婴儿深低温体外循环术后肺表面活性物质的变化

目的 比较婴儿先天性心脏病在深低温停循环(DHCA)或深低温低流量(DHLF)下行心内直视手术后肺表面活性物质(PS)活性水平的变化. 方法 根据采用的体外循环(CPB)方法不同,将20例室间隔缺损伴肺动脉高压的婴儿分为DHCA组和DHLF组,每组10例.测定CPB前,CPB结束5分钟和2小时时PS活性水平的饱和卵磷脂/总磷脂(SatPC/TPL)和饱和卵磷脂/总蛋白(SatPC/TP)值和肺静态顺应性. 结果 DHLF组术后住ICU时间明显长于DHCA组(P<0.05), DHLF组术后SatPC/TPL、SatPC/TP和肺静态顺应性下降的幅度均明显大于DHCA组(P<0.01). 结论 DHLF较DHCA更能引起PS活性水平的降低,从而引起更严重的肺损伤.     

体外循环下心脏矫治术中地氟醚-NO对先心病合并肺动脉高压患儿肺的保护作用

目的 探讨体外循环下心脏矫治术中吸入地氟醚-NO对先心病合并肺动脉高压患儿肺的保护作用。方法 40例先心病合并肺动脉高压患儿随机分为4组（n=10）：对照组（CON组）、地氟醚组（DES组）、NO组（NO组）及地氟醚＋NO组（DES＋NO组）。DES组在肺动脉导管置入后吸入地氟醚1～1．3MAC直至转流前（约40min），NO组在相同时段吸入10～20ppmNO，DES＋NO组在相同时段吸入地氟醚与10～20ppmNO。在开胸后5min（T0）、转流前5min（T1）、转流开始后5min（T2）以及手术结束时（T1）各时点分别记录患儿的平均动脉压（MAP）、肺动脉压（PAP）、气道峰压（Ppeak）和呼吸系统总顺应性（Crs），在T0、T3时点分别抽取动脉血测定高铁血红蛋白（MetHb）、血浆可溶性细胞粘附分子（sICAM-1）和丙二醛（MDA）浓度以及黄嘌呤氧化酶（XOD）活性。结果 与T0相比，T1-3时NO组和DES＋NO组PAP降低；L时CON组Ppeak升高，Crs及PaO2降低（P〈0．01），DES组PaO2降低但Ppeak、Crs差异均无统计学意义，NO组和DES＋NO组Ppeak、Crs和PaO2差异均无统计学意义。与CON组相比，L时N0组和DES＋NO组Ppeak降低，Crs及PaO2增高（P〈0．05）。与L相比，L时CON组sICAM-1、XOD和MDA水平均升高；T1时DES组、NO组和DES＋NO组上述指标均低于CON组。结论 在体外循环下心脏矫治术中，先心病合并肺动脉高压患儿转流前吸入地氟醚与NO，不仅可降低肺动脉压，还可通过抑制全身炎性反应及脂质过氧化反应，减轻肺损伤。     

中度高海拔地区开胸手术对肺泡表面活性物质的影响

目的探讨中度高海拔地区开胸手术对肺泡表面活性物质(PS)的影响。方法收集2013年9月至2015年4月在青海省人民医院胸外科经左胸行食管癌根治术胸内吻合术患者21例,分别于手术前后行左、右肺支气管肺泡灌洗,测定支气管肺泡灌洗液(BALF)中PS的活性水平,包括饱和卵磷脂(SatPC)、总磷脂(TCP)、总蛋白(TP)。以右侧肺为对照组,并以饱和卵磷脂/总磷脂(SatPC/TPL)比值和饱和卵磷脂/总蛋白(SatPC/TP)比值作为判断PS活性的指标。结果术前左、右侧肺BALF中的SatPC/TPL分别为(48.75±14.39)%和(48.76±12.90)%,SatPC/TP分别为(10.88±2.24)%和(11.78±2.24)%,差异均无统计学意义(t=-0.0024,P0.05;t=-1.3019,P0.05)。术后左侧肺的SatPC/TPL为(26.15±9.81)%,明显低于右侧的(47.62±12.58)%;术后左侧肺的SatPC/TP为(5.34±2.54)%,也显著低于右侧的(10.15±2.28)%,差异均有统计学意义(t=6.1674,P0.01;t=6.4579,P0.01)。左侧肺术后与术前BALF中的SatPC/TPL分别为(26.15±9.81)%和(48.75±14.39)%),SatPC/TP分别为(5.34±2.54)%和(10.88±2.24)%,差异均有统计学意义(t=5.9467,P0.01;t=7.4964,P0.01)。右侧肺术后与术前BALF中的SatPC/TPL分别为(47.62±12.58)%和(48.76±12.90)%,SatPC/TP分别为(10.15±2.28)%和(11.78±2.24)%,差异均无统计学意义(t=0.2889,P0.05;t=2.3370,P0.05)。结论在中度高海拔地区开胸手术对于患者术侧肺功能造成一定损伤,使PS活性明显下降;对非术侧肺功能不造成损伤,对PS活性无明显影响。     

p38 MAPK在机械通气所致肺损伤中的作用

目的 研究P38丝裂原激活蛋白激酶（P38 MAPK）在机械通气所致肺损伤中的作用。方法 15只普通健康80日龄家猪,随机分为3组:A组（VT=16ml/kg,PEEP=0）,B组（VT=6Ml/kg,PEEP=16cm H2O）和 C组（VT=6 ml/kg,PEEP=8cm H2O）。机械通气3h后在光镜下观察肺组织的病理学改变,并采用免疫组化检测肺组织ICAM-1的表达水平、Western Blot法测定肺组织p38MAPK及磷酸化p38MAPK的含量。结果 光镜下A、B两组有明显肺组织损伤,C组则无明显肺损伤表现。A、B两组肺泡上皮、肺间质及肺血管内皮细胞ICAM-1表达均呈阳性,C组肺组织ICAM-1表达阴性。三组间肺组织中未磷酸化P38MAPK含量无显著性差异（P>0.05）,而A、B两组肺组织的磷酸化p38 MAPK含量显著高于C组（P<0.05）。结论 大VT或小VT高PEEP可导致急性肺损伤,P38 MAPK介导了炎症反应所致的急性肺损伤。     

压力-容积曲线指导下单一PEEP用于侧切口先天性心脏病手术对呼吸功能的影响

目的观察较低潮气量（VT）联合适当呼气末正压（PEEP）通气对侧切口矫治先天性心脏病术中患儿呼吸功能的影响。方法 54例1～5岁先天性心脏病房（室）间隔缺损患儿,心功能Ⅰ或Ⅱ级,所有患儿均采用右外侧小切口矫治房（室）间隔缺损。联合组（Ⅰ组）V_T7～8ml/kg,根据动态压力-容积（P-V）曲线目测其呼气支上拐点（最大曲率点PMC）对应的压力P_PMC设置PEEP。对照组（Ⅱ组）VT10ml/kg,PEEP为0。于侧卧位切皮前（T₁）、心肺转流（CPB）前5min（T₂）、缝皮后即刻（T₃）分别记录患儿生命体征、呼吸力学指标并行动脉血气分析。结果与Ⅱ组比较,T₁～T₃时Ⅰ组气道峰压（Peak）、平台压（Plat）、平均气道压（Pmean）均降低,T₂、T₃时Ⅰ组肺泡动态顺应性（Cdyn）升高（P<0.05）;T₂时Ⅰ组动脉血氧分压（PaO₂）升高,肺泡-动脉血氧分压差[P（A-a）DO₂]、呼吸指数（RI）降低（P<0.05）。结论在侧切口矫治先天性心脏病术中较低V_T（6～8ml/kg）,结合适当PEEP可有效的降低术中气道压,改善Cdyn,增加肺通气与氧合效率,有利于肺保护。     

抑制PAI-1对大鼠左心疾病所致肺高压的影响

目的 探讨纤溶酶原激活物抑制剂1（PAI-1）的抑制剂IMD-1622用于治疗左心疾病所致肺高压（PH-LHD）大鼠的效果。方法 SD1月长鼠40只,采用随机数字表法均分为四组：对照组（C组）、假手术组（S组）、模型组（M组）和抑制剂组（I组）,每组10只。C组,不做任何处理;S组,麻醉后吸氧,经左侧2～3肋间侧开胸,然后关胸;M组,制作PH-LHD模型;I组,PH-LHD模型建模成功后腹腔注射IMD-1622 20mg/kg。 四组大鼠给予正常实验室饮食和水喂养至8周后,监测CVP、MAP、平均肺动脉压（MPA）、左心房压（LAP）,计算肺血管阻力（PVR）和体循环阻力（SVR）;取肺组织切片测量肺动脉中膜层厚度;HE染色免疫组化检测PAI-1含量;免疫荧光法检测肺组织中内皮素1（ET-1）及血栓素A2（TXA2）含量。结果 M组和 I组MPA、LAP、PVR明显高于C组和S组,M组明显高于I组(P<0.05)。M组和I组肺动脉中膜层厚度明显厚于C组和S组,M组明显厚于I组（P<0.05）。M组和I组肺组织PAI-1含量组化灰度分析数值均明显高于C组和S组,M组明显高于I组（P<0.05）。M组和I组肺组织中ET-1和TXA2荧光表达明显强于C组和S组,M组明显强于I组（P<0.05）。结论 PAI-1抑制剂IMD-1622可以减轻肺动脉中膜层增厚,改善左心疾病所致肺高压。     

利用动态肺顺应性设定呼气末正压在胸腔镜肺叶切除术中的运用

目的 探讨单肺通气利用动态肺顺应性设定呼气末正压通气(positive end-expiratory pressure,PEEP)的优势及可行性. 方法 选择预行右侧肺叶切除患者80例,完全随机分为A组和B组,每组40例:A组,单肺通气实施肺膨胀(sustained inflation,SI)复张后加用20 cmH2O(1 cmH2O=0.098 kPa)的PEEP并递减滴定,随后以得到最大肺顺应性的PEEP值通气,直到恢复双肺通气;B组,通气PEEP值固定为5 cmH2O,其他通气方法同A组.记录患者血气、呼吸等参数. 结果 两组设定的PEEP值[A组(9.2±1.2) cmH2O,B组5 cmH2O]差异有统计学意义(P＜0.05);在单肺通气1 h(T3)、手术结束(T4)时,两组动脉血氧分压(partial pressure of oxygen,PaO2)比较,差异有统计学意义(P＜0.05);B组的PaO2在T3～T4逐步降低,差异有统计学意义(P＜0.05),而A组则维持较好(P＞0.05);T3、T4时刻A组的动态肺顺应性[(30.8±5.9)、(30.7±6.4) ml/cmH2O]与B组[(26.6±5.5)、(26.4±5.2) ml/cmH2O]比较,差异有统计学意义(P＜0.05). 结论 胸腔镜肺叶切除术中的单肺通气,利用动态肺顺应性设定的PEEP值通气能够得到更好的氧合及呼吸参数,并且维持较好.     

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。     

不同通气模式对老年患者腹腔镜结直肠手术呼吸参数的影响

目的观察小潮气量容量控制通气(VCV)联合呼气末正压通气(PEEP)和压力控制通气(PCV)联合PEEP对老年患者呼吸参数的影响。方法选择行腹腔镜直肠、乙状结肠手术患者51例,男25例,女26例,年龄65~80岁,BMI 18~30kg/m2,ASAⅠ或Ⅱ级,随机分为两组:VP组(VCV+PEEP)和PP组(PCV+PEEP),每组25例。气腹期间VP组以VT6 ml/kg+5cmH2O PEEP模式通气,PP组将VT设为6 ml/kg通气3 min后切换为PCV并加用5cmH2O PEEP进行通气。记录气管插管VCV通气5min(T1)、建立人工气腹5 min(T2)、建立人工气腹35min(T3)、建立人工气腹65min(T4)、手术结束(T5)、拔管前(T6)时VT、动态肺顺应性(Cdyn)、RR、气道峰压(Ppeak)、气道平台压(Pplat)和PETCO2。记录T1、T3、T4和离开PACU(T7)时PaO2、PaCO2,并计算肺泡-动脉血氧分压差(PA-aDO2)、氧合指数(OI)、呼吸指数(RI);记录术后5d内肺部并发症(PPCs)情况。结果与VP组比较,T2-T4时PP组VT明显升高、Cdyn明显增大(P0.05),T3-T5时PP组RR明显减慢(P0.05),T2-T5时PP组Ppeak和Pplat明显降低(P0.05),T4时PP组PETCO2和PA-aDO2明显降低、PaO2明显升高、RI明显减小、OI明显增大(P0.05)。术后随访两组患者PPCs差异无统计学意义。结论PCV联合PEEP通气模式明显降低Ppeak和Pplat、增高VT和增大Cdyn,同时明显改善气腹65min时肺氧合功能,所以老年患者腹腔镜结直肠手术术中应优先考虑使用。     

幼猪机械通气中异氟醚或七氟醚混合一氧化氮吸入的安全性

目的研究吸入异氟醚或七氟醚混合一氧化氮(NO)在幼猪机械通气中的安全性。方法36头幼猪随机分为6组:Ⅰ组(对照组):单纯机械通气;Ⅱ组(NO组):吸入20ppmNO;Ⅲ组(异氟醚组):吸入1.3MAC异氟醚;Ⅳ组(异氟醚 NO组):吸入1.3MAC异氟醚及20ppmNO;Ⅴ组(七氟醚组)吸入1.3MAC七氟醚;Ⅵ组(七氟醚 NO组)吸入1.3MAC七氟醚及20ppmNO。用麻醉机行间歇正压通气4h,测定各组机械通气前、机械通气1、2、3、4h(T0、T1、T2、T3、T4)的呼吸频率(RR)、呼吸系统总顺应性(Crs)、气道压力(Paw)、潮气量(VT)、分钟通气量(MV)以及呼末二氧化碳分压(PETCO2);测定T0、T2、T4时点动脉血高铁血红蛋白(MetHb)和亚硝酸根(NO2-/NO3-)水平;处死动物后比较各组肺组织湿/干重比、支气管肺泡灌洗液(BALF)中饱和磷脂/总磷脂(DSPC/TPL)及饱和磷脂,总蛋白(DSPC/TP)、肺表面张力和白细胞计数,并行肺组织损伤评分。结果Ⅲ、Ⅳ、Ⅴ、Ⅵ组BALF中DSPC/TP及肺表面张力较Ⅰ组下降(P<0.05),通气结束时Crs较通气前下降(P<0.05),而Ⅱ组无显著性变化(P>0.05);与通气前比较,各组通气结束时MetHb与:NO2-/NO3-水平无变化,各组BALF中白细胞计数、肺组织损伤评分、肺泡扩张度和湿/干重比之间比较差异无统计学意义。结论1.3MAC异氟醚或七氟醚混合20ppmNO吸入可以安全用     

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.