“烟囱”支架在急性期锚定区不足的Stanford B型主动脉夹层中的应用体会

目的:探讨应用胸主动脉腔内修复术（thoracic endovascular aotic repair,TEVAR）治疗急性期锚定区不足假腔未血栓化的Stanford B型主动脉夹层时“烟囱”支架重建左锁骨下动脉（left subclavian artery,LSA）的治疗效果。方法:回顾性分析2013年2月至2021...     

Ankura主动脉覆膜支架行原位开窗重建弓上分支的应用

背景与目的 胸主动脉腔内修复术（TEVAR）已经成为治疗主动脉弓部病变的首选术式。然而,此术式要求支架近端安全锚定区至少为15 mm,对于锚定区不足者,则通常需重建弓部分支血管以确保手术安全。在目前各种重建技术中,原位开窗技术因其较大程度的保留分支血管以及较低的内漏风险而应用最多。因此,本研究探讨Ankura主动脉覆膜支架进行原位开窗重建弓上分支的可行性及效果。方法 回顾性分析2017年3月—2020年12月中国科学院大学宁波华美医院收治的47例近端锚定区不足的主动脉病变患者的临床资料。其中胸主动脉夹层38例,胸主动脉瘤6例,胸主动脉溃疡3例。根据术前CTA影像资料决定患者的开窗数目、开窗支架规格,术中利用穿刺针对Ankura主动脉覆膜支架进行原位开窗重建弓部分支,术后定期行主动脉CTA复查随访。结果 所有患者均获手术成功,共植入Ankura胸主动脉覆膜支架47枚,Gore Viabahn覆膜支架51枚,Cordis Smart裸支架20枚。4例术中转烟囱支架植入,原位开窗成功率91.5%（43/47）,包括左锁骨下动脉（LSA）开窗29例,左颈总动脉（LCCA）开窗+LSA栓塞1例,LSA开窗+左椎动脉烟囱1例,LSA开窗+左LCCA烟囱9例,LCCA+LSA开窗+无名动脉（IA）烟囱1例,LCCA开窗+IA烟囱+LSA栓塞2例。全组患者手术时间160~300 min,平均（200±20）min,术中开窗时间18~45 min,平均（30±8）min;术后内漏（1型）3例,逆撕2例（1例行升主动脉置换后好转,1例死亡）,脑梗死2例,截瘫0例。平均随访时间（28.4±14.7）个月,期间2例内漏在随访中消失,1例内漏未进一步增大予以观察随访中,未见开窗分支血管闭塞。结论 利用穿刺破膜技术对Ankura主动脉覆膜支架进行原位开窗重建分支血管是一种切实可行且有效的治疗方式,近期效果良好。     

胸主动脉腔内修复术中封闭左锁骨下动脉安全性的Meta分析

目的荟萃分析胸主动脉腔内修复术(TEVAR)中左锁骨下动脉(LSA)封闭的并发症发生率以及血管重建LSA的并发症发生率,分析TEVAR术封闭LSA的转归。方法检索2009年1月1日至2016年2月1日的相关文献,对纳入研究的对象进行分组和评价,并用软件Review Manager 5.3进行统计分析。结果 TEVAR术中LSA封闭与未封闭的患者术后颅内神经症状的发生率差异无统计学意义(P0.05);封闭之后脊髓缺血发生率呈现上升趋势;TEVAR术中选择LSA封闭患者术后左上肢缺血的发生率高于LSA未封闭组,差异有统计学意义(P0.05);TEVAR术中封闭LSA选择血管重建患者术后颅内神经症状的发生率低于封闭LSA选择不重建组,差异有统计学意义(P0.05)。结论TEVAR术中封闭LSA不增加术后颅内神经症状,但增加脊髓缺血的风险;封闭LSA对左上肢血流动力学有影响,能够引起左上肢无力,麻木或不对称的冰冷等症状,但没有引起不可逆的缺血性损害;LSA血管重建能降低封闭LSA术后出现的颅内神经症状的并发症发生率。     

单分支主动脉覆膜支架修复伴锚定区不足的急性Stanford B型夹层：附8例报告

背景与目的 单分支型主动脉覆膜支架及其传输系统是近年国内研发的新型支架系统,适用于锚定区不足的主动脉夹层,是累及左锁骨下动脉（LSA）主动脉夹层的新选择。笔者通过总结使用该支架系统行胸主动脉覆膜支架腔内隔绝术（TEVAR）治疗锚定区不足的急性Stanford B型的病例,评估其近期效果与安全性。方法 回顾性收集2019年4月—2020年1月,在云南省阜外心血管病医院血管外科采用Castor^?一体化分支型主动脉覆膜支架行TEVAR的Stanford B型夹层伴锚定区不足的8例患者的临床资料。分析手术过程及围手术期并发症情况。结果 8例患者中,男7例（87.5%）,女1例（12.5%）;中位年龄42（33~64）岁;BMI（25.5±3.8）kg/m²。8例均成功植入支架,初始技术成功率100%,无围手术期死亡及神经系统并发症,无I型内漏。平均住院时间为（14.8±3.7）d。平均随访时间为223（60~370）d,所有主体、分支支架血管通畅、无相关I和III型内漏,无神经系统并发症,无左上肢缺血表现。结论 应用单分支覆膜支架行TEVAR治疗Stanford B型夹层伴锚定区不足是一种安全、有效的方法,中远期疗效有待随访。     

胸主动脉腔内修复术中覆盖左锁骨下动脉的回顾性分析

胸主动脉瘤和主动脉夹层是危及生命的疾病,发病1周内病死率为60％ ～ 70％[1].近年来,胸主动脉腔内修复术(TEVAR)已成为治疗胸主动脉瘤和B型主动脉夹层的重要方法.有选择性地覆盖左锁骨下动脉(LSA)是较常采用的扩大近端锚定区的方法[2],但仍存在争议.我们回顾性分析2004年5月至2012年1月TEVAR手术患者的资料,探讨LSA封堵的可行性.     

TEVAR保留弓上分支动脉血供的技术进展

<正>胸主动脉腔内修复治疗(thoracic endovascular aortic repair,TEVAR)自从1994年Dake等~([1])首次应用于胸主动脉瘤以来,因其创伤小、恢复快、效果确切等特点,已成为胸主动脉扩张性疾病的主流治疗方法。TEVAR的首要条件是在病变两端有一段≥1.5 cm的正常血管作为锚定区(见图1A)。临床上,有很大一部分病人由于病变缺乏足够的锚定区而无法行TEVAR术。Mitchell等~([2])以弓上分支动脉的     

胸主动脉腔内修复术治疗近端锚定区不良的胸主动脉钝性伤疗效评价

目的探讨胸主动脉腔内修复术(thoracic endovascular aortic repair,TEVAR)治疗覆膜支架近端锚定区不良的胸主动脉钝性伤(blunt thoracic aortic injury,BTAI)的临床疗效。方法回顾分析2007年12月-2014年12月采用TEVAR治疗的13例覆膜支架近端锚定区不良的BTAI患者临床资料。其中男10例,女3例;年龄24~64岁,平均44岁。术前影像学检查提示Stanford B型主动脉夹层7例,假性动脉瘤3例,动脉瘤1例,穿透性溃疡2例。根据支架近端锚定区Mitchell分区位置不同,单纯行覆膜支架置入覆盖左锁骨下动脉(left subclavian artery,LSA)8例;烟囱技术重建LSA 3例;烟囱技术重建左颈总动脉2例(其中1例采用弹簧圈栓塞LSA起始部以避免Ⅱ型内漏,1例采用原位开窗技术重建LSA)。结果手术均顺利完成,手术时间1~3 h,平均1.8 h;术中出血量30~200 m L,平均120 m L;住院时间7~37 d,平均15 d。无围手术期死亡、截瘫发生。13例均获随访,随访时间3~30个月,平均18个月。术中发生Ⅰ型内漏1例(7.7%),未予以特殊处理,于术后6个月自愈;1例术后3周出现穿刺部位皮下血肿,伴正中神经压迫症状,超声检查提示肱动脉假性动脉瘤并血栓形成,行肱动脉假性动脉瘤切除术,术后恢复尚可。所有患者术后未见明显胸背痛、憋气、左上肢乏力、麻木及头晕等症状;影像学检查提示主体及分支支架血流通畅;未见支架移位,无病变处扩张和破裂等;无新发死亡及细菌感染等严重并发症。结论根据Mitchell分区法设计个性化方案,采用TEVAR治疗覆膜支架近端锚定区不良的BTAI具有良好的近期临床效果,远期结果有待进一步随访。     

外分支支架和内分支支架治疗B型主动脉夹层的近期结果及计算流体力学分析

目的：评估外分支支架和内分支支架胸主动脉腔内修复术（thoracic endovascular aortic repair, TEVAR）治疗Stanford B型主动脉夹层（Stanford type B aortic dissection, TBAD）的近期结果,并通过计算流体力学（computational fluid dynamics, CFD）分析两种支架对主动脉夹层血流状态的影响。方法：收集2018年5月至2021年12月天津医科大学总医院血管外科采用外分支支架和内分支支架治疗TBAD病人的临床资料,回顾性分析两组近期治疗结果。基于两组的CT血管造影,各选取1例典型病例构建个性化的三维模型,进行流体力学数值模拟计算。对比分析手术前、后流场速度分布、壁面压力和壁面切应力（wall shear stress, WSS）参数。结果： 共纳入55例TBAD病人,其中外分支支架组49例,内分支支架组6例。两组基线资料差异无统计学意义。两组手术成功率均100%。外分支支架组41例（83.7%）和内分支支架组6例（100%）单纯重建左锁骨下动脉（left subclavical artery, LSA）。外分支支架组5例重建左颈总动脉（left common carotid artery, LCCA）联合颈锁动脉搭桥,2例重建LCCA联合LSA栓塞,1例重建LCCA联合LSA开窗。外分支支架组失访4例。两组围术期及随访期主动脉相关死亡率（P=1.000）、分支支架通畅率（P=1.000）及免于靶血管二次干预率（P=0.298）差异均无统计学意义。两组支架植入术后均显著改善夹层病变内流场紊乱,恢复正常主动脉血流形态,降低局部异常增高的WSS。内分支支架对主动脉弓部及分支血流状态的干扰较外分支明显。结论：外分支支架和内分支支架TEVAR重建LSA,治疗TBAD均有较好近期效果。外分支支架相比内分支支架解剖契合度较高,可较大程度恢复主动脉弓部正常血流状态。     

Stanford B型主动脉夹层合并迷走右锁骨下动脉的腔内治疗：附16例报告

背景与目的：迷走右锁骨下动脉（ARSA）为主动脉弓部的一种先天畸形,Stanford B型主动脉夹层（TBAD）合并ARSA是一种罕见且严重威胁患者生命的疾病。既往临床上对其处理通常采用开放手术或杂交手术。随着血管腔内技术的飞速发展,胸主动脉腔内修复术（TEVAR）已逐渐被应用与TBAD合并ARSA的治疗,并展现出其创伤小,恢复快的优势。但由于ARSA与夹层破口相对位置的不确定性,如何处理夹层破口与ARSA成为了影响其腔内治疗的主要因素,完全腔内治疗这一复杂主动脉弓部病变的安全性和有效性尚不明确。本文旨在探讨TBAD合并ARSA的腔内修复治疗方法,总结初步经验。  方法：回顾性分析2012年1月—2019年12月中南大学湘雅二医院血管外科采用TEVAR治疗的16例TBAD合并ARSA患者资料。其中男14例,女2例;平均年龄为（56.1±11.3）岁;13例患者破口位于Z3区,3例位于Z4区;左椎动脉优势14例,右椎动脉优势1例,双侧椎动脉均势1例。根据主动脉夹层破口位置与双侧锁骨下动脉开口位置、椎动脉形态制定手术方案。 结果：技术成功率100%,平均手术时间（95.2±38.9）min,无围手术期死亡。2例患者保留双侧锁骨下动脉,5例患者封堵ARSA,7例患者采用烟囱技术重建左锁骨下动脉（LSA）,1例患者采用烟囱技术重建LSA并采用潜望镜技术重建ARSA,1例患者采用开窗技术重建LSA。弓部分支动脉重建的患者,术后服用拜阿司匹林（100 mg/d）和氯吡格雷（75 mg/d）3个月。平均随访时间33.2（3~66）个月。无内漏、支架移位等;右上肢缺血2例,保守治疗后逐渐恢复;比较术前和末次随访的主动脉CTA,降主动脉最大直径从（37.1±9.6）mm降至（33.9±8.9）mm,假腔与真腔之比从1.03±0.62降至0.21±0.31。长期随访,所有烟囱支架均保持通畅,未出现弓部分支动脉缺血、锁骨下动脉窃血、脊髓缺血等症状。 结论：TEVAR辅以“烟囱”、开窗等技术治疗合并ARSA的TBAD安全可行,可以在保留LSA和（或）ARSA血流的同时良好封堵主动脉夹层破口,且创伤小、住院时间短、围手术期并发症发生率低。具体的手术方式应由夹层破口与双侧锁骨下动脉的相对位置来决定,应至少保证椎动脉优势一侧锁骨下动脉的血流供应。      

主动脉定制开窗支架治疗主动脉弓动脉瘤中国首例报告（附视频）

背景与目的：胸主动脉腔内修复术（TEVAR）治疗胸主动脉病变已逐渐成为一线手术方案。然而，受限于主动脉弓部复杂解剖结构，在治疗病变的同时如何有效重建弓部分支动脉是应用当前标准化产品常有的困境。鉴于此，笔者团队与支架厂家合作开发了Castor胸主动脉定制开窗覆膜支架（以下简称Castor定制开窗支架），并实施了国内首例Castor定制开窗支架的置入。本文对此作一汇报。方法：报告国内首例Castor定制开窗支架置入病例的临床资料、支架定制情况与手术过程，并进行Castor定制开窗支架的优缺点分析与相关文献复习。结果：患者为59岁男性，于TEVAR术后14年发生主动脉弓部动脉瘤，病变累及左侧锁骨下动脉（LSA）、左颈总动脉（LCCA）。经患者及家属同意后采用Castor定制开窗支架隔绝动脉瘤，手术规划拟采用Castor定制开窗支架隔绝动脉瘤，将Castor支架分支置入LCCA；术前定制开窗分别重建无名动脉（IA）和LSA。术中成功置入Castor单分支支架并顺利重建弓部三根分支动脉，术后复查结果提示动脉瘤隔绝满意无内漏，弓部三根分支动脉通畅，同时无主动脉相关不良事件的发生。结论：Castor...     

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.