左心转流降主动脉瘤手术中致萎陷肺损伤因素的临床研究

为探讨左心转流降主动脉瘤手术中致萎陷肺出血的因素，作者对１４例手术中萎陷肺有不同程度出血（Ａ组）和１４例手术中无肺出血（Ｂ组）的临床资料进行了回顾性分析。结果表明：Ａ、Ｂ两组在转流量、上肢血压及ＣＶＰ存在显著性差异，而在年龄、体重、左心转流时间及主动脉阻断时间、瘤体大小及肺粘连等方面无明显区别，但两组均未测左房压。鉴于上述发现，作者在Ｃ组（８例）进行了前瞻性临床研究，即维持每分钟转流量３５±３．１ｍｌ／ｋｇ，通过调节左房引流控制左房压在０．６７～２．００ｋＰａ（５～１５ｍｍＨｇ），结果Ｃ组即无肺出血发生，也无明显肺组织病理学改变。作者认为左心转流降主动脉瘤手术期间维持转流量大于每分钟３０ｍｌ／ｋｇ，控制左房压在上述范围，可保证合适的肺循环和体循环血流动力学，防止萎陷肺损伤。     

上腔静脉综合征的外科治疗

目的报告５例上腔静脉综合征外科治疗经验及体会。方法２例行颈内静脉－大隐静脉转流术，３例行颈外静脉－大隐静脉转流术。结果无术后并发症及手术死亡。术后近期疗效满意５例，远期疗效满意２例。结论外科手术治疗上腔静脉综合征能明显改善患者的预后；但由于上腔静脉综合征病因、梗阻部位和范围不同，手术方法应有所选择。     

改良迷宫手术治疗二尖瓣疾病伴慢性心房颤动

目的介绍一种治疗二尖瓣疾病伴慢性心房颤动的改良迷宫手术。方法对１５例作二尖瓣替换手术的患者同时施行改良迷宫手术，常规建立体外循环及心肌保护。房顶和房间隔联合切口完成后作绕肺静脉口的环形切口。－６０℃，２分钟冷冻环形切口左下至二尖瓣后瓣环中点及环形切口左上至左心耳开口之间的区域。连续缝合环形切口，替换二尖瓣。连续缝合左房顶和房间隔，开放主动脉后关闭右心房切口及切除左心耳。结果所有患者术后均康复出院。除二尖瓣替换外尚有５例行左心房血栓清除，３例行三尖瓣环缩。出院随访１～５月（平均３月），１５例患者均恢复为窦性心律。结论与ｍａｚｅ－Ⅲ手术相比我们所采用的改良迷宫手术技术较为简便，亦安全可行，但其长期效果需进一步观察     

复杂动脉导管未闭的外科治疗

在近１０多年中，作者单位收治复杂动脉导管未闭６９例，其中窗型９例、动脉瘤型１３例、粗大动脉导管１５例、假性动脉瘤３例、动脉导管钙化３例、动脉导管再通５例、有导管炎史５例、合并重度肺动脉高压１６例。单纯结扎导管５１例、加垫卷或垫片结扎导管９例、左心转流下切断导管缝合５例、对导管或主动脉破裂出血，采用补片修补结扎导管２例、带环涤纶人造血管套入胸主动脉内结扎２例。术后早期死亡２例（２．９％）。随访５个月～１６年，手术效果满意，杂音均消失。作者认为，良好的手术效果取决于对困难动脉导管未闭不同类型，采用了不同的手术方法，强调对破裂的动脉导管或主动脉进行补片修补或带环涤纶人造血管套入胸主动脉内结扎术，操作简便，安全可靠。     

左心转流在胸部降主动脉瘤手术中的应用

目的探讨左心转流在降主动脉瘤手术治疗中的应用。方法11例降主动脉癌患者,均行左心转流降主动脉人工血管置换术。结果全部患者的治疗效果均十分满意,1例术后胸腔出血并肺部感染,经再次开胸止血,联合应用抗生素和全身支持治疗后痊愈,其余患者均无并发症发生。结论左心转流下行胸部降主动脉瘤手术是积极安全有效的。     

胸主动脉夹层的外科治疗

目的总结胸主动脉夹层(AD)的外科治疗经验。方法1993年至2003年4月手术治疗A型AD40例，B型20例，其中急性夹层16例。A型采用中度低温体外循环13例，深低温停循环(DHCA)和上腔静脉逆灌(RCP)27例；行升主动脉置换24例，升主动脉和半弓置换11例，升主动脉、全弓和象鼻手术5例；同期行Bentall手术18例，主动脉瓣置换8例，冠状动脉旁路移植术1例。B型采用左心转流7例，股一股转流2例，DHCA 11例；行近端降主动脉置换14例，全胸降主动脉置换或伴肋间动脉移植6例。结果全组术后死亡率10％(急性夹层18．8％，慢性夹层6．8％)，近3年降至4．4％。术后并发呼吸功能不全8例，二次开胸止血3例，延迟性心包压塞和腹腔内出血各2例，声音嘶哑3例。结论正确掌握手术指征、手术技巧和术中脑保护是手术治疗AD的关键。A型夹层的手术范围应依据内膜破裂口位置决定。     

分期手术治疗混合型布加氏综合征

我们为９例肝静脉和下腔静脉混合阻塞型布加氏综合征施行了分期手术。３例行带囊导管扩张术，１～２周后行脾切除、脾肾静脉分流、贲门周围血管离断联合手术；２例行下腔静脉切开成形术，１个月后行脾切除、脾肾静脉分流、贲门周围血管离断联合手术；４例行下腔静脑右心房人造血管转流术，１个月后行脾切除、脾肾静脉分流、责门周围血管离断联合手术。随访６个月至２年，效果良好。     

左心转流半身体外循环用于主动脉缩窄手术两例

左心转流半身体外循环用于主动脉缩窄手术两例金新会作者单位：８１００１２西宁市，青海省高原医学科学研究所麻醉科我院１９９４年采用左心转流半身体外循环，手术治疗主动脉缩窄并动脉导管未闭两例，术后恢复良好，报告如下。例１．男性，２０岁，６０ｋｇ，运动性心慌...     

主动脉缩窄的诊断和外科矫正

外科矫正主动脉缩窄２１例。术前漏诊３例。手术分别在浅低温、左心转流、体外循环或常温下进行，共采用８种术式。结果：ｌ８例术后上、下肢压差消失。２１例均痊愈出院，随访１～８年，仅２例成年病人仍有高血压。结论：上肢高血压而下肢低血压或存在差异性发绀者应疑诊本病。病人应于学龄前接受手术。多数可常温阻断主动脉行矫正术，术后应药物控制高血压。     

主动脉瘤的外科治疗

主动脉瘤常发生在升主动脉、主动脉弓、胸部降主动脉、胸腹主动脉、腹主动脉。国外报道其相对发生率分别为１０％、７％、１６％、２％和６５％。我们于１９９３年８月～１９９８年４月行手术治疗１２例,疗效良好。１　临床资料与方法１１　一般资料　本组共１２例,男１１例,女１例。年龄２７～７８岁,平均５４岁。升主动脉瘤５例,胸降主动脉瘤２例,胸腹主动脉瘤１例,腹主动脉瘤４例;其中真性动脉瘤６例,假性动脉瘤１例,夹层动脉瘤５例。在５例主动脉夹层动脉瘤中,ＤｅＢａｋｅｙⅡ型２例,ＤｅＢａｋｅｙⅢ型３例。６例真性…     

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.     

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.     

Is the recovery profile of mivacurium independent of the rate of decay of its plasma concentration in patients with normal plasma cholinesterase activity?

Background: The duration of action of muscle relaxants is poorly correlated to the rate of decay of their plasma concentration. The plasma concentration of mivacurium may rapidly decrease below its active concentration because of the extensive hydrolysis of mivacurium. By inflating a tourniquet on one upper limb for 3 min after the administration of atracurium, mivacurium or vecuronium, we studied the influence of the initial decline of their plasma concentration on their effect. Methods: In 50 patients anaesthetised with thiopental, isoflurane and fentanyl, the effect of bolus doses of 0.15 or 0.25 mg . kg^?1 mivacurium (MIV 15, MIV 25), 0.3 or 0.5 mg . kg^?1 atracurium (ATR 30, ATR 50) and 0.06 or 0.1 mg . kg^?1 vecuronium (VEC 06, VEC 10) were measured on both arms (evoked response of the adductor pollicis to train-of-four stimulation every 12 s), a tourniquet being applied on one arm just before and during 3 min after the muscle relaxant bolus. Results: Tourniquet inflation of 3 min almost abolished the neuromuscular effect of mivacurium. In the vecuronium groups and in the ATR 50 group, tourniquet inflation did not modify the maximum degree of depression of the twitch response. Also, the duration of action of vecuronium was unaffected by the tourniquet. In the ATR 30 group, times to return of the twitch response to 25% (duration 25%) and 75% (duration 75%) of control response were significantly shorter in the cuffed arm, 23 min vs 27 min, and 41 min vs 45 min, respectively. In the ATR 50 group, only duration 25% was significantly shorter in the cuffed arm (41 min vs 45 min). Conclusion: The results suggest that the rate of decline of the plasma concentration of mivacurium is so rapid, that a very low and almost clinically ineffective concentration is present as soon as 3 min after its administration. The results also indicate that the recovery from a mivacurium-induced neuromuscular blockade is not influenced by the rate of decay of its plasma concentration in patients with genotypically normal plasma cholinesterase.     

Membranes in Artificial Organs

Abstract: Membrane processes play a pivotal and enabling role in modern replacement therapy for acute and chronic organ failure and in the management of immunologic diseases. In fact, virtually all contemporary extracorporeal blood purification methods employ membrane devices, and the next generation of artificial organs and tissue engineering therapies are almost certain to be similarly grounded in membrane technology. In this short essay, we comment on the similarities and differences among synthetic membranes and their natural counterparts and also provide a critical overview of the demographics and technology of hemodialysis, hemofiltration, apheresis, oxygenation, and emerging membrane technologies and applications.     

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.     

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.