术侧肺部分通气法与单肺通气的比较研究

Objective The purpose of this study was to compare oxygenation and airway pressure during partial ventilation of the independent lung( PLV) with one-lung ventilation(OLV). Methods 16 patients undergoing thoracotomy for esophageal carcinoma were randomized divided into two groups and a self -controlled cross -over study was used. Two types of ventilation was used in different sequence after two-lung ventilation(TLV), oxygenation index( OI) and airway pressure was compared between groups. Results OI was significantly lower during OLV and PLV than TLV, while it was significantly higher during PLV than OLV (PLV391±112, OLV134±53, TLV530±92,P<0.05). Airway pressure was also significantly lower during PLV than OLV[Ppeak: (19±3) cm H20 vs(27±5) cm H2O,Pplat: (17±2) cm H2O vs (23±3) cm H20, P<0.05 ]. Conclusion PLV significantly improve oxygenation and respiratory mechanics.     

术侧肺部分通气法与单肺通气的比较研究

Objective The purpose of this study was to compare oxygenation and airway pressure during partial ventilation of the independent lung( PLV) with one-lung ventilation(OLV). Methods 16 patients undergoing thoracotomy for esophageal carcinoma were randomized divided into two groups and a self -controlled cross -over study was used. Two types of ventilation was used in different sequence after two-lung ventilation(TLV), oxygenation index( OI) and airway pressure was compared between groups. Results OI was significantly lower during OLV and PLV than TLV, while it was significantly higher during PLV than OLV (PLV391±112, OLV134±53, TLV530±92,P<0.05). Airway pressure was also significantly lower during PLV than OLV[Ppeak: (19±3) cm H20 vs(27±5) cm H2O,Pplat: (17±2) cm H2O vs (23±3) cm H20, P<0.05 ]. Conclusion PLV significantly improve oxygenation and respiratory mechanics.     

Narcotrend在老年人喉罩全麻纤支镜检查中的应用

目的 观察Narcotrend在老年人喉罩全麻纤支镜检查中应用的可行性,寻求检查中最适宜的Narcotrend指数(narcotrend index,NTI). 方法 60例择期行喉罩全麻纤支镜检查的老年患者,采用随机数字表法分为3组(每组20例),其中Ⅰ组:NTI(79～65)组、Ⅱ组:NTI(64～37)组、Ⅲ组:NTI(＜37)组,监测各时间点的NTI、无创收缩压(systolic blood pressure,SBP)、舒张压(diastolic blood pressure,DBP)、平均动脉压(mean arterial pressure,MAP)、血氧饱和度(blood oxygen saturation,SpO2)、心率(heart rate,HR)和呼气末二氧化碳分压(end-tidal carbon dioxide partial pressure,PETCO2);记录置喉罩后达到靶NTI的时间及丙泊酚用量、苏醒时间、定向力恢复时间、副作用等. 结果 置喉罩后丙泊酚用量Ⅰ组(2.16±0.31) mg/kg、Ⅱ组(2.78-0.37) mg/kg、Ⅲ组(3.15±0.29)mg/kg,组间差异有统计学意义(P＜0.05).Ⅰ组进镜顺利率为85％,其余两组为100％.各组间SBP、DBP、MAP和HR差异有统计学意义(P＜0.05),且Ⅲ组有2例患者出现低血压及心动过缓.Ⅲ组苏醒时间及定向力恢复时间较Ⅰ组和Ⅱ组延长(P＜0.05). 结论 Narcotrend可监测老年患者麻醉镇静深度,指导调控丙泊酚用量,老年患者喉罩全麻纤支镜检查的适宜NTI为64～37.     

小潮气量肺保护性通气策略与压力通气模式对妇科腹腔镜手术患者氧合功能的影响

目的:评价小潮气量肺保护性通气策略(protective lung ventilation mode,PLV)与压力通气模式(pressure con-trolled ventilation,PCV)在妇科腹腔镜手术中应用的有效性及安全性。方法:拟于我院择期行妇科腹腔镜手术的患者共计144例,按随机序列号分为PLV组和PCV组,每组72例。PLV组潮气量6 ml/kg,吸呼比1∶2,呼吸频率16次/min,呼气末正压5 cmH 2O(1 cmH 2O=0.098 kPa);PCV组设定通气压力维持潮气量8 ml/kg,吸呼比1∶2,呼吸频率12~16次/min。分别于气管插管后5 min(T1)、气腹后10 min(T2)、气腹后20 min(T3)、撤除气腹后10 min(T4)记录患者气道峰压(airway peak pressure,Ppeak)、平均气道压(mean airway pressure,Pmean),并计算动态肺顺应性(dynamic lung compliance,Cdyn)。于T3、T4时点行血气分析记录PaO 2、PaCO 2、肺泡-动脉氧分压差(alveoli-arterial oxygen partial pressure,A-aDO 2),并计算氧合指数(oxygenation index,OI)。结果:PLV组T3时点Ppeak、Pmean显著高于PCV组,但Cdyn低于PCV组,差异有统计学意义(P<0.05)。PLV组T4时点Ppeak显著高于PCV组,差异有统计学意义(P<0.05)。两组T2、T3时点Ppeak、Pmean较T1时点显著升高,而Cdyn显著低于T1时点,差异有统计学意义(P<0.05)。PLV组T3时点Ppeak、Pmean显著高于T2时点,Cdyn显著低于T2时点,差异有统计学意义(P<0.05)。PLV组T3时点PaO 2、OI显著高于PCV组,而PaCO 2、A-aDO 2显著低于PCV组,差异有统计学意义(P<0.05)。两组T4时点PaO 2、OI较T3时点显著升高,而PaCO 2、A-aDO 2较T3时点显著降低,差异有统计学意义(P<0.05)。两组T4时点PaO 2、PaCO 2、A-aDO 2、OI差异无统计学意义(P>0.05)。两组间各呼吸系统并发症发生情况及住院天数差异均无统计学意义(P>0.05)。结论:对妇科腹腔镜手术患者而言,PCV有助于维持患者呼吸动力学稳定,而小潮气量PLV有助于维持患者术中氧合功能,二者安全性差异无统计学意义。     

支气管封堵器用于胸腔镜肺大疱切除术中的有效性和安全性研究

目的 通过与双腔支气管导管对比,研究支气管封堵器(bronchial blockers tube,BB)在胸腔镜肺大疱切除术中应用的有效性和安全性. 方法 肺大疱患者80例,按随机数字表法分为2组(每组40例):双腔支气管导管组(A组)和BB组(B组),A组采用双腔支气管导管,B组采用BB.比较两组患者的一般资料、插管情况,并比较麻醉后即刻(T0)、单腔通气后20min(T1)、单腔通气后60 min(T2)、恢复双腔通气后60 min(T3)时点的血气分析情况及副作用的发生情况. 结果 B组一次插管成功率高于A组,差异有统计学意义(P＜0.05).T1、T2时两组患者的动脉血氧分压(arterial blood partial pressure of oxygen,PaO2)低于T0和T3时,且T2时低于T11,差异均有统计学意义(P＜0.05);T11T2时B组患者的PaO2高于A组,差异有统计学意义(P＜0.05).两组患者各时点的动脉血二氧化碳分压(arterial blood partial pressure of carbon dioxide,PaCO22比较,差异无统计学意义(P＞0.05).与T0和T3时比较,两组患者T11T2时气道平台压(airway plateau pressure,Pplat)、气道峰压(peak airway pressure,Ppeak)均升高,且B组患者Ppeak和Pplat低于A组,差异有统计学意义(P＜0.05).A组患者术后有11例出现声音嘶哑和咽痛,发生率为27.5％,而B组为3例,发生率为7.5％,两组比较差异有统计学意义(P＜0.05). 结论 BB用于胸腔镜肺大疱切除术中是一种安全、有效的方式.     

二氧化碳充气在妇科术后无痛结肠镜检中的安全性研究

目的 比较妇科手术后行结肠镜检查中注入空气与二氧化碳(carbon dioxide,CO2)的效果. 方法 选取我院妇科手术后行常规无痛结肠镜检查患者62例,采用随机数字表法分为C02组和空气组(每组31例),结肠镜检查中分别注入C02、空气.记录两组患者结肠镜检查成功率、操作时间、丙泊酚用量、恢复时间及检查后不同时间的腹痛程度,比较检查前后HR、MAP、Sp02、经皮二氧化碳分压(transcutaneous carbon dioxide partial pressure,PtcC02)的变化,VAS评估检查后15 min、1h、3h、6h及24 h腹痛程度. 结果 两组患者检查成功率、操作时间、丙泊酚用量和恢复时间差异无统计学意义(P＞0.05);两组患者检查前、检查中及检查后HR、MAP、Sp02、PtcCO2差异无统计学意义(P＞0.05);C02组患者检查后15 min、1h、3h、6h、24 h时点VAS评分均显著低于空气组[(21.6±9.5)分比(46.7±14.1)分、(14.4±5.4)分比(32.6±9.6)分、(9.1±3.6)分比(22.9±8.4)分、(4.3±1.1)分比(9.7±3.5)分、(2.3±1.1)分比(4.1±1.9)分](P＜0.05). 结论 妇科术后患者行无痛结肠镜检查时注入CO2代替空气安全有效,且能减轻检查后腹痛程度.     

全麻腹腔镜胃癌根治术中应用小潮气量联合低水平呼气末正压通气对老年患者呼吸功能的影响

目的:观察全身麻醉腹腔镜胃癌根治术中应用小潮气量(tidal volume,VT)联合低水平呼气末正压通气(positive end expiratory pressure,PEEP)对老年患者呼吸功能的影响。方法:将34例ASA I或II级腹腔镜胃癌根治术老年患者分为A、B两组。A组:机械通气模式为间歇正压通气(intermittent positive pressure ventilation,IPPV)加5cm H2O PEEP,VT=6ml/kg,f=16次/min;B组:机械通气模式为IPPV,VT=9ml/kg,f=12次/min。观察术前(T1)、麻醉插管后30min(T2)、拔管后15min(T3)的动脉氧分压(PaO2)、动脉二氧化碳分压(PaCO2)、呼气末二氧化碳分压(PETCO2)、肺泡-动脉氧分压差(A-aDO2)、平均动脉压(mean arterial pressure,MAP)、中心静脉压(central venous pressure,CVP)及术中的气道峰压(peak airway pressure,Ppeak)。结果:T3时,A组PaO2明显高于B组(P<0.05),A组A-aDO2明显低于B组(P<0.05)。其他各时点A、B两组PaO2、PaCO2、PETCO2、A-aDO2、MAP、CVP、Ppeak组间比较差异无统计学意义(P>0.05)。结论:腹腔镜胃癌根治术中应用小VT联合低水平PEEP通气能有效改善老年患者术后低氧血症,减少肺部并发症,有利于老年患者呼吸功能的恢复,对血流动力学无明显影响,是老年患者腹腔镜上腹部手术全麻安全、有效的通气方法。     

Changes of dipalmitoyl phosphatidyl choline after mechanical ventilation in patients with acute cerebral injury

Objective: To detect the levels of dipalmitoyl phosphatidyl choline (DPPC) in the sputum of the patients with acute cerebral injury without primary pulmonary injury after mechanical ventilation treatment. Methods: DPPC levels in sputum of 35 patients with acute cerebral injury but without pulmonary injury were detected with high performance liquid chromatography at the beginning of ventilation and 16-20 days, 21-40 days, and 41-60 days after ventilation, respectively. Results: There was no significant difference of the DPPC levels between 16-20 days after ventilation (3.36±0.49) and at the beginning of ventilation (3.37±0.58) (P>0.05). The mean levels of DPPC decreased significantly at 21-40 days (2.87 mg/ml±0.26 mg/ml, P < 0.05) and 41-60 days (1.93 mg/ml±0.21 mg/ml, P < 0.01) after ventilation compared with that at the beginning of ventilation. At the same period, the peak inspiratory pressure and the mean pressure of airway increased significantly, whereas the static compliance and the partial pressure of oxygen in artery decreased significantly. Among the 25 patients who received ventilation for more than 20 days, 8 (32%) had slightly-decreased partial pressure of oxygen in artery compared with that at the beginning of ventilation. Conclusions: Mechanical ventilation can decrease the DPPC levels, decrease the lung compliance and increase the airway pressure, even impair the oxygenation function in patients with acute cerebral injury. Abnormal DPPC is one of the major causes of ventilator-associated lung injury.     

不同麻醉方法用于老年患者纤支镜检查的临床研究

目的 探讨不同麻醉方法用于老年患者纤支镜检查的效果与安全性.方法 将40例需行纤支镜检查的老年患者随机分成无痛纤支镜(S)组和常规纤支镜(C)组两组.每组20例患者.S组采用异丙酚、舒芬太尼麻醉,C组采用2%利多卡因雾化喷喉,分别观察两组检查前、检查中及检查后的脉搏血氧饱和度(pulse oxygen saturation,SpO2)、收缩压(systolic blood pressure,SBP)、舒张压(diastolic blood pressure,DBP)、心率(heart rate,HR)变化及副作用.结果 S组麻醉后患者能在无知觉和无痛苦中接受检查,出现呛咳、憋气、及体动等副作用少,血压(blood pressure,BP)、HR变化与C组相比相对稳定,均低于C组(P<0.05).结论 采用异丙酚复合小剂量舒芬太尼麻醉用于老年患者纤支镜检查可充分减轻患者的痛苦,患者无挣扎,手术操作顺利,循环稳定,并发症少,是一种安全而有效的麻醉方法.     

腹腔高压对急性坏死性胰腺炎血流动力学影响的动物实验研究

目的 评价腹腔高压状态对急性坏死性胰腺炎模型猪血流动力学的影响.方法 在12只家猪胰管内注射含5%牛磺胆酸钠和0.5%胰蛋白酶的生理盐水1 ml/kg,制作急性坏死性胰腺炎模型.模型随机分为两组(n=6),一组采用氮气气腹法制作30 mmHg(1 mmHg=0.133 kPa)腹腔高压模型,持续12 h(腹腔高压组);另一组未暴露于腹腔高压(胰腺炎组).利用动脉导管和血流导向气囊导管动态监测平均动脉压、心排血量、中心静脉压、肺动脉压、肺动脉楔压等血流动力学指标并行血气分析检查.观察腹腔高压对胰腺炎猪血流动力学的影响.结果 腹腔高压组1只猪在造模后11 h死亡,另11只持续观察12 h.与胰腺炎组相比,腹腔高压组在3、6和12 h时,心率、中心静脉压、平均肺动脉压和肺动脉楔压上升;12 h时心排血量、平均动脉压明显下降(P均<0.05).制模前两组气道峰压无差异,制模后腹腔高压组气道峰压在6 h和12 h时分别达(50.2±3.1)cmH2O(1 cmH2P=0.098 kPa)和(49.8±0.9)cmH2O,明显高于胰腺炎组(P<0.01).腹腔高压组6 h和12 h时的pH值、氧分压、中心静脉血氧饱和度及碱剩余较胰腺炎组明显下降,血乳酸和二氧化碳分压则明显上升(P均<0.05).结论 腹腔高压对急性坏死性胰腺炎模型猪的血流动力学产生明显影响,及时采用合适的方式减轻、解除腹腔高压是胰腺炎治疗的重要环节之一.

Abstract：

Objective To assess the effect of infra-abdominal hypertension (IAH) on hemodynamics of severe acute pancreatitis (SAP) in porcine model. Methods Following baseline registrations, SAP was induced in 12 animals. The N2 pneumoperitoneum was used to increase the intra-abdominal pressure to 30 mmHg (1 mmHg = 0. 133 kPa) in 6 of 12 SAP animals thereafter and keep constant during the experiment. The investigation period was 12 h. Heart rate, cardiac output (CO), central venous pressure (CVP) , mean arterial pressure and pulmonary arterial wedge pressure (PAWP)were continuously measured with the aid of balloon tipped flow-directed catheter and electrocardiography monitor. Oxygen partial pressure of artery (PaO2) , carbon dioxide partial pressure of artery (PaCO2) , ScvO2, base excess (BE) , and blood lactic acid (LAC) were measured by acid-base analysis. Results In the IAH group, CO decreased significantly at 12 h, CVP and PAWP increased significantly at 3 h, 6 h and 12 h compared with SAP group (all P < 0. 05). Peak inspiration pressure increased immediately after pneumoperitoneum in the IAH group, to (50. 2±3. 1) cmH2O(1 cmH2O =0. 098 kPa) and (49. 8±0. 9) cmH2O at 6 h and 12 h respectively. The pH, PaO2, ScvO2 and BE showed a tendency to fall in the IAH group. PaCO2 and LAC were increased significantly in the IAH group (all P < 0. 05). Conclusions There were remarkable and relatively irreversible effects on global hemodynamics in response to sustained IAH of 12 h with the underlying condition of SAP. Abdominal decompression is beneficial for patients of SAP with IAH.     

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.     

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.     

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.