再谈甲状腺手术喉返神经损伤的相关因素

喉返神经损伤是甲状腺手术的常见并发症之一,会严重影响病人的生活质量。但喉返神经损伤并非仅与术中操作有关。其影响因素很多,涉及解剖、病例特点、围手术期评估、术中操作、手术范围、能量器械应用、术中神经监测技术（IONM）应用等。坚持充分的术前评估、制定合理的手术计划和切除范围、术中精细被膜解剖、正确合理应用能量器械、规范使用IONM,能够最大程度减少喉返神经损伤,提高病人术后生活质量。     

甲状腺手术中喉返神经保护研究进展

喉返神经损伤是甲状腺手术中常见的并发症之一.随着超声刀、术中神经监测、腔镜甲状腺切除术、精细化解剖技术等设备仪器和治疗理念的广泛推广,在甲状腺手术方式发生巨大改变的同时,术中保护喉返神经也面临新的问题.熟悉喉返神经的解剖特点,掌握新技术、新器械、新仪器的使用技巧,是在新技术和新理念应用中保护喉返神经的关键.     

甲状腺术中解剖喉返神经783例

目的：探讨甲状腺手术中解剖喉返神经对防止喉返神经损伤的价值。方法：对783例甲状腺手术病例,术中解剖喉返神经405例,不解剖喉返神经378例,观察术后喉返神经损伤情况。结果：解剖喉返神经组喉返神经暂时性损伤2例,损伤率0.49%,无永久性损伤病例。不解剖喉返神经组喉返神经损伤11例,损伤率2.91%,其中永久性损伤6例,暂时性损伤5例。结论：甲状腺手术中解剖喉返神经,能显著减少喉返神经的损伤,是预防其损伤的有效方法。     

甲状腺手术中解剖喉返神经的临床研究

目的探讨甲状腺手术中解剖喉返神经对防止喉返神经损伤的价值。方法回顾性分析783例甲状腺手术患者的临床资料,术中解剖喉返神经405例（解剖组）,不解剖喉返神经378例（不解剖组）,观察术后两组喉返神经损伤情况。结果解剖喉返神经组喉返神经暂时性损伤2例,损伤率0.49%,无永久性损伤病例。不解剖喉返神经组喉返神经损伤11例,损伤率2.91%,其中永久性损伤6例,暂时性损伤5例。两组间差异有统计学意义（P〈0.01）。结论甲状腺手术中解剖喉返神经能显著减少喉返神经的损伤,是预防其损伤的有效方法。     

甲状腺手术中喉返神经的显露方法及疗效研究

目的 分析甲状腺手术中喉返神经的显露对预防喉返神经损伤的效果.方法 150例甲状腺疾病患者采用解剖显露喉返神经方法行甲状腺腺叶切除或次全切除,解剖显露喉返神经270条.结果 术中发现喉不返神经6例,其中喉返神经损伤2条,术后恢复良好,顺利出院.结论 在甲状腺良恶性疾病手术中,熟悉喉返神经正常解剖及变异,常规解剖和显露可大大降低并发症,减少喉返神经的损伤.     

中间入路解剖喉返神经在甲状腺手术中的应用

目的探讨甲状腺手术中采用中间入路解剖喉返神经的价值。方法回顾性分析368例甲状腺手术中采用中间入路解剖喉返神经的患者资料,观察术后喉返神经损伤情况。结果暂时性喉返神经损伤2例(0.54%),无永久性损伤病例。结论中间入路解剖喉返神经,能减少喉返神经的损伤,是预防其损伤的有效方法。     

喉返神经喉外分支的临床意义(附13例报告)

目的：了解喉返神经喉外分支的解剖特点发病情况和术中喉返神经损伤的原因。方法：1991年至2001年共收治行甲状腺叶切除术的病人145例，术中常规解剖暴露喉返神经。结果：本组共发现喉返神经喉外分支13例，占9％。男4例，女9例，平均年龄46岁，右侧9例，左侧4例。喉返神经喉外分支分为2支者10例，占76．9％，3支者2例，1例为4个分支。喉外分支点距环甲关节入喉处的距离多在2cm以上，有的甚至低于甲状腺下动脉平面。结论：喉返神经有时常在喉外分为2或3个分支，为避免在甲状腺切除手术时损伤喉返神经，作者认为术中常规解剖暴露出喉返神经是避免其损伤的最好方法。     

甲状腺癌术中神经监测技术学习曲线的临床研究

目的 探讨甲状腺癌术中神经监测技术学习曲线的存在,降低喉返神经损伤并发症.方法 82例甲状腺癌患者行甲状腺癌根治术或联合根治术,解剖喉返神经147条,全部应用术中神经监测技术,“四步法”监测喉返神经功能,术中信号衰减幅度50％以上诊断喉返神经损伤,并判断损伤点和损伤原因.结果 喉返神经寻找时间为0.5～2 min,损伤率2.7％,喉返神经损伤病例均在术中诊断,损伤点均在喉返神经入喉点或临近入喉点的部位,损伤原因分别为牵拉、肿瘤粘连、热损伤和钳夹.按时间顺序分组以喉返神经的寻找时间和损伤例数生成甲状腺癌术中神经监测技术学习曲线,喉返神经寻找时间和损伤例数均有明显下降的趋势.结论 在甲状腺癌手术中应用术中神经监测技术存在技术学习曲线,有助于喉返神经的保护.     

术中神经监测技术在甲状腺手术中的应用与进展

喉返神经损伤是甲状腺手术较常见及最严重的并发症,尤其在复杂甲状腺手术及再次甲状腺手术中,因解剖层次不清、喉返神经解剖变异等所导致的喉返神经损伤机会加大。术中神经监测(IONM)是应用电生理技术监测术中神经功能完整性的一种技术,近年来研究显示,甲状腺手术中喉返神经IONM较常规暴露喉返神经能明显降低暂时性及永久性喉返神经损伤率。笔者就有关喉返神经IONM在甲状腺手术中的应用与进展进行综述。     

甲状腺手术中喉返神经变异的临床研究

目的 总结甲状腺手术中发现的喉返神经解剖变异的特点,并探讨各种变异类型的识别与保护要点.方法 回顾性分析2010年6月至2012年6月1548例常规显露喉返神经的甲状腺手术患者的临床资料,总结术中喉返神经的变异类型、变异率及解剖特点,分析神经的损伤情况.结果 1548例患者手术中显露喉返神经共2620根,其中全程解剖1886根,损伤11根(0.42％).全组2620根喉返神经中,发生条件变异共64根.1886根全程解剖的喉返神经中,存在自然变异共421根(22.3％),包括分支形态变异126根(6.68％),走行位置变异124根(6.57％),甲状腺下动脉处变异36根(1.91％),Berry韧带处变异112根(5.94％),环甲关节处变异17根(0.80％),非返型变异6根(0.32％).结论 甲状腺手术中所见喉返神经的变异复杂多样、变异率较高,其导致术中对神经的错误识别是造成神经损伤的重要潜在因素;全面掌握正常与各种变异的解剖特点是甲状腺手术中成功显露并保护喉返神经的关键.     

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 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.     

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.