自由描记肌电图监测腰椎手术中脊神经根功能的有效性分析

目的 :探讨单独应用自由描记肌电图监测腰椎手术中脊神经根功能的有效性。方法 :2014年10月~2015年10月共纳入246例腰椎病变在L2~S1节段之间且≤2个连续运动节段行单独自由描记肌电图监测的手术患者,男129例,女117例;年龄16~75岁,平均50.3±16.4岁。记录术中发生爆发性肌电活动、连续性肌电活动和自发性肌电活动的患者、相对应的手术操作、处理方法和转归。比较术前和术后神经功能状态,统计所有患者中真阳性、假阳性、真阴性和假阴性的病例,计算敏感性、特异性、阳性预测值和阴性预测值,分析自由描记肌电图监测的有效性。结果:术中监测时间80~140min,平均115.0±17.7min。所有患者中共有49例监测报警,爆发性肌电活动19例,连续性肌电活动27例,自发性肌电活动3例。其中,神经根牵拉过度28例,停止牵拉或减轻牵拉力度,肌电活动逐渐恢复正常;椎间融合器或植骨块植入挤压神经根8例,移除并改变植入角度避免挤压神经根,其中6例肌电活动逐渐恢复正常,2例转变为自发性肌电活动;椎弓根螺钉置入错位刺激神经根9例,移除并改变置钉轨道及角度,其中8例肌电活动逐渐恢复正常,1例右侧L5神经根支配肌肉仍有连续性肌电活动,术后右侧足背伸肌力减弱;4例患者探查未见刺激或损伤因素,肌电活动持续至手术结束,其中1例右侧S1神经根功能受损,术后右侧足底麻木;其余47例患者术后未出现神经功能受损。所有患者中197例未报警,术后1例左侧L5神经根功能受损,左侧胫前肌和背伸肌肌力0级。在阳性患者中,真阳性46例,其中2例术后神经功能受损;假阳性3例,阳性预测值为93.88%。在阴性患者中,真阴性196例,假阴性1例且术后神经功能受损,阴性预测值为99.49%。自由描记肌电图监测的敏感性为97.87%,特异性为98.49%。结论:应用自由描记肌电图监测L2~S1水平的手术可以减少神经根相关损伤,因其有较好的敏感性和特异性,可以对神经根功能的瞬间改变做出及时反馈,可作为腰椎手术中较为有效的神经监测方法。     

脊髓及神经根监测技术在脊柱外科手术中的应用

[目的]应用体感诱发电位（somatosensory evoked potential，SEP）行颈、胸椎手术脊髓监护及应用自发肌电图行腰椎手术神经根监护，对2种电生理检查的方法学、准确性及影响因素进行分析。[方法]颈、胸椎手术采用SEP监测，根据不同阶段SEP的变化与术后功能相结合，判断SEP的准确性。腰椎手术采用自发肌电图监测神经根功能，以判断神经根在术中是否受到牵拉、激惹及刺激。并观察手术中SEP及自发肌电图的影响因素，减少监测假阳性及假阴性的发生。[结果]颈、胸椎手术128例病人中，监护未达到预警标准116例，术后无神经症状加重表现。术中SEP变化达到预警标准8例，及时提醒手术医生，暂停手术操作，7例患者SEP波幅渐恢复，术后无神经症状加重。1例患者因SEP波幅降低时间超过10min未恢复，术后神经症状加重。非手术原因如麻醉、低血压及局部低温对SEP的影响均未达到预警标准。假阴性3例，假阳性1例。腰椎手术40例，12例术中出现肌电反应，及时提醒手术医生，避免过多的刺激及牵拉，术后均未出现神经根损伤症状。[结论]颈、胸椎手术，采用SEP监测，排除各种干扰因素，体感诱发电位可较准确地反应脊髓的生理或病理状况。腰椎手术采用自发性肌电图，在严格控制肌松剂使用下，可准确及时地反应神经根的功能，避免神经根的损伤。     

神经电生理监测在经皮内窥镜下腰椎间盘切除术中的应用

目的:探讨神经电生理监测在经皮内窥镜下腰椎间盘切除术中的应用。方法:回顾性分析2014年4月~2014年7月收治的37例单节段腰椎间盘突出症患者的临床资料,男16例,女21例;平均年龄48.4±17.5岁。其中单纯腰椎间盘突出症35例,腰椎间盘突出合并椎管狭窄症2例。所有患者均在局部麻醉下行微创经侧路经皮内窥镜下腰椎间盘摘除术(percutaneous endoscope lumbar discectomy,PELD)。术中运用自发性肌电图(spontaneous electromyography,SEMG)监测神经根功能,同时纪录患者的主观感受(疼痛),分析两者之间的关系。结果:在手术通道放置过程中,所有患者在出现腰部疼痛时,神经电生理无明显改变。2例患者无明显腿痛,电生理却出现明显的成串、波幅较大的肌电反应,调整通道后电生理改变趋于正常。35例患者有明显腿痛且神经电生理出现明显的成串、波幅较大的肌电反应,立即提醒术者,查找原因,调整手术通道后,患者腿痛消失,且电生理发生明显改变,异常肌电反应减轻,趋于正常。所有患者在腰椎间盘髓核摘除时,无明显疼痛且神经电生理无明显变化。在剥离、解压粘连神经根时,均出现明显连串的电位波形改变和明显的腿痛,停止手术操作后,腿痛消失,神经电生理恢复正常。在直视下刺激神经根时,患者出现明显的腿痛,同时神经电生理出现连串的电位。所有患者健侧的监测结果均无明显电生理改变。术后所有患者均无神经并发症。以神经电生理监测作为安全指标,其真阳性率为100%,而以疼痛作为安全指标,其真阳性率为94.6%;假阴性率为5.4%。结论:术中应用自发性肌电图监测可提供更为客观的安全指标,从而提高手术安全性。     

肌电图监测在极外侧入路椎间融合术联合经皮椎弓根螺钉内固定术中的应用

目的:探讨肌电图监测在极外侧入路椎间融合术(extreme lateral interbody fusion,XLIF)联合经皮椎弓根螺钉内固定术中应用的可行性和监测效果。方法:对46例行XLIF联合经皮椎弓根螺钉内固定术治疗的患者进行实时肌电图监测,其中男24例,女22例;年龄53.2±18.7岁。XLIF通道建立过程中采用自发肌电图监测神经根在术中是否受到牵拉、激惹等刺激,通过计算真阳性率和真阴性率得出监测的灵敏度和特异度。同时,利用诱发肌电图监测132枚椎弓根螺钉置入对神经电生理变化的影响。分析并推测手术中肌电监测的影响因素,尽量控制监测假阳性及假阴性的发生。为评价肌电监测的临床效果,记录肌电监测的阳性和阴性结果例数,并比较术前及术后1个月患者的JOA评分(Japanese Orthopaedic Association score)及Oswestry功能障碍指数(Oswestry disability index,ODI)评分。结果:46例患者共69个节段行椎间融合(L1/2 5例,L2/3 9例,L3/4 32例,L4/5 23例)。自发肌电监测有16例发现异常肌电波形,其中14例(真阳性)经调整手术操作后能恢复正常波形,2例(假阳性)经短暂观察后自行恢复至正常,14例患者中有3例术后出现神经根功能损伤症状。其余30例术中无异常肌电波形的患者中,有3例(假阴性)术后出现神经根功能损伤症状,27例(真阴性)术后无神经根功能损伤症状。通过上述数据计算得出术中自发肌电图监测灵敏度为82.35%,特异度为93.10%。后路经皮椎弓根螺钉固定术中采用诱发肌电监测132枚椎弓根螺钉置入(L1:8枚,L2:15枚,L3:27枚,L4:48枚,L5:34枚),其中118枚螺钉置入时肌电监测提示阴性,术后CT提示其中有5枚螺钉穿破椎弓根皮质。另外14枚螺钉攻丝后,刺激强度为10m A时出现肌电图反应,术后有13个椎弓根出现椎弓根内侧皮质骨折表现。患者术前JOA评分14.8±2.1分,术后为23.9±2.5分,较术前明显改善(P0.05)。术前ODI评分为38.3±3.1分,术后为13.6±2.9分,改善率为65.7%,较术前明显改善(P0.05)。结论:极外侧入路腰椎融合联合经皮椎弓根螺钉内固定术中应用肌电图监测具有较高的灵敏度和特异度,有一定的临床应用价值。     

应用肌电图进行术中腰神经根监护的初步报告

目的了解术中腰椎神经根监测的方法学、准确性及实用性，避免神经根的医源性损伤。方法术中使用美国Nicolet公司生产的Viking Select 8导肌电诱发电位仪监测腰椎手术39例：其中腰椎滑脱25例，腰椎管内肿瘤4例，腰椎管狭窄合并腰椎间盘突出6例，复发腰椎间盘突出4例。结果通过应用自发肌电图（EMG）进行术中监测，可以较为准确地判断腰椎神经根的功能，共有8例患者术中出现肌电反应，其中4例为腰椎滑脱，3例为腰椎间盘突出二次手术，1例为椎管内肿瘤。结论术中自发性EMG可准确及时地反应神经根的功能，避免神经根的损伤，保证腰椎手术的安全性。     

术中肌电图监测在脊髓栓系综合征手术中应用价值初探

目的探讨术中肌电图监测在脊髓栓系综合征（tethered cord syndrome,TCS）手术中的意义。方法 2010年1月～12月对19例TCS行术中肌电图监测,并使用激发肌电图辨别马尾神经和终丝。记录术中肌电图监测结果及术后新发神经功能障碍。结果术中记录电极在19例下肢骨骼肌和肛门括约肌均监测到爆发肌电和（或）持续性肌电活动,均告知术者予以处理。术后第1天4例出现新发神经功能障碍,术后第10天3例神经功能恢复正常,1例明显改善。19例均使用激发肌电图监测,在没有肌电爆发的部位行终丝切断。结论肌电图监测在TCS手术中可及时发现神经组织受到的牵拉、压迫等机械刺激,通知手术医生调整手术操作后,可能会减少术中医源性损伤的发生。用激发肌电图辨别终丝和马尾神经安全可靠。     

SEP联合实时EMG在腰骶神经根术中监护的价值探讨

目的探讨体感诱发电位(somatosensory evoked potential,SEP)联合术中实时肌电图(electrom yography,EMG)在腰骶神经根疾病术中的监护价值。方法自2013年3月至2016年5月利用SEP联合实时EMG对48例腰骶神经根疾病手术患者进行术中监护。结果 38例术中、术后获得满意SEP,EMG未出现持续肌电活动的,手术效果非常满意,6例术中SEP潜伏期延长小于5%~10%,波幅下降小于30%~50%,提醒手术医生谨慎操作,避免过度牵拉或长时间压迫止血,待SEP恢复后再进行手术。术后患者效果良好,4例SEP潜伏期延长大于10%,波幅下降大于50%,出现持续肌电活动,提醒手术医生暂停手术查找原因及时调整手术方式、术中给予相应处理等方法,待SEP恢复、持续肌电活动消失后再进行手术。2例手术效果良好,2例出现下肢疼痛,2周后症状减轻。结论 SEP联合术中实时EMG对腰骶神经根疾病术中的监护可全面及时反映脊髓及神经根的功能状态,减少手术并发症的发生,提高疗效及手术安全性。     

比目鱼肌H反射监测在全麻下经皮椎板间入路内窥镜下手术中的应用价值

目的 :观察全麻下经皮椎板间入路内窥镜下手术各操作步骤中使用H反射监测S1神经根功能的变化情况,明确该神经电生理参数在监测全麻下脊柱内窥镜手术中的应用价值。方法:14例单侧L5/S1椎间盘突出症(S1神经根损伤)患者被纳入本研究,男7例,女7例;年龄25~53岁;身高160~177cm。均行全麻下经皮椎板间入路内窥镜下单纯髓核摘除术。术前、术中各操作步骤(通道置入、神经根暴露、突出髓核摘除及内窥镜系统退出)及术后分别记录双侧下肢比目鱼肌H反射,测量并对比潜伏期及波幅(基线-负向波峰)等参数,并对结果进行统计学分析。结果:以术前完成全麻插管后、在手术体位所测得的H反射参数作为术中H反射的基线值。术中,患侧H反射波幅自神经根暴露(通道触碰或挤压神经根)阶段开始便出现明显下降(P0.05),在剥离推移神经根时H反射波幅下降幅度最为明显[平均下降(43.9±20.5)%,P0.05],而后虽有回升,但较基线值仍存在统计学差异(P0.05);手术结束时,所有患者患侧H反射都得以保留,但波幅仍较基线值下降约(15.1±9.0)%(P0.05)。术后第2日,所有患者VAS评分(Visual analogue scale)明显好转(术前vs.术后:6.4±1.3 vs.0.6±0.6,P0.05);12例患者复测患侧H反射,各项参数相较于术前无明显差异(P0.05)。2例患者术中出现H反射波幅下降超过85%的情况,在停止操作、放松牵拉神经根后数十秒,H反射都得以部分恢复,术后未出现明显的感觉或运动障碍。结论:比目鱼肌H反射波幅能有效反映经皮椎板间入路内窥镜手术各操作步骤中S1神经根的电生理传导功能,术中应用H反射监测技术可为全麻下脊柱内窥镜手术提供额外的、可靠的辅助监护手段。     

经椎板间入路和经椎间孔入路脊柱内镜下治疗L5-S1椎间盘突出症的临床疗效比较

目的回顾性分析经椎板间入路(PEID)和经椎间孔入路(PETD)行脊柱内镜手术治疗L_5-S_1椎间盘突出症的临床疗效。方法选取2017年1月-2018年3月行脊柱内镜下髓核摘除手术治疗的114例L_5-S_1椎间盘突出症患者(其中PEID手术56例,PETD手术58例),对比两种手术疗效。结果两组患者均顺利完成手术,PEID组手术时间和透视次数均显著少于PETD组,差异有统计学意义(P0.05)。两组患者末次随访的VAS评分和ODI评分均较术前明显改善(P0.05),但组间差异无统计学意义(P0.05)。根据改良MacNab标准,PEID组优良率为85.7%,PETD组优良率为86.2%,两组差异无统计学意义(P0.05)。PEID组出现3例硬脊膜撕裂(无脑脊液漏),2例神经根损伤(均经保守治疗后好转),6例短暂性下肢症状加重,2例术后复发; PETD组未出现硬脊膜撕裂,2例神经根损伤(1例经保守治疗后恢复,1例永久性损伤),3例出现短暂的下肢症状加重,3例术后复发。结论 PEID与PETD均可以用于L_5-S_1椎间盘突出症的治疗。二者相互补充,其中PEID手术时间短,透视次数少,但硬脊膜和神经根损伤风险较PETD高。临床应用中应根据解剖特点,并结合操作者的熟练程度选择手术合适的入路。     

自由描记肌电图应用于腰椎手术中神经根监测的临床价值

目的探讨腰椎手术中应用自由描记肌电图(free-run electromyography,F-EMG)进行神经根监测的临床价值。方法自2015-11-2016-11,在132例腰椎手术中应用F-EMG进行实时监测,包括后路病灶清除、融合内固定术9例,后路减压融合内固定术106例,后路椎弓根钉内固定手术17例。对患者术中F-EMG表现情况及术后转归进行统计分析。结果 (1)132例中,共发生F-EMG报警28例,其中连续性肌电活动17例,爆发性肌电活动9例,自发性肌电活动2例;探明术中F-EMG异常原因有25例,均予以调整手术操作;未探明原因3例,其中2例为假阳性。未发生F-EMG报警104例,其中1例术后发生神经损伤(为假阴性)。(2)经证实,F-EMG术中监测的真阳性26例,假阳性2例;真阴性103例,假阴性1例。其敏感度为96.3%,特异度为98.1%,阳性预测值为92.9%,阴性预测值为99.0%。结论腰椎手术中予以F-EMG监测,具有较高的敏感度和特异度,起到可靠的预警作用,降低了神经根损伤的发生率,可作为一项较佳的腰椎手术配备方案予以考虑。     

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.     

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.