右美托咪定镇痛作用的临床研究进展

背景 疼痛是困扰人类最严重的临床问题之一.在临床上,右美托咪定(dexmedetomidine,Dex)广泛应用于术前、术中和术后镇静、镇痛. 目的 探讨Dex用于围手术期镇痛是否具有显著优势. 内容 Dex具有良好的超前镇痛或辅助镇痛、稳定血流动力学、延长麻醉药的镇痛时间、降低围手术期副作用等作用,尤其是一些特殊患者的围手术期应用,如产科麻醉和小儿麻醉. 趋向 Dex围手术期镇痛最佳的用药时机、方法以及患者的选择尚需更多的研究去证实.     

右美托咪定在心血管手术麻醉中的应用价值和进展

背景右美托咪定(dexmedetomidine,Dex)是高选择性α2肾上腺素能受体激动剂,具有镇静、镇痛、抗焦虑及抑制交感和应激反应的作用,已广泛应用于临床麻醉,近期研究表明Dex在心血管手术麻醉中有一定的应用价值.目的 阐述Dex在心血管手术麻醉中应用的适用性、有效性和安全性,为临床应用提供参考.内容概述Dex在心血管手术麻醉围手术期具有的稳定血流动力学、抗心律失常、器官保护、防治术后谵妄和抗炎作用以及副作用的防范.趋向Dex在心血管手术麻醉中有一定的应用价值,但需要进一步研究明确Dex的临床应用范围、副作用及处理措施,以便更好地应用于临床.     

右美托咪定与产科麻醉镇痛相关的研究及探讨

背景目前国内关于右美托咪定(dexmedetomidine,Dex)用于产科临床研究相对较少,然而越来越多的研究结果显示Dex在产科麻醉镇痛方面具有独特优势.目的 对近年来Dex应用于产科麻醉镇痛的相关研究进行介绍,并进一步探讨.内容Dex已被证实可安全应用于新生儿全身麻醉而无或极少有副作用,同时不少临床研究报道证实了其减少七氟醚和氯胺酮引起毒性反应的作用.Dex已被用于产科静脉复合麻醉及蛛网膜下腔麻醉.在这些应用中,Dex体现出了减轻围产期寒战、恶心呕吐,维持全身麻醉剖宫产正常宫缩的作用.Dex较轻的呼吸抑制作用和可唤醒镇静使之适用于产科清醒插管;然而Dex在产科麻醉镇痛方面的用药目前仍属超说明书范围用药,用药指南仍需更多的临床研究得以实现.趋向为优化产科麻醉与镇痛提供新的药物选择.     

右美托咪定的药物相互作用

背景 右美托咪定(dexmedetomidinne,Dex)是一种高选择性的α2肾上腺素能受体激动剂,兼具有镇静、镇痛、降低交感神经张力等作用,同时无呼吸抑制和脑电干扰等副作用,现已广泛应用于临床.大量研究表明Dex和麻醉药物之间存在药物相互作用. 目的 综述国内外Dex和麻醉药物在药代学和药效学上的相互作用研究,为临床合理应用提供参考. 内容 探讨Dex与麻醉药物之间相互作用所产生的临床效应,如减少麻醉药物用量、减少药物副作用的发生率、稳定血流动力学等,并探讨其发生的相关机制. 趋向 随着研究的不断深入,期望Dex能在临床应用中得到更广泛的应用.     

右美托咪定给药途径的研究进展

背景 右美托咪定(dexmedetomidine,Dex)是一种新型高选择性α2肾上腺素能受体激动剂,具有镇静、镇痛、抗焦虑及抗交感等作用,在临床上应用已很广泛,其给药途径也趋于多样化. 目的 对有关Dex的论著进行归纳总结,以探讨其给药方式的应用前景. 内容 阐述Dex复合局部麻醉药应用于椎管内、外周神经及关节腔的安全性以及对局部麻醉药作用效果的影响,评价通过静脉注射、口服、肌内注射、皮下、鼻腔及直肠等途径给药的安全性及有效性. 趋向 Dex给药途径多样化在临床应用中具有广阔的前景.     

右美托咪定在焦虑、抑郁、睡眠障碍中的研究进展

右美托咪定(Dex)是一种高度选择性的α2肾上腺素能受体(α2-AR)激动剂, 具有独特的镇静、镇痛、抗交感作用, 被广泛用于临床麻醉和重症监护治疗病房。近年来的研究发现Dex还具有调节负面情绪、改善睡眠障碍、保护神经系统等作用, 且成瘾性较弱, 有望成为治疗精神障碍的潜在药物。文章将重点讨论Dex在焦虑、抑郁、睡眠障碍中的应用, 探讨其在精神病学领域中的潜在价值, 为临床精神障碍的治疗提供新的思路。     

右美托咪啶的临床麻醉应用进展

背景 右美托咪啶为高效、高选择性的α2肾上腺素受体激动剂,具有镇静、镇痛和抗焦虑等作用.自1999年美国FDA批准将其用于ICU的镇静以来,其在临床麻醉中的应用也日益广泛.目的 综述右美托咪啶在临床麻醉中的应用进展,为该药在临床工作中的应用提供参考.内容 此文分别从作用机制及临床应用两方面,综述了右美托咪啶的镇静作用,镇痛作用,抑制术中应激反应,麻醉辅助作用及对术后恢复的影响等内容.趋向 右美托咪啶作为新型的麻醉辅助用药,其在临床麻醉中的应用具有广泛前景.     

地塞米松减轻曲马多术后镇痛引起恶心呕吐的观察

如何在提高曲马多镇痛效果的同时，减轻其不良反应，已引起临床的关注。本研究采用随机双盲和对照方法探讨应用地塞米松(Dex)对减轻曲马多术后镇痛引起恶心呕吐的临床效果。     

右美托咪定复合氯胺酮在小儿麻醉中应用的研究进展

背景 右美托咪定(dexmedetomidine,Dex)是一种高选择性的α2肾上腺素受体激动剂,在小儿麻醉中的应用尚处于研究阶段.氯胺酮作为N-甲基-D-天冬氨酸受体拮抗剂,是小儿麻醉的常用药物.近年来,一些研究者将Dex复合氯胺酮用于小儿麻醉,取得了良好的临床效果. 目的 梳理Dex复合氯胺酮在小儿麻醉中应用的研究进展,为临床应用提供参考.内容 概述Dex和氯胺酮的药代动力学,以及两者复合麻醉在小儿患者创伤性检查、术前、术中以及困难气道处理中的应用.趋向 Dex复合氯胺酮在小儿麻醉中具有广阔的应用前景.     

右美托咪定心脏保护作用的研究进展

背景 右美托咪定（dexmedetomidine,Dex）是高选择性α2肾上腺素能受体激动剂,具有镇静、镇痛、降低交感神经张力等作用,同时无呼吸抑制及脑电干扰等副作用,现已广泛应用于重症监护病房（ICU）及围术期辅助镇静。近期研究发现Dex具有心脏保护作用,如抗缺血/再灌注损伤（ischemia/repeffusion injury,I/RI）、抗心律失常等。 目的 对Dex心脏保护作用的研究进展作一综述,为其合理应用提供参考。内容 介绍Dex对心脏的保护作用及其相关机制。 趋向 深入研究Dex心脏保护作用及其机制有望改善相关患者的预后。     

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.