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。     

自由肌电图监测在脊柱内镜下经维板间入路腰椎间盘切除术中的初步应用

目的 :探讨自由肌电图监测在全麻脊柱内镜下经椎板间入路腰椎间盘切除术(percutaneous endoscopic interlaminar discectomy,PEID)中应用的可行性和效果。方法:回顾性分析2016年3月~2017年6月共86例接受全麻下PEID手术的腰椎间盘突出症患者,男62例,女24例;年龄平均41.2±8.1岁(23~64岁)。所有患者术中持续应用自由肌电图进行神经根功能监测,观察肌电图波形、峰值和运动单元数量。如果出现任何形式的肌电反应,均提示神经根受到一定激惹,而连续爆发性肌电反应则提示神经根受到持续的牵拉或者压迫。若手术结束时仍有明显异常的肌电反应存在,则预测为神经根损伤,并与术后患者症状比较。结果:术中在触碰、推挤及牵拉神经根时,相应的自由肌电图监测均出现肌电反应,记录阳性率为100%。共有79例患者术后症状明显缓解,6例患者术后出现下肢神经灼性疼痛症状,1例患者术后出现下肢肌力下降和麻木加重。以上患者中有1例术中出现明显肌电反应,手术结束时为正常,术后出现明显下肢神经灼性疼痛,假阴性预测率1.16%;有2例手术结束时肌电图监测仍有明显异常患者术后症状明显缓解,未有明显神经痛,假阳性预测率2.32%。结论:自由肌电图监测能比较准确地反映全麻下PEID手术中神经根干扰情况,从而起到减少神经损伤的目的。     

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。     

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。     

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。     

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。     

运动诱发电位和肌电图联合监测在微创经椎间孔腰椎椎间融合术中的有效性及安全性

目的评估运动诱发电位(MEP)和肌电图(EMG)联合监测在微创经椎间孔腰椎椎间融合术(MIS-TLIF)中的有效性及安全性。方法回顾性分析2016年1月—2016年6月行MIS-TLIF治疗的64例腰椎椎管狭窄症患者的临床资料,于术中采用MEP和EMG联合监测,并使用监测安全预警,保证MIS-TLIF的安全性。结果本组患者中44例术中MEP和EMG均未发生显著性改变,术后恢复良好,未出现神经功能障碍。20例术中发生MEP和/或EMG显著性改变,其中2例由非手术因素造成信号变化,术后未出现神经功能障碍,列入真阴性;18例确认信号改变与高危手术操作相关。后者有3例术后出现神经功能障碍,其中1例右侧小腿麻木加重;1例右侧足背伸肌肌力减弱,末次随访时肌力恢复至5级;1例术后腰痛及双下肢麻木、疼痛改善不明显,术后1年随访时双下肢麻木、疼痛同术前,考虑为神经功能障碍。MEP和EMG联合监测的敏感性为100.0%,特异性为75.4%,阳性预计值为16.7%,假阳性率为24.6%,阴性预计值为100.0%,假阴性率为0,与单独应用MEP或EMG监测相比提高了敏感性。结论 MEP和EMG联合监测比单一形式的监测更为敏感,术者可获得连续的反馈信息,使多数假阳性信号在术中得到注意或纠正,避免转变为真阳性,提高了脊柱微创手术的有效性和安全性。     

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。     

经颅电刺激运动诱发电位在胸椎管狭窄症手术中的应用价值

背景:经颅电刺激运动诱发电位(MEP)因其可即时反应术中脊髓功能状态已广泛应用于脊柱手术中,尤以脊柱矫形、颈椎手术多见,而有关胸椎管狭窄症手术中应用MEP的报道相对较少。目的目的:分析胸椎管狭窄症手术中MEP神经功能监测的应用价值和监测效能。方法方法:回顾性分析2012年10月至2016年7月我院进行的47例58次胸椎管减压手术。手术方式主要为后路扩大全椎板切除术、经椎间孔胸椎椎间融合术(TTIF),术中应用MEP进行神经功能监测。监测采用经颅电刺激C3、C4位点,记录外周肌源性MEP。报警阳性诊断标准:排除系统性因素及麻醉相关因素外,与高危操作(减压、cage置入、椎弓根螺钉置入等)相关的波形快速丢失超过80%。结果结果:58次胸椎管减压手术中成功获取可靠术前波形并具有监测价值者47次,检出率为81.0%。真阳性结果3例,其中1例经及时处理后术后无神经功能障碍;2例出现暂时性神经功能障碍,经甲泼尼龙冲击治疗后逐渐恢复。假阳性结果 1例。未出现假阴性结果。MEP监测的敏感度和特异度分别为100%和97.7%,阳性预测值和阴性预测值分别为75%和100%。2例患者术后出现迟发性脊髓损伤,考虑脊髓再灌注损伤,经甲泼尼龙冲击治疗后神经功能逐渐恢复。结论结论:胸椎管狭窄症手术难度大,脊髓损伤风险高,术中应用MEP监测能为手术提供客观的安全评估指标,但术后仍需警惕迟发性脊髓损伤的发生。     

重度脊柱畸形翻修截骨术中神经监测变化的危险因素

[目的]评估联合体感诱发电位(somatosensory evoked potential,SSEP)和经颅运动诱发电位(transcranial motor evoked potential,TcMEP)监测在重度脊柱畸形翻修截骨矫形手术中的应用价值,探讨术中出现神经监测变化的危险因素。[方法]回顾性分析2015年1月~2017年1月于本科全麻下进行重度脊柱畸形翻修截骨矫形手术54例患者,男19例,女35例。术中均应用SSEP和TcMEP联合监测。统计比较单模式SSEP、单模式TcMEP及双模式联合监测的阳性预测值和阴性预测值、敏感性及特异性。分析术中出现真阳性电生理监测变化的原因和危险因素,并提出相应的管理措施。[结果]联合SSEP及TcMEP监测成功率、阳性预测值、阴性预测值、敏感性及特异性均为最高。54例患者中共有14例(25.93%)出现阳性电生理监测变化。经术中干预后,随访时最终2例(3.70%)未恢复至术前神经功能状态。术前合并胸椎管狭窄、主弯Cobb角130°为出现真阳性电生理变化的危险因素。[结论]在重度脊柱畸形翻修截骨矫形手术中,联合SSEP及TcMEP监测能有效地检测早期脊髓损伤,有更好地进行预警的价值。积极进行干预能扭转电生理变化并可以避免严重脊髓损伤并发症发生。翻修术中截骨矫形过程出现电生理变化概率较高。术前合并胸椎管狭窄以及主弯Cobb角130°的患者更易导致真阳性监测变化发生。     

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.     

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.