使用PEEP和CPAP能提高患者手术中的氧合作用,降低Qs／Qt值;与5cmH2O PEEP和CPAP比较,10cmH2O PEEP和CPAP不能进一步改善PaO2和Qs／Qt。     

两种麻醉方法下食道癌根治术患者单肺通气期间肺内分流的比较

目的 比较食管癌根治术患者异丙酚-瑞芬太尼靶控静脉麻醉与异氟醚麻醉下单肺通气（OLV）期间肺内分流的变化。方法 择期行中、下段食管癌左侧开胸切除术患者24例，年龄42，69岁，ASAⅠ或Ⅱ级。随机均分为2组：异丙酚．瑞芬太尼组（PR组）和异氟醚组（ISO组）。PR组靶控输注异丙酚和瑞芬太尼，血浆靶浓度分别为3．2μg／ml和4．5ng／ml；ISO组吸入异氟醚（呼气末浓度为1．5％～2．5％），间断静脉注射芬太尼2μg／kg。持续监测ECG、平均动脉压（MAP）、SpO2、听觉诱发电位指数（AAI）、心脏指数（CI）、气道压（Paw）。麻醉诱导后，插入右双腔支气管导管，分别于平卧位漂浮导管置人后10min（T0）、右侧卧位双肺通气10min（T1）、单肺通气15、30、60、90min（T2～T5）进行动脉血及混合静脉血血气分析，计算肺内分流率（Q0／Q1）。结果 两组术中AAI均低于30，PaCO2、pH在正常范围内，组间各时点AAI、PaCO2、pH和Paw比较差异无统计学意义。与T0相比，两组T2-5时Paw升高，T1-5时Qa／Qt增加，于T2达到高峰；PaO2降低，于T2降至最低（P〈0．05），而CI差异无统计学意义（P〉O．05）。与ISO组比较，T2-5时PR组Qa／Qt降低（P〈0．05），PaO2差异无统计学意义。结论 与异氟醚麻醉比较，异丙酚-瑞芬太尼麻醉在OLV期间可减少食管癌根治术患者肺内分流，但对PaO2的影响不明显。     

不同压力的持续气道正压对化疗后病人单肺通气氧合与分流的影响

目的　探讨应用一种新的持续气道正压 (CPAP)系统在肺癌病人化疗后单肺通气(OLV)时对病人氧合和肺内分流的影响。方法　择期手术病人 30例 ,ASAⅠ～Ⅲ级 ,随机分为对照组 (A组 )、CPAP 2组 (B组 )和CPAP 5组 (C组 ) ,每组 1 0例。A组在OLV期间非通气侧肺的支气管导管直接开口于大气中 ;B组OLV期间非通气侧持续给予CPAP(压力 2cmH2 O) ,C组OLV期间非通气侧持续给予CPAP(压力 5cmH2 O) ,并在平卧双肺通气 2 0min ,仰卧OLV 2 0min ,侧卧OLV2 0、4 0min和关胸双肺通气时 ,分别采取动脉血行血气分析并计算肺内分流率 (Qs/Qt)。结果在OLV后 2 0、4 0min时 ,B、C两组氧合明显高于A组 (P <0 .0 1 ) ,B、C两组Qs/Qt明显低于A组 (P<0 .0 5 ) ,B、C两组之间氧合和Qs/Qt仅在OLV后 4 0min时差异显著。结论　化疗后病人非通气侧持续CPAP ,有助于提高氧合 ,减少肺内分流 ,减少低氧血症的发生率 ,且CPAP 2cmH2 O更易为临床所接受     

小潮气量联合呼气末正压对单肺通气肺内分流及炎性反应的影响

目的研究单肺通气（OLV）时小潮气量联合呼气末正压（PEEP）对肺内分流及炎性反应的影响。方法食管癌根治术患者60例,年龄20～65岁,随机均分为三组,OLV时患者V_T均为6ml/kg,PEEP分别为0cmH₂O（A组）、5cmH₂O（B组）和10cmH₂O（C组）。记录患者气道压变化,采集桡动脉血和深静脉血行血气分析并计算氧合指数（OI）和肺内分流率（Qs/Qt）,采集外周静脉血进行炎性因子检测。结果与双肺通气30min时比较,三组OLV30、60、90min时Qs/Qt、肿瘤坏死因子α（TNF-α）、T₂、T₃时A、C组白细胞介素-8（IL-8）明显增高（P<0.05）,但B组Qs/Qt、IL-8显著低于A、C组（P<0.05）。A、C组OLV30、60、90min时OI较双肺通气30min时明显降低（P<0.05）;B组仅在OLV30min时降低（P<0.05）。与A、C组比较,B组OLV30、60、90min时IL-10显著增高（P<0.05）。结论 OLV中V_T6ml/kg联合PEEP5cmH₂O可以降低Qs/Qt,减轻炎性反应,改善氧合。     

急性等容血液稀释对犬单肺通气期间肺分流与氧合的影响

目的 观察犬单肺通气期间，不同程度急性等容血液稀释对肺分流和氧供、氧耗等的影响。方法 12只健康杂种犬，基础麻醉后插入双腔气管导管，股动、静脉置管。稳定30分钟（HD0）后，以血定安等速置换全血，分别达到轻度（HD1）、中度（HD2）、重度（HD3）和极重度（HD4）血液稀释四个阶段。每阶段均分为双肺通气（TLV）和单肺通气（ OLV），分别于各阶段TLV、OLV15分钟后测量分流（Qs/Qt)及氧供（DO2）、氧耗（VO2）等各指标变化。结果 随着HD程度的加深，平均动脉压、心输出量、肺血管阻力（PVR）、平均肺动脉压（MPAP）、氧分压、DO2等趋于降低，氧摄取率（EPO2）、血乳酸、Qs/Qt趋于增加，到HD3、HD4时已出现DO2－VO2依赖性降低及无氧酵解征象。与TLV时相比，OLV期间HD0、HD1及HD2组PVR、MPAP增高明显（P＜0．01）。而HD3、H4D4组变化不大（P＞0．05） ；OLV时QS／Qt增加更为明显，HD2、HD3及HD4组分别较基值增加74％、164％及177％（P＜0．01） 。结论 缺氧、ANHD均为影响Qs/Qt与氧合的重要因素，OLV时ANHD应以不低于中度为准。     

雾化吸入前列腺素E1对急性肺损伤猪氧合及肺内分流的影响

目的 探讨雾化吸人前列腺素E1（PGE1）对急性肺损伤（ALI）猪氧合及肺内分流的影响。方法 18头健康家猪，腹腔注射戊巴比妥钠50mg/kg，气管内插管机械通气，持续静脉输注氯胺酮100mg、2％普鲁卡因100ml、氯化琥珀胆碱100mg混合液维持麻醉。记录平均动脉压（MAP）、平均肺动脉压（MPAP）、动脉血氧分压（PaO2）、动脉血二氧化碳分压（PaCO2）、肺顺应性（Cdyn）、心排出量（CO），计算动静脉分流值（Qs／Qt）、肺血管阻力（PVR）和体循环阻力（SVR）作基础值，经气管导管向肺内注入0．1mol／L盐酸溶液，至PaO2〈100millHg并持续30min为ALI模型成功，记录上述指标。动物随机分为A、B、C三组，每组6头。A组机械通气，B组机械通气，呼气末正压（PEEP），C组机械通气PEEP，雾化吸人PGE1。观察4h，每1h记录上述指标一次。结果 ALI成功后，三组MAP均降低，但组间差异无统计学意义（P〉0．05）；三组MPAP升高，C组与A、B组比较差异有统计学意义；C组PaO2较A、B组升高；C组Cdyn高于A组；C组CO高于A组；三组Qs／Qt升高，C组低于A、B组；C组PVR低于A组（P〈0．05）。结论 雾化吸人PGE1能降低盐酸致ALI猪的氧合，改善肺气体交换，减少肺内分流。     

帕瑞昔布钠对食管癌根治术患者单肺通气时肺内分流的影响

目的 探讨帕瑞昔布钠对食管癌根治术患者单肺通气(OLV)时肺内分流的影响.方法 择期行食道癌根治术患者45例,年龄47～57岁,体重42～59kg,ASA分级Ⅰ或Ⅱ级,随机分为2组:生理盐水组(C组,n=23)和帕瑞昔布钠组(P组,n=22).P组静脉注射帕瑞昔布钠40 mg(生理盐水稀释至10 ml),C组静脉注射等容量生理盐水.随后两组均靶控输注异丙酚(效应室靶浓度4μg/m1)和舒芬太尼(效应室靶浓度0.3 ng/ml)行麻醉诱导,静脉注射罗库溴铵0.9 mg/kg,光纤支气管镜引导下插入双腔气管导管,行机械通气.于麻醉诱导开始后30 min(T0)、单肺通气15 min(T1)、30 min(T2)、1 h(T3)、恢复双肺通气30 min(T4)和1 h(T5)时测定CVP、HR、MAP和气道平均压(Pmean),同时采集颈内静脉和桡动脉血样,进行血气分析,计算肺内分流率(Qs/Qt).结果 与T0时比较,两组T1-3时Pmean 和Qs/Qt升高(P＜0.05);与T1时比较,两组T2.3.时Qs/Qt降低(P＜0.05);两组各时点Pmean、Qs/Qt、CVP、HR和MAP比较差异无统计学意义(P＞0.05).结论 帕瑞昔布钠40 mg对食管癌根治术患者单肺通气时缺氧性肺血管收缩反应无影响.     

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.