骶椎神经源性肿瘤的外科治疗

目的:观察Ⅰ期肿瘤切除手术治疗骶椎神经源性肿瘤的疗效及并发症,探讨手术相关的解剖学原理。方法:对2001年1月至2018年1月手术治疗的26例骶椎神经源性肿瘤患者进行回顾性分析,男16例,女10例;年龄21~69(39.3±10.9)岁;病程3~56(17.9±10.1)个月;骶前肿块直径3.3~19.6(8.7±4.1) cm;骶前肿块上缘高于和不高于L₅S₁间隙水平者分别为6和20例。手术均先取后入路,必要时附加前入路,Ⅰ期切除肿瘤,部分患者行腰椎-骨盆内固定重建,术中视情况决定是否保留载瘤神经根。记录患者的手术时间、术中出血量、疼痛缓解程度及并发症情况。术后随访评估腰骶椎稳定性和神经功能,并检查有无局部复发和远处转移。结果:26例均Ⅰ期完整切除肿瘤,手术时间(160.4±35.3) min,术中出血量(1 092.3±568.8) ml。单纯后入路21例,前后联合入路5例。前后联合入路者骶前肿块直径11.3~19.6(15.1±3.2) cm,单纯后入路者为3.3~10.9(7.2±2.4) cm。骶前肿块上缘高于L₅S₁间隙的6例患者中5例采取了前后联合入路,不超过L₅S₁间隙的20例均为单纯后入路。所有病例获得随访,时间6~82(45.4±18.2)个月。术后腰骶痛、下肢根性痛均明显缓解,感觉、肌力和二便功能也有不同程度改善。术后切口浅表感染1例,脑脊液漏2例。病理证实神经鞘瘤17例,神经纤维瘤7例,恶性神经鞘瘤2例。2例良性神经源性肿瘤局部复发,1例恶性神经鞘瘤术后20个月时死于肺转移。17例高位骶骨神经源性肿瘤有4例未行内固定重建,其中2例术后脊柱失稳。7例切除载瘤神经根,其中1例同时切除S₂和S₃神经根的患者术后出现膀胱和直肠功能异常,且未能完全恢复,另6例神经功能无明显损害或恢复良好。结论:后入路能直接显露病灶,处理神经根和血管也方便,手术时间、术中出血量、症状缓解程度、并发症率和复发转移率均能控制在适当水平,是安全有效的手术入路;但当骶前肿块上缘高于L₅S₁水平或骶前肿块直径达到10 cm以上时,应考虑附加前方入路。脊柱和骨盆之间应力较高,高位骶椎神经源性肿瘤切除术中应使用内固定重建脊柱-骨盆的力学连续性。载瘤神经根多已丧失功能,切除单根载瘤神经根不易引起严重神经功能障碍,而邻近神经根具有代偿功能,术中应尽量保留。     

胸腰椎管内神经鞘膜瘤影像学表现和手术治疗的临床观察

目的:探讨胸腰段神经鞘膜瘤的影像学特点和手术治疗效果。方法:自2005年6月至2012年12月,手术治疗胸腰椎管内神经鞘膜瘤17例,其中男11 例,女6 例;年龄46～67 岁,平均53 岁;病程3～5 年,平均3.3 年。胸段患者表现为胸背痛,逐渐出现下肢麻木无力或行走不稳;腰段表现为腰背痛,下肢放射痛或感觉麻木,以及间歇性跛行。术前VAS评分 (疼痛视觉模拟标尺法) 5～8分,平均6.12分。11例患者神经功能受损,Frankel C级4例,D级5例,E级2例。CT和MRI检查提示病变部位:胸段3例,胸腰段5例,腰段3例,腰骶段6例;硬膜外5例,髓外硬膜下12例。6例单纯行椎管减压、肿瘤切除术,11例行椎管减压、肿瘤切除及后路内固定植骨融合术。结果:术中未发生大血管或脊髓损伤,术后伤口均正常愈合。17例患者术后均获随访,时间12～60 个月,平均32个月。胸背痛、腰背疼痛和下肢放射痛等显着改善,下肢麻木感明显缓解。末次随访VAS评分 0～3分,平均1.5分。神经功能受损患者末次随访Frankel分级:D级5例,E级6例。结论:MRI 是胸腰段神经鞘膜瘤有效的辅助诊断方法,影像学表现决定具体手术方法,手术目的是椎管有效减压、肿瘤彻底切除和脊柱稳定性的重建。     

肾上腺节细胞神经瘤的诊治(附7例报告)

目的探讨肾上腺节细胞神经瘤的诊治。方法依据B超、CT及MRI等影像学检查结果对7例肾上腺节细胞神经瘤患者进行诊断,开放手术或腹腔镜手术切除肿瘤。结果手术顺利,仅1例术中血压波动。术后病理报告肾上腺节细胞神经瘤。术后血压正常,恢复良好,随访6个月～5年,未见复发。结论肾上腺节细胞神经瘤多无特异性临床表现,诊断主要依靠影像学检查,手术切除预后良好。     

脊柱肿瘤的全脊椎切除术及脊柱稳定性重建

目的探讨对脊柱肿瘤行全脊椎切除术的可行性与临床价值,以及重建脊柱稳定性的可靠方法。方法对27例椎体和附件结构均遭破坏的脊柱肿瘤采用全脊椎切除及内固定重建技术进行治疗,其中包括上颈椎至下腰椎的良、恶性及转移性肿瘤,手术切除1～3节脊椎。结果23例获完整随访,随访时间7～96个月(平均25个月)。1例L5恶性神经纤维瘤及1例C6,7巨细胞瘤于术后10个月及12个月复发,患者放弃治疗;1例C2～4脊索瘤术后1年复发,再次手术效果良好;其余20例未见复发。25例术前伴神经功能损害者,术后有23例获显著改善。结论全脊椎切除术为治疗全脊椎受累脊柱肿瘤的有效方法;切除1～3节脊椎的脊柱可由相应内固定系统进行可靠的稳定性重建。     

硬膜外哑铃形神经鞘瘤的手术治疗

目的探讨硬膜外哑铃形神经鞘瘤的显微外科手术治疗效果。方法回顾性分析2010年8月~2016年12月经显微手术切除的52例硬膜外哑铃形神经鞘瘤的临床资料。根据肿瘤向椎管内外生长的特点指导手术入路的选择,后方选择后正中或旁正中入路,前方在颈部选择侧前方入路,胸部选择胸腔镜辅助,腰部选择腹膜后腹腔镜辅助。于显微镜下用神经外科显微器械行硬膜外神经鞘瘤切除术。后正中全椎板入路且无小关节破坏时行椎板成形术,小关节被破坏时行一期内固定。均严密缝合肌肉及筋膜层。结果采取后正中入路42例(全椎板入路20例,半椎板入路22例),旁正中入路4例,前后路联合手术入路6例。全切除50例,2例因肿瘤包绕同侧椎动脉行次全切除。其中36例行一期脊柱内固定术或椎板成形术。手术时间60~120 min,平均81 min;术后引流1~2 d;术后住院时间7~12 d,平均9.5 d。术后病理均为神经鞘瘤。5例伤口深方积液,术后无感染、脑脊液漏、瘫痪及死亡。术后随访6~60个月,(26.8±6.2)月。33例疼痛患者疼痛均消失;42例肌力下降患者肌力较术前提高Ⅰ~Ⅱ级;44例感觉异常者中,感觉恢复正常33例,感觉减退区域缩小5例,无明显变化4例,新发或感觉障碍区域扩大2例。按Mc Cormick分级,均为Ⅰ级。结论硬膜外哑铃形神经鞘瘤向椎旁生长大多在4 cm以内,可通过单纯后方入路切除;当向椎旁生长4 cm时需联合前方入路切除。通过适当的入路显微手术,可Ⅰ期全切肿瘤。     

术中肢体被动运动在脊柱外科俯卧位手术臂丛神经保护中的护理疗效

目的 探讨术中肢体被动运动在俯卧位脊柱手术病人术中体位性臂丛神经损伤的干预效果和护理要点。方法 选取2018年1月至12月在我院骨科实施俯卧位脊柱手术病人377例,术中采用双上肢尺神经体感诱发电位（somatosensory evoked potentials, SEP）监测,在病人上肢肌力电位下降时,给予肢体肌肉按摩、关节适度被动运动干预。观察术前、干预前和干预后病人上肢肌力电位的阈值和潜伏期变化情况。结果 术中11例出现上肢肌力电位下降,其中7例（63.6%）行肢体被动运动干预40~70 min后上肢SEP恢复正常,恢复时间为（47.31±15.57） min;4例在3 h内恢复正常。手术前、干预前和干预后的潜伏期比较,差异无统计学意义（P=0.236）。手术前、干预前和干预后病人上肢肌力电位的阈值比较,差异有统计学意义（F=16.218,P＜0.001）,且干预后上肢尺神经阈值明显高于干预前,差异有统计学意义（P＜0.05）。11例病人术后均未出现上肢功能障碍及其他臂丛神经损伤症状。结论 基于神经电生理监测的术中肢体被动运动,有助于改善俯卧位脊柱手术病人术中上肢肌力下降,减少术中体位并发症,促进病人术后恢复。     

腹膜后节细胞神经瘤的临床病理特征及手术疗效分析

目的探讨腹膜后节细胞神经瘤的临床诊治方法及疗效。方法回顾性分析2015年4月至2022年5月北京大学国际医院收治的32例腹膜后节细胞神经瘤的临床资料, 探讨其临床特点、手术疗效及预后。结果 32例腹膜后节细胞神经瘤中无明显临床症状17例, 腹胀、腹痛7例, 腰背部疼痛6例, 腹部包块2例。18例位于肾上腺及肾区附近, 11例位于肾下方脊柱两侧, 3例位于盆腔。28例为单发肿瘤, 4例为多发肿瘤, 12例包绕大血管。手术R0或R1切除共27例, R2切除5例, 联合脏器切除6例, 采用分块切除8例。肿瘤平均最大直径(13.2±4.9)cm, 术中中位出血量为500 ml(50～6 000 ml), 术后发生并发症6例。包绕血管的肿瘤组与未包绕血管的肿瘤组在年龄、出血量、R2切除率、分块切除比例方面差异均有统计学意义(t=2.44, P=0.021;Z=2.37, P=0.018;χ2=4.57, P=0.033;χ2=11.38, P=0.001)。R0或R1切除的患者无复发。结论腹膜后节细胞神经瘤完整切除的患者预后良好, 包绕血管的肿瘤手术难度大, 导致不能完整切除。     

颈椎节细胞神经瘤的临床特点与手术治疗

目的:总结颈椎节细胞神经瘤的临床特点,探讨其手术治疗效果。方法:2001年6月～2007年7月我院手术治疗颈椎节细胞神经瘤患者10例,男5例,女5例,年龄28～65岁,平均45.1岁。6例以根性疼痛为主要表现,4例以肿瘤压迫平面以下肌力下降为主要表现,3例患者有与肿瘤所在水平相关的感觉障碍平面。MRI检查显示肿瘤在T1WI呈低信号、T2WI呈高信号,增强后有强化;在轴位像上肿瘤位于髓外-硬膜内外者3例,其中2例沿椎间孔呈哑铃形生长,7例肿瘤位于硬脊膜外-椎间孔内外呈哑铃形;C1～C2水平者4例,C3～C41例,C4～C51例,C5～C63例,C4～C61例。2例肿瘤主体位于髓外-硬膜下者采用常规双侧椎板切除显露,8例肿瘤主体位于椎间孔者采用患侧半椎板-小关节突切除显露,于显微镜下行肿瘤分离切除。2例哑铃形肿瘤椎管外部分较大,附加后外侧入路切除椎旁部分。结果:肿瘤全切除9例,次全切除1例。术后病理检查可见成熟或未成熟的肿瘤性节细胞散在或成束穿插于肿瘤性雪旺氏细胞间质中,肿瘤中可见正常的神经纤维呈束状排列。术后发生脑脊液漏2例,经对症处理后治愈。术前6例神经根痛患者,术后4例症状缓解或消失,2例无变化。术前4例上、下肢运动障碍者,术后3例改善,1例无变化。随访2.1～7.2年,平均4.1年,末次随访时脊髓功能状态按McCormick分级标准评价,好转8例,不变2例。随访期间1例次全切除患者术后2年肿瘤原位硬膜下复发,再次手术切除,另9例无复发。结论:颈椎节细胞神经瘤临床上以根性疼痛及感觉运动障碍为主要表现,肿瘤形态大多数为骑跨椎间孔呈哑铃形生长,肿瘤主体多位于硬膜外。手术全切除后预后良好。     

肢体恶性骨肿瘤及骨转移癌保肢治疗

目的:探讨肢体恶性骨肿瘤及转移癌行瘤段切除假体重建的方法及意义。方法:本组共62例,男38例,女24例;年龄10⁷2岁,平均28.4岁。原发肢体恶性骨肿瘤41例,其中骨肉瘤19例,骨巨细胞瘤9例,恶性纤维组织细胞瘤8例,浆细胞瘤3例,尤文氏瘤1例,骨血管内皮瘤1例。骨转移癌21例,原发病灶分别为:肺癌9例,胃癌3例,肾癌2例,乳腺癌2例,甲状腺癌1例,颌下腺癌1例,原发灶不明者3例。对62例肢体恶性骨肿瘤及转移癌应用肿瘤段切除并修复重建治疗。方法有:①瘤段切除人工假体置换术;②瘤段切除自体腓骨移植术;③瘤段切除髓内针骨水泥重建术。结果:术后随访5⁴2个月,平均14.2个月,41例恶性骨肿瘤中,术后无瘤生存21例,死亡4例,7例发生肺转移,3例发生其他部位转移,6例局部复发后截肢。37例生存患者患肢功能按Enneking骨肿瘤外科治疗后功能评定标准,优良率81.1%。21例骨转移瘤患者中,术后存活3个月以上者19例（占90.4%）;术后疼痛消失15例（占71.4%）,其余均有疼痛减轻;日常生活工作恢复者11例（占52.3%）。结论:对可施行广泛切除的肢体恶性骨肿瘤患者采用不同方法修复重建,行保肢治疗,可在治疗肿瘤的前提下尽量保留肢体功能,对肢体骨转移癌行合适的保肢手术对提高骨转移癌患者的生存质量有积极意义。     

胫骨造釉细胞瘤手术方法选择

目的:探讨胫骨造釉细胞瘤手术方法选择的应用价值。方法:胫骨造釉细胞瘤患者5例,男4例,女1例;年龄14⁶1岁,平均37.8岁。5例行手术治疗,先后多次复发。早期行病灶刮除、自体骨、异体骨或人工骨植骨术,全部复发。复发后又先后行瘤段切除、自体游离腓骨移植术,瘤段切除、异体骨移植术。最终4例行截肢术。结果:术后随访10个月³年,平均12.4个月。病灶刮除植骨术后复发5例,3例再行瘤段切除、自体游离腓骨髂骨移植术,其中2例复发;2例再行瘤段切除、异体骨移植术,均复发。复发的4例均采取截肢治疗。出现肺转移1例,行肺转移灶切除术;出现骨转移1例,行髋关节离断术,随访末期死亡0例。结论:虽然胫骨造釉细胞瘤有很高的复发率,但经过积极正确的手术方法治疗,预后尚好。     

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.