乳腺癌改良根治术麻醉的优化策略：混合药物单次胸椎旁神经阻滞联合全麻

目的评价混合药物单次胸椎旁神经阻滞(TPVB)联合全麻用于乳腺癌改良根治术麻醉的优化效应。方法择期全麻下行初次乳腺癌改良根治术病人60例,年龄20～60岁,BMI<30 kg/m2,ASA分级Ⅰ或Ⅱ级。采用随机数字表法分为2组(n=30):混合药物单次TPVB组(PV-SI组)麻醉诱导后0.25%罗哌卡因25 ml、地塞米松3 mg、丁丙诺啡120 μg和肾上腺素2.5 μg/ml单次TPVB联合全麻;持续输注TPVB组(PV-CI组)麻醉诱导后0.25%罗哌卡因25 ml和肾上腺素2.5 μg/ml混合液单次注射后持续输注0.125%罗哌卡因8 ml/h至术后48 h。手术结束时连接病人自控静脉镇痛泵,单次按压吗啡剂量2 mg,锁定时间10 min,无负荷剂量及背景输注。记录术后镇痛持续时间、术后48 h内吗啡总消耗量、恶心呕吐发生情况、病人推荐及满意情况。结果与PV-CI组比较,PV-SI组术后镇痛持续时间、术后48 h内吗啡总消耗量、恶心呕吐发生率、病人推荐率及满意率差异无统计学意义(P>0.05)。结论混合药物单次TPVB联合全麻可作为有助于改善乳腺癌改良根治术病人...     

复方倍他米松复合罗哌卡因胸椎旁阻滞用于胸腔镜术后镇痛的效果

目的 探讨超声引导下复方倍他米松复合罗哌卡因胸椎旁阻滞用于胸腔镜术后镇痛的效果。方法 选择行择期胸腔镜手术患者60例,男41例,女19例,年龄18～60岁,BMI 18～25 kg/m²,ASAⅠ或Ⅱ级。采用随机数字表法将患者分为两组：复方倍他米松复合罗哌卡因组(B组)和罗哌卡因组(R组),每组30例。两组在麻醉诱导前行超声引导下胸椎旁阻滞,B组注射药物为加入复方倍他米松0.5 ml的0.4%罗哌卡因25 ml, R组注射药物为0.4%罗哌卡因25 ml。两组均采用标准化的支气管插管静脉全麻方案,术后行PCA。记录阻滞起效时间、镇痛持续时间、PCA首次按压时间,术中舒芬太尼、瑞芬太尼、丙泊酚用量,术后2、4、8、12、24、48 h静息和活动时(咳嗽)VAS疼痛评分,术后48 h PCA总按压次数和舒芬太尼补救镇痛例数,术后48 h内呼吸抑制、恶心呕吐、穿刺部位感染、尿潴留等不良反应发生情况。结果 与R组比较,B组阻滞起效时间明显缩短(P<0.05),镇痛持续时间、PCA首次按压时间明显延长(P<0.05)。两组术中舒芬太尼、瑞芬太尼、丙泊酚用量差异均...     

罗哌卡因复合右美托咪定或地塞米松竖脊肌平面阻滞用于腰椎后路植骨融合内固定术的效果

目的比较罗哌卡因复合右美托咪定或地塞米松竖脊肌平面阻滞(ESPB)在腰椎后路植骨融合内固定术中的临床效果。方法选择2019年10月至2020年10月择期行腰椎后路植骨融合内固定术患者75例,男42例,女33例,年龄35～65岁,BMI 18～35 kg/m~2,ASAⅠ或Ⅱ级。采用随机数字表法将患者分为三组:罗哌卡因复合右美托咪定组(RX组)、罗哌卡因复合地塞米松组(RS组)和单纯罗哌卡因组(R组)。三组麻醉诱导前均行ESPB,RX组两侧分别注射0.375%罗哌卡因+右美托咪定0.5μg/kg混合液20 ml, RS组两侧分别注射0.375%罗哌卡因+地塞米松5 mg混合液20 ml, R组两侧分别注射0.375%罗哌卡因20 ml。记录术中瑞芬太尼和舒芬太尼用量。记录术后4、8、12、24、48 h静息和翻身时数字评价量表(NRS)评分。记录感觉阻滞持续时间、镇痛泵首次按压时间和补救镇痛例数。记录术后24 h内镇痛满意度及术后当晚睡眠质量。记录术后下肢运动阻滞、穿刺部位血肿、恶心呕吐、低血压、心动过缓、手术部位感染和切口延迟愈合等发生情况。结果与R组比较,术后12、24 h RX组和RS组静息和翻身时NRS评分明显降低(P0.05),感觉阻滞时间和镇痛泵首次按压时间明显延迟(P0.05),补救镇痛率明显降低(P0.05),24 h内镇痛效果及术后当晚睡眠质量满意度评分明显升高(P0.05)。三组穿刺部位血肿和恶心呕吐发生率差异无统计学意义。三组均无一例发生术后下肢运动阻滞、低血压、心动过缓、手术部位感染和切口延迟愈合。结论右美托咪定或地塞米松复合罗哌卡因用于后路腰椎手术竖脊肌阻滞,可以延长感觉阻滞时间,有效控制术后急性疼痛,临床效果相似。     

右美托咪定复合罗哌卡因胸椎旁神经阻滞在单侧开胸手术后的镇痛效果

目的观察右美托咪定复合罗哌卡因胸椎旁神经阻滞(thoracic paravertebral nerve block,TPVB)应用于单侧开胸手术的安全性及术后镇痛效果。方法选择40例单侧开胸食管癌手术患者,随机分为两组,每组20例。全麻诱导前行开胸肋间TPVB,R组注入0.5%罗哌卡因15ml,D组注入含有右美托咪定0.75μg/kg的0.5%罗哌卡因15ml,30min后开始全麻诱导。术后行椎旁自控镇痛。记录注药前(T0)、注药后5、10、15、20、30min(T1~T5)、气管插管前(T6)、气管插管后(T7)的MAP、HR、BIS以及椎旁阻滞起效时间、阻滞平面宽度及并发症等。记录术后24h追加吗啡镇痛次数、咪达唑仑镇静次数、呕心呕吐及患者镇痛满意度等。结果两组TPVB范围及起效时间差异无统计学意义。与T0时和R组比较,T4、T5时D组HR明显减慢,MAP、BIS明显降低(P0.05)。与T6时比较,T7时R组HR明显增快、MAP、BIS明显升高(P0.05)。术后镇痛期间,与R组比较,D组追加吗啡和咪达唑仑次数、呕心呕吐发生率明显减少(P0.05)。结论右美托咪定0.75μg/kg复合0.5%罗哌卡因15 ml诱导前行TPVB,术后右美托咪定0.1μg·kg-1·h-1及0.5%罗哌卡因2ml/h持续TPVB,可安全用于单侧开胸手术和术后镇痛,较单用0.5%罗哌卡因TPVB具有明显的优势。     

超声引导下罗哌卡因复合地塞米松腰方肌阻滞对全髋关节置换术患者术后镇痛的影响

目的 研究超声引导下腰方肌阻滞中罗哌卡因复合地塞米松对全髋关节置换术后镇痛的疗效。
方法 选择2019年12月至2020年12月行全髋关节置换术的患者90例,男40例,女50例,年龄65～78岁,ASA Ⅰ或Ⅱ级。采用随机分组的方法分成罗哌卡因复合地塞米松组（D组）,罗哌卡因组（Y组）和单纯静脉自控镇痛（PCIA）组（R组）,每组30例。D组术后以罗哌卡因100 mg复合地塞米松0.1 mg/kg为药液行腰方肌阻滞同时联合PCIA作为术后镇痛,Y组术后以单纯罗哌卡因100 mg为药液行腰方肌阻滞并联合PCIA为术后镇痛,R组则采用单纯PCIA作为对照。记录三组术后4、6、12、24和48 h静息和活动时VAS疼痛评分以及术后48 h内镇痛泵按压次数及曲马多补救例数。同时记录术后48 h内恶心呕吐、呼吸抑制和术后谵妄等不良反应发生情况,记录患者对术后镇痛的满意度。
结果 术后4、6、12、24和48 h D组和Y组静息和活动时VAS疼痛评分明显低于R组（P<0.05）,术后12、24 h D组的静息和活动时VAS疼痛评分明显低于Y组（P<0.05）。术后48 h D组和Y组内镇痛泵按压次数和曲马多补救例数明显少于R组（P<0.05）,且D组明显少于Y组（P<0.05）。术后48 h内D组和Y组恶心呕吐发生率明显低于R组（P<0.05）,且D组明显低于Y组（P<0.05）。三组均未发生呼吸抑制和术后谵妄。D组术后镇痛的满意度评分明显高于Y组和R组（P<0.05）。
结论 超声引导下罗哌卡因复合地塞米松腰方肌阻滞对全髋关节置换术患者术后镇痛的效果好,不良反应少,提高患者对术后镇痛的满意度。     

右美托咪定混合罗哌卡因胸椎旁神经阻滞在全麻胸腔镜肺癌根治术后镇痛效果研究

目的探讨右美托咪定混合罗哌卡因胸椎旁神经阻滞(TPVB)在全麻胸腔镜肺癌根治术后的镇痛效果。方法将72例接受全麻胸腔镜肺癌根治术的患者随机分为2组,各36例。2组均行TPVB,观察组注入0.5μg/kg右美托咪定+0.375%罗哌卡因混合液20 mL,对照组注入0.375%罗哌卡因20 mL。比较2组术后1 h、6 h、12 h、2 4 h静息和运动时VAS评分。采用QoR-40量表对患者术前1天、术后第3天,以及术后1个月的身体舒适度、情绪状态、自理能力、心理支持、疼痛5项进行评估对比;对比术后24 h内PCIA舒芬太尼的使用量、PCIA按压次数、镇痛补救率;记录患者术后苏醒时间、气管导管拔除时间、恢复室停留时间、术后住院时间以及麻醉相关并发症等发生情况。结果与对照组比较,观察组静息和运动时术后各时间点患者VAS评分降低,观察组在术后3 d、术后1个月时身体舒适度更佳、情绪更乐观、有更好的自理能力和疼痛控制能力;观察组患者舒芬太尼的使用量、PCIA按压次数、镇痛补救率要低于对照组。差异有统计学意义(P<0.05)。结论右美托咪定混合罗哌卡因TPVB在全麻胸腔镜肺癌根治术后镇痛中的效果较好,能提高患者的术后康复质量,值得临床推广。     

超声引导下肋下前路腰方肌阻滞对后腹腔镜肾脏手术后镇痛效果的影响

目的观察和比较超声引导下肋下前路腰方肌阻滞(QLB)与低位胸椎旁神经阻滞(TPVB)用于后腹腔镜肾脏手术后镇痛的效果。方法择期行后腹腔镜肾脏手术患者70例,男38例,女32例,年龄18～65岁,BMI 18～24 kg/m~2,ASAⅠ或Ⅱ级。随机分为肋下前路QLB组(QLB组)和低位TPVB组(TPVB组),每组35例。QLB组行超声引导下患侧肋下前路QLB,TPVB组行超声引导下患侧T_(10)横突水平TPVB,两组分别注入0.33%罗哌卡因30 ml,注药后20 min测定感觉阻滞平面。两组术后行羟考酮PCIA。记录术后0～24 h和24～48 h镇痛泵用量、有效按压次数、总按压次数;记录术后2、6、12、24、36、48 h静息时和运动时的NRS评分;记录术后48 h内补救镇痛和低血压、肌力减退、恶心呕吐、嗜睡等不良反应发生情况。结果 QLB组阻滞平面为T_5—L_2,TPVB组为T_5—T_(12)。QLB组术后0～24 h和24～48 h镇痛泵用量明显低于TPVB组(P0.05),有效按压次数和总按压次数明显少于TPVB组(P0.05),术后12、24、36、48 h运动时NRS评分明显低于TPVB组(P0.05),术后48 h内补救镇痛、恶心呕吐和嗜睡发生率明显低于TPVB组(P0.05)。两组低血压和肌力减退发生率差异无统计学意义。结论与低位TPVB比较,超声引导下肋下前路QLB联合羟考酮PCIA在后腹腔镜肾脏手术后镇痛的效果更显著,持续作用时间更长,不良反应更少。     

不同剂量地塞米松对罗哌卡因神经阻滞作用的影响

目的比较不同剂量地塞米松复合罗哌卡因神经阻滞对罗哌卡因阻滞时效的影响。方法 60例内、外踝关节骨折拟行手术患者随机均分为三组。所有患者均在神经刺激器定位下行腰丛-坐骨神经阻滞麻醉。A组:0.4%罗哌卡因50ml;B组:0.4%罗哌卡因50ml加入地塞米松5mg;C组:0.4%罗哌卡因50ml加入地塞米松10mg。观察并记录腰丛、坐骨神经感觉阻滞起效时间、运动阻滞起效时间、感觉阻滞持续时间、运动阻滞持续时间。观察并记录三组患者术后24、48h镇痛泵的舒芬太尼用量、按压总次数和有效次数,记录三组患者术后12、24、36、48h的数字疼痛分级法(NRS)评分及恶心、呕吐、皮肤瘙痒、呼吸抑制等不良反应的发生率。结果 A组感觉阻滞持续时间和运动阻滞持续时间明显短于B、C组,且B组明显短于C组(P<0.01)。A组患者术后12、24h的NRS评分[(5.2±1.3)、(3.4±0.5)分]明显高于B组的[(1.1±0.3)、(1.6±0.6)]分和C组的[(0.4±0.1)、(1.0±0.2)]分(P<0.05)。A组患者按压总次数和有效次数、48h舒芬太尼用量明显多于B、C组(P<0.05)。结论 5和10mg地塞米松均能延长0.4%罗哌卡因腰丛-坐骨神经阻滞作用时间,且10mg作用更明显。     

超声引导下竖脊肌平面阻滞和胸椎旁神经阻滞用于胸腔镜下肺叶切除术的比较

目的比较超声引导下竖脊肌平面阻滞(erector spinae plane block,ESPB)和胸椎旁神经阻滞(thoracic paravertebral nerve block,TPVB)应用于胸腔镜下肺叶切除术中血流动力学变化及术后联合PCIA的效果。方法选择行胸腔镜下肺叶切除术的患者60例,男38例,女22例,年龄18~64岁,BMI 18~24 kg/m^2,ASAⅠ或Ⅱ级,随机分为ESPB组(E组)和TPVB组(T组),每组30例。E组术前0.4%罗哌卡因25 ml行超声引导下单次ESPB,T组术前0.4%罗哌卡因25 ml行单次TPVB。罗哌卡因注入20 min后用冰块测定阻滞平面。术毕两组均给予PCIA至术后48 h。记录穿刺时间、深度;记录术中血管活性药使用情况、丙泊酚、瑞芬太尼用量;记录镇痛泵首次按压时间、有效按压次数、曲马多补救例数;记录胸闷、皮肤瘙痒等术后不良反应的发生情况。结果与T组比较,E组穿刺时间明显缩短(P<0.05),穿刺深度明显变浅(P<0.05),术中去氧肾上腺素使用率明显降低(P<0.05)。两组术中丙泊酚、瑞芬太尼用量、镇痛泵首次按压时间、有效按压次数、曲马多补救率及术后不良反应差异无统计学意义。结论超声引导下ESPB较TPVB操作更简单快捷,术中低血压发生率更低,术后两种阻滞联合PCIA均能为胸腔镜肺叶切术患者提供有效的镇痛。     

罗哌卡因联合地塞米松腹腔内喷洒对腹腔镜胆囊切除术后疼痛的影响

目的探讨罗哌卡因联合地塞米松腹腔内喷洒对腹腔镜胆囊切除术(LC)后疼痛的影响。方法择期全凭静脉麻醉下行LC患者75例,随机均分为三组,建立气腹后向腹腔胆囊床分别喷洒生理盐水30ml(C组)、0.5%罗哌卡因30ml(R组)或0.5%罗哌卡因30ml复合地塞米松10mg(D组)。记录患者术后4、24、48h的切口、内脏、肩部静息和活动时VAS评分、术后恶心呕吐(PONV)的分级和术后追加镇痛药情况。结果 (1)与C组相比,D组患者术后24h和48h的切口静息和活动时VAS评分均明显降低(P<0.01),R组患者仅术后24h的切口静息和活动时VAS评分明显降低(P<0.05或P<0.01);与R组相比,D组患者术后24h和48h的切口静息和活动时VAS评分均明显降低(P<0.01)。(2)与C组相比,R、D组术后4h和24h的内脏静息和活动时VAS评分均明显降低(P<0.01),D组术后24h和48h的肩部静息和活动时VAS评分均明显降低(P<0.01);与R组相比,D组术后48h的肩部静息和活动时VAS评分均明显降低(P<0.05)。结论罗哌卡因联合地塞米松腹腔内喷洒可增强罗哌卡因的术后镇痛效果和延长镇痛时间,但对术后早期(术后4h)切口痛缓解不明显。     

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.