体外循环心内直视手术期间乌司他丁对心肌缺血/再灌注损伤的保护作用

目的 评价乌司他丁对先天性心脏病心内直视手术围体外循环期心肌缺血／再灌注损伤的保护作用。方法 选择20例房间隔缺损或室间隔缺损修补术病人，随机分为对照组（C组）与乌司他丁组（U组），每组10例。分别于体外转流前（T1）、开放主动脉即刻（T2）、开放主动脉30min（T3）、停止CPB 4h(T4)和24h(T5)抽取动脉血，测定血浆CK－MB、CK活性及cTnI浓度。记录CPB转机时间、主动脉阻断时间、手术时间、围CPB期间心血管活性药物的使用情况、心脏复跳情况以及术后24h引流量。结果 两组病人术前血浆cTnI浓度及CK、CK－MB活性无关 正常范围内，组间比较无差异。C组血浆cTnI浓度在T3、T4和T5时点都显著升高（P＜0．01），于T4时点达峰值，T5时点开始下降。U组血浆cTnI浓度在T3、T4时点显著升高（P＜0．01），于T5时点已下降至正常水平。在T3－T5时点U组cTnI水平明显低于C组（P＜0．05）。C组与U组血浆CK和CK－MB活性在T2－T5时点都显著升高（P＜0．01），T2－T4时点两组比较无显著性差异，至T5时点U组显著低于C组（P＜0．05）。U组自动复跳率多于C组（P＜0．05）。术后24h引流量C组明显多于U组（P＜0．05）。结论 围CPB期间分两次使用乌司他丁1．2万U／kg，能减轻心肌缺血／再灌注损伤。     

乌司他丁对心脏直视术中缺血-再灌注损伤的保护作用

目的：研究乌司他丁对心肺转流（CPB）心脏直视手术中缺血－再灌注损伤的保护作用。方法：20例择期CPB心脏瓣膜手术患者随机均分为对照组（C组）和乌司他丁组（U组），C组不给药，U组给予乌司他丁100万U（其中30万U为麻醉诱导前给予，40万U预充体外循环机内，30万U为开放升主动脉后给予），分别于麻醉诱导后（T1），阻断升主动脉30分钟（T2），再灌注1小时（T3），再灌注2小时（T4）及再灌注3小时（T5）各时间点取静脉血用ELISA法测定样本中下降各指标的水平。肿瘤坏死因子－α（TNF-α），白细胞介素－6（IL－6），白细胞介素－8（IL－8）。结果：两组血清中TNF－α，IL-6，IL－8的浓度，都是在再灌注后与手术前值及阻断主动脉30分钟的值相比有明显的增加（P＜0．05），在T3，T4，T5三个时点C组的TNF－α，IL－6，IL－8的释放明显低于对照组（P＜0．05），结论：在CPB过程中乌司他丁可以通过抑制炎性介质TNF－α，IL－6和IL－8的释放而减轻缺血－再灌注损伤。     

乌司他丁对心肺转流心脏手术病人脑氧代谢的影响

目的探讨乌司他丁对心肺转流（CPB）心脏手术病人脑氧代谢的影响。方法选择24例择期行心脏瓣膜置换术病人,随机分为乌司他丁组（U组）和对照组（C组）,每组12例。U组共给予乌司他丁2．4万U／kg,其中1．2万U／kg于麻醉诱导后静脉推注,0．6万U／kg加入CPB预充液中,随转流进人体内,0．6万U／kg于主动脉开放前约5min加入CPB机内。C组用等量的生理盐水代替。于麻醉后手术前（T1）、低温稳定期（T2）、复温至36℃（Ts）、CPB结束后60min（Tt）、CPB结束后6h（T5）同时抽取动脉血与颈静脉球血,进行血气分析和动脉血、颈静脉球血乳酸（AL、VL）测定并计算动脉血氧含量（CaO2）、动脉-颈内静脉血氧含量差（Ca-jvO2）、脑乳酸生成量（AVDL）与乳酸氧指数（LOI）。结果C组Ca-jvO2于T2至T5、U组于T2至T4均有不同程度降低（P〈0．05）;两组AL、VL于T2至T5进行性升高,AVDL、LOI于T4、L高于T1至L3两组间CaO2各时点无显著性差异;U组颈静脉球血氧饱和度（SjvO2）、AL、VL、AVDL、LOI于T4、T5时明显低于C组（P〈0．05或P〈0．01）;U组Ca—jvO2于T4、T5时明显高于C组（P〈0．05或P〈0．01）。结论乌司他丁可以减轻CPB引起的脑无氧代谢,改善脑氧摄取与利用。     

小剂量氯胺酮对体外循环促炎细胞因子反应及心肌损伤的影响

目的 探讨小剂量氯胺酮对体外循环（CPB）诱发的促炎细胞因子反应及心肌损伤的影响。方法 20例择期瓣膜替换术病人,随机分成氯胺酮组（n＝10）和对照组（n＝10）。氯胺酮组于麻醉诱导和转流开始时按1mg.kg^-1静注氯胺酮,对照组则采用等量生理盐水注射。分别于术前（T1）、CPB60min（T2）、CPB结束后2h（T3)、4h(T4)及24h（T5）各时间点测定动脉血中下列各项指标;肿瘤坏死因子－α（TNF－α）、白细胞介素－6（IL－6）、白细胞介素－8（IL－8）、血浆过氧化脂质（LPO）、心肌肌酸酶同工酶（CK－MB）。结果 与术前（T1）比较,两组TNF－α、IL－6、IL－8、LPO、CK－MB均明显升高（P＜0．05或0．01）;但氯胺酮组T2－T5TNF－α、IL－6、IL－8浓度、T3LPO浓度和T3、T4、CK－MB活性均显著低于对照组（P＜0．05）。结论 小剂量氯胺酮能有效抑制CPB诱发的促炎细胞因子反应和心肌损伤。     

乌司他丁对体外循环心脏手术患者肺炎性反应的影响

目的 研究乌司他丁（ulinastatin,uti)对心肺转流（CPB）心脏手术患者肺炎性反应的影响。方法 择期心脏瓣膜置换患者60例，随机分成对照组（I组，n=20),uti 1万U／kg组（Ⅱ组,n=20),uti 2万U／kg组（Ⅲ组,n=20)。在CPB前主动脉开放心脏复跳1、3、5、10min分别采右心房与肺静脉血检测PMN、CD11b、IL－8、IL－10、MDA和SOD水平。结果 主动脉开放心脏复跳后对照组右心房和肺静脉血中上述指标的水平较CPB前显著性升高（P＜0．05），与对照组比较，乌司他丁两组肺静脉血上述指标的水平明显下降（P＜0．05）。结论 （1）体外循环过程中肺发生了炎性反应；（2）乌司他丁能减轻CPB肺部的炎性反应，其2万U／kg组抑制炎性反应的效果优于1万U／kg组。     

乌司他丁和抑肽酶对体外循环小儿炎性反应及心肌损伤的影响

目的研究乌司他丁和抑肽酶对体外循环（CPB）小儿炎性反应及心肌损伤的影响。方法选择拟行CPB的先天性心脏病患儿90例,随机分成6组,每组15例：对照组（C组,不使用乌司他丁及抑肽酶）、小剂量乌司他丁组（UL组,乌司他丁1万U/kg）、大剂量乌司他丁组（UH组,乌司他丁2万U/kg）、小剂量抑肽酶组（AL组,抑肽酶7．5万KIU/kg）、大剂量抑肽酶组（AH组,抑肽酶15万KIU/ kg）、小剂量乌司他丁复合小剂量抑肽酶组（UL＋AL组,乌司他丁1万U/kg＋抑肽酶7．5万KIU/kg）。乌司他丁或/和抑肽酶按各组要求剂量在转机前一次性加入预充液中。于CPB前（T1）、升主动脉开放5 min（T2）、CPB结束后30 min（T3）、4 h（T4）抽取动脉血,测定血浆IL-6、IL-8、IL-10、TNF-α、cTnI浓度及CK-MB活性,记录术后辅助通气时间、24 h引流量、心脏复跳情况及围术期多巴胺使用情况。结果与C组比较,在T2～T4时,UH组、AH组、UL＋AL,组血浆IL-6、IL-8、TNF-α、cTnI浓度及CK-MB活性降低;AH组、UL＋AL组IL-10增高（P＜0．05）;UL＋AL组心脏自动复跳率（100％）增高,血管活性药物使用率较低,术后辅助通气时间较短（P＜0．05）;AH组术后出血量较少（P＜0．05）。结论大剂量乌司他丁、大剂量抑肽酶及小剂量乌司他丁复合小剂量抑肽酶,均可通过抑制CPB炎性反应、减轻小儿心肌损伤,小剂量乌司他丁复合小剂量抑肽酶效果更佳。     

乌司他丁改善维持性血液透析患者微炎症及氧化应激状态

目的观察乌司他丁对维持性血液透析（MHD）患者微炎症和氧化应激状态的影响。方法选取我院行MHD治疗的患者51例，随机分为MHD对照组（M组）和乌司他丁治疗组（U组），U组患者于每次透析结束后静脉滴注乌司他丁20万U，共12周。同时设立健康对照组（C组）。分别于治疗前后检测患者血清高敏C反应蛋白（hs—CRP）、肿瘤坏死因子-α（TNF-α）、白介素-6（IL-6）以及血浆丙二醛（MDA）、谷胱甘肽过氧化物酶（GSHPx）。结果①与C组相比，M组和U组治疗前hs—CRP、TNF-α、IL-6和MDA水平均明显升高（P〈0．01）；GSHPx水平下降（P〈0．01）；②U组治疗12周后与治疗前相比，hs—CRP、TNF-α、IL6和MDA水平均明显下降（P〈0．05或P〈0．01），GSHPx水平增高（P〈0．01）；③在治疗12周后，U组hs—CRP、TNF-α、IL-6和MDA水平较M组降低（P〈0．05或P〈0．01），而GSHPx水平增高（P〈0．01）。结论以上结果提示乌司他丁可改善MHD患者微炎症及氧化应激状态。     

心肺转流心脏手术用乌司他丁对肾功能的影响

目的研究乌司他丁对心肺转流（CPB）心脏手术患者。肾功能的影响。方法30例拟行心脏瓣膜置换手术患者,分为两组,每组各15例。对照组未用药（C组）,实验组乌司他丁（U组）。实验组（U组）给予乌司他丁2万U／kg,体外循环前静脉滴入1／3量,体外循环机内预充1／3量,开放升主动脉后给予1／3量。术后第1、2、3天分别静脉输注乌司他丁0．5万U/kg,对照组（C组）给予等量生理盐水。分别于术前（T0）、术后1d（T1）、3d（T3）、5d（T5）、7d（T7）检测血清尿素氮（BUN）、血清肌酐（Cr）、血清β2-微球蛋白（β2-MG）、尿视黄醇结合蛋白（RBP）、尿β2-微球蛋白（β2-MG）的含量。结果①BUN、Cr：C组术后T1和T3显著高于术前及U组同一时点值（P〈0．05）;②血清β2-MG：C组术后仅T1、T3明显高于术前及U组同一时点值（P〈0．05）;③尿RBP：C组术后各时点值及U组T1、T3值明显高于术前值（P〈0．01）,两组术后各时点比较,U组明显低于C组（P〈0．01）;④尿β2-MG：C组术后各时点值显著高于术前值（P〈0．01）,U组T1、T3明显高于术前值（P〈0．05）,两组间术后各同一时点值比较有统计学差异（P〈0．01）。结论乌司他丁对心肺转流（CPB）心脏手术后患者。肾功能有一定保护作用。     

乌司他丁对体外循环心脏手术后病人肾功能的影响

目的 观察乌司他丁对体外循环(CPB)心脏手术后病人肾功能的影响。方法 24例择期心脏瓣膜替换术病人随机分成对照组(C组，n=12)和药物组(U组，n=12)；药物组术中予乌司他丁(UTI)30万U注入预充液中随机转入体内，术后1～3d均予UTI 30万U静滴。对照组予等量生理盐水。分别于术前(T0)、术后ld(T1)、3d(T3)、5d(T5)、7d(T7)检测尿中视黄醇结合蛋白(RBP)、尿中N-乙酰-β-D-氨基葡萄糖苷酶(NAG)、尿中β2-微球蛋白(β2-MG)、血清β2-MG、血清肌酐(Cr)、血清尿素氮(BUN)。结果①尿RBP：C组术后各时点值以及U组T1、T3值明显高于T0值(P＜0．01、P＜0．05)，两组术后各时点值比较，U组明显低于C组(P＜0．01)；②尿NAG：C组术后各时点值显著高于T0(P＜0．01)，U组术后各时点值逐渐升高，T5、T7与T0比较差异有显著性(P＜0．05、P＜0．01)，两组间术后各时点值比较差异有显著性(P＜0．01)；③尿β2-MG：C组术后各时点值显著高于T0值(P＜0．01)，U组T1、T3明显高于T0值(P＜0．05)，两组间术后各同一时点值比较差异有显著性(P＜0．01)；④血β2-MG：C组术后仅T3明显高于T0值及U组同一时点值(P＜0．05)；⑤BUN、Cr：C组术后仅T2、T3显著高于T0及U组同一时点值(P＜0．05)。结论 UTI对CPB心脏手术后病人肾脏功能具有保护作用。     

乌司他丁对不停跳冠状动脉搭桥术围术期促炎性细胞因子的影响

目的　观察乌司他丁对心脏不停跳冠状动脉搭桥术(OPCABG)患者围术期血浆促炎性细胞因子代谢水平的影响。方法　22 例行 OPCABG患者随机分为两组:乌司他丁组(U组),切皮前(麻醉诱导后)将乌司他丁12 kIU·kg 1·h 1稀释至100 ml生理盐水中持续静脉输注;对照组(C组),以等量生理盐水代替。分别于切皮前(T1)、切开心包时(T2)、旁路血管开放时(T3)及术毕(T4)抽取静脉血采用放免法测定血浆白细胞介素 6(IL- 6)、白细胞介素 8(IL -8)及肿瘤坏死因子α(TNF- α)浓度。结果　C组IL 6浓度在手术开始后T2~T4 时段均较T1 明显升高(P<0 05);U组IL 6浓度较对照组明显降低(P<0 .05);U组IL 8和TNF -α在T2~T4 时段较对照组显著降低(P<0. 05)。结论　心脏OP -CABG术中应用乌司他丁能显著抑制IL 6、IL- 8、TNF -α等促炎性细胞因子的释放。     

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.     

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.     

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.     

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.