北京地区妇幼专科医院医务人员对椎管内分娩镇痛认知情况的调查

目的 调查北京地区妇幼专科医院部分医务人员对椎管内分娩镇痛的认知情况,为进一步开展分娩镇痛提供决策依据。
方法 采用自行设计的问卷于2019年6—8月对北京地区22家妇幼专科医院医务人员进行椎管内分娩镇痛认知和应用情况的问卷调查。调查问卷内容包括3个部分共23个条目。
结果 本次调查共收集到调查问卷3 786份,其中95.25%的医务人员听说过椎管内分娩镇痛,清楚了解为39.65%。87.63%的医务人员认为目前最有效的分娩镇痛方法为椎管内分娩镇痛。83.64%的医务人员赞成椎管内分娩镇痛,15.75%的医务人员不支持也不反对分娩镇痛。96.67%的麻醉科医师了解椎管内分娩镇痛,而产科医师和助产士分别只有64%和78.82%了解分娩镇痛。22家妇幼专科医院2018年度椎管内分娩镇痛率最低为2.12%,最高为93.98%,平均为46.25%,其中14家公立妇幼专科医院椎管内分娩镇痛率为43.21%,8家非公立妇幼专科医院为88.63%,分娩镇痛改剖宫产比率为6.20%。
结论 北京地区各妇幼专科医院分娩镇痛率极不均衡,非公立医院分娩镇痛开展比例明显高于公立医院。麻醉科医师、产科医师和助产士对椎管内分娩镇痛了解程度明显高于其他科室人员。     

氢吗啡酮硬膜外分娩镇痛对产时发热的影响

目的 探究氢吗啡酮用于硬膜外分娩镇痛对产妇产时发热、镇痛效果和不良反应的影响。
方法 选择无椎管内麻醉禁忌证并要求硬膜外分娩镇痛的单胎、足月、头位初产妇425例,年龄20～40岁,BMI 20～30 kg/m²,ASA Ⅰ或Ⅱ级,孕期37～42周。采用随机数字表法将产妇分为三组：罗哌卡因组（R组,n=145）、氢吗啡酮组（H组,n=142）和罗哌卡因+氢吗啡酮组（RH组,n=138）。采用患者硬膜外镇痛（PCEA）行分娩镇痛,R组、H组和RH组镇痛泵药物浓度分别为0.1%罗哌卡因、氢吗啡酮40 μg/ml和0.1%罗哌卡因+氢吗啡酮15 μg/ml。记录镇痛前、镇痛后1、2、3、4、5 h、胎儿娩出即刻及产后1 h的VAS疼痛评分。记录产时发热例数、阴道检查次数、产程时间、破膜到胎儿娩出的时间、镇痛时间、麻醉药用量、PCEA有效按压次数和总按压次数、新生儿体重、新生儿1 min和5 min Apgar评分。取脐动脉血1 ml行血气分析,记录pH、BE值、Lac浓度。记录恶心、呕吐、头晕、寒战、瘙痒、嗜睡、低血压等不良反应发生情况。
结果 与R组比较,H组和RH组镇痛后2、3、4、5 h和胎儿娩出即刻VAS疼痛评分均明显降低（P<0.05）;H组产时发热率、脐动脉血pH值、寒战发生率明显降低,PCEA有效按压次数、PCEA总按压次数明显减少,恶心、呕吐、头晕、瘙痒、嗜睡发生率明显升高（P<0.05）;RH组破膜到胎儿娩出的时间、镇痛时间明显延长,脐动脉血pH值明显降低,恶心、呕吐发生率明显升高（P<0.05）。与H组比较,RH组产时发热率、寒战发生率明显升高,破膜到胎儿娩出的时间明显延长,氢吗啡酮用量明显减少,头晕、嗜睡发生率明显降低（P<0.05）。
结论 氢吗啡酮用于硬膜外分娩镇痛产妇产时发热率低,镇痛效果良好,但不良反应发生率较高。     

2010—2020年科学引文索引中收录分娩镇痛相关文献的计量学分析

目的 通过文献计量学的方法分析和探讨分娩镇痛领域的研究现状、发展趋势和热点。
方法 在Web of Science（WoS）核心数据库中检索2010—2020年发表的分娩镇痛相关文献,采用文献计量学的方法,分析纳入文献的年度发文量、H指数、被引频次、发文国家、发文机构、发文作者、发文期刊、研究方向等基本概况;采用CiteSpace软件对2010—2020年分娩镇痛相关文献的总体特征进行分析。
结果 共纳入文献1 508篇,2010—2020年分娩镇痛相关文献发文量整体呈上升趋势,美国发文量429篇（28.4%）,中国发文量165篇（10.9%）,中国H指数排名第5、被引频次排名第4。椎管内镇痛技术、镇痛药物的输注模式、静脉分娩镇痛、超声引导下的定位穿刺技术等是近年来的研究热点,而分娩镇痛对产时发热、产后抑郁等的影响也受到关注。
结论 2010—2020年期间分娩镇痛领域发展迅速,美国处于研究领先地位,而我国需在发文量基础上提高论文质量。分娩镇痛新技术及分娩镇痛对母婴短期和长期预后的影响将成为今后研究的焦点。     

程控间歇脉冲输注联合硬膜外分娩镇痛时产妇爆发痛的相关因素分析

目的 分析程控间歇脉冲输注联合患者自控硬膜外分娩镇痛模式下产妇发生爆发痛的相关因素。
方法 选择行分娩镇痛的产妇215例,年龄20～45岁,孕期≥37周,单胎头位,ASA Ⅱ或Ⅲ级。行硬膜外穿刺置管后接入电子镇痛泵,参数设置：0.08%罗哌卡因+舒芬太尼0.4 μg/ml,负荷剂量15 ml,脉冲剂量10 ml/h,单次追加剂量8 ml,锁定时间30 min,极限量30 ml/h。当产妇出现爆发痛时给予0.125%罗哌卡因+舒芬太尼0.4 μg/ml共10 ml追加,根据产妇是否发生爆发痛分为两组：爆发痛组和无爆发痛组。记录产妇一般情况和分娩镇痛相关指标。采用单因素方差分析和二分类Logistic回归分析筛选爆发痛的相关因素。
结果 93例（43.2%）产妇发生爆发痛。与无爆发痛组比较,爆发痛组产间发热率明显升高、分娩镇痛满意度明显降低（P<0.05）。两组器械助产率差异无统计学意义。Logistic回归分析显示,硬膜外镇痛中断、镇痛15 min后NRS评分增加和第一产程时间延长是发生爆发痛的独立相关因素。
结论 镇痛15 min后NRS评分增加、硬膜外镇痛中断、第一产程时间延长是硬膜外分娩镇痛后发生爆发痛的独立相关因素。     

纳布啡复合罗哌卡因连续硬膜外阻滞用于分娩镇痛的效果

目的 研究纳布啡复合罗哌卡因用于硬膜外分娩镇痛的效果。
方法 自愿选择分娩镇痛的单胎初产妇180例,年龄20~40岁,BMI 18~35 kg/m²,ASA Ⅰ或Ⅱ级,采用随机数字表分为纳布啡组（NR组）和舒芬太尼组（SR组）,每组90例。NR组产妇在宫口开至约2 cm时,给予0.3 mg/ml纳布啡复合0.1%盐酸罗派卡因行患者自控硬膜外镇痛（PCEA）。SR组产妇给予0.3 μg/ml舒芬太尼复合0.1%盐酸罗派卡因行PCEA。记录镇痛起效时间、首次PCA时间、PCA药物总量和罗哌卡因消耗量等。观察镇痛前（T₀）、镇痛30 min（T₁）、60 min（T₂）、宫口开全（T₃）、分娩时（T₄）和产后2 h（T₅）时VAS评分、Ramsay镇静评分、改良Bromage评分、BP、HR、SpO₂ 。记录新生儿脐动脉血气和神经适应能力评分（NBNA）、产妇首次泌乳时间、出血量和恶心呕吐、皮肤瘙痒等不良反应发生率。
结果 与SR组比较,NR组镇痛起效时间明显增快（P＜0.05）,首次PCA时间明显缩短（P＜0.05）,PCA药物总量、PCA按压次数、有效按压次数和罗哌卡因消耗量明显增加（P＜0.05）,T₃时VAS评分明显升高（P＜0.05）。两组产妇Ramsay镇静评分、改良Bromage评分、BP、HR、SpO₂ 、首次泌乳时间等差异无统计学意义。两组新生儿脐动脉血气和NBNA评分等差异无统计学意义。
结论 与舒芬太尼比较,纳布啡用于硬膜外分娩镇痛起效较快,但在宫口开全时VAS评分和罗哌卡因消耗量较高。两者都能明显降低分娩疼痛,并且都对患儿脐动脉血气和NBNA评分无影响。     

硬膜外间歇脉冲注入技术用于分娩镇痛的效果

目的 探讨硬膜外间歇脉冲注入技术（PIEB）在产妇自控硬膜外分娩镇痛中的效果及对分娩结局的影响。
方法 选择行硬膜外分娩镇痛的单胎、头位、足月妊娠产妇100例,年龄18～38岁,BMI 20～32 kg/m²,ASA Ⅰ或Ⅱ级,采用随机数字表法分为两组：PIEB组和连续硬膜外输注组（CEI组）,每组50例。两组镇痛药配方均为0.08％罗哌卡因＋0.4 μg/ml舒芬太尼。PIEB组参数设置：脉冲频率每小时1次,剂量10 ml,注药速率400 ml/h,单次剂量10 ml,间隔20 min。CEI组参数设置：背景输注速率10 ml/h,单次剂量10 ml,间隔20 min。记录产妇分娩镇痛前、镇痛后1、2、3、5 h、宫口开全和分娩时的VAS疼痛评分;产妇首次按压时间、按压次数、镇痛泵用药总量、镇痛时间;总产程时间、产后出血量、新生儿Apgar评分、产妇对分娩镇痛效果满意度评分;感觉阻滞平面达T4的例数、改良Bromage评分;以及低血压、恶心呕吐等不良反应发生情况。
结果 与分娩镇痛前比较,分娩镇痛后两组产妇VAS疼痛评分明显降低（P<0.05）。与CEI组比较,PIEB组镇痛后2、3、5 h、宫口开全、分娩时VAS疼痛评分均明显降低（P<0.05）,首次按压时间明显延迟（P<0.01）,按压次数、镇痛泵用药总量明显减少（P<0.01）。与CEI组比较,PIEB组产妇满意度评分明显增高（P<0.01）,感觉阻滞平面达T4的产妇比例明显升高（P<0.05）。两组总产程时间、产后出血量、新生儿Apgar评分差异无统计学意义。两组低血压和恶心呕吐等不良反应发生率差异无统计学意义。
结论 PIEB可安全有效地用于产妇自控硬膜外分娩镇痛,其效果优于连续硬膜外输注,产妇满意度高,且不影响分娩结局。     

硬膜外分娩镇痛对产妇胃窦排空的影响

目的 观察硬膜外分娩镇痛对产妇胃窦排空的影响。
方法 选择孕足月初产妇87例,年龄20～40岁,BMI 20～40 kg/m²,ASA Ⅱ 或 Ⅲ 级。根据自愿是否需要分娩镇痛分为两组：镇痛组和对照组,其中镇痛组43例,对照组44例。镇痛组在L2-3行硬膜外穿刺置管术,置管成功后连接硬膜外自控镇痛泵,镇痛药物配方为0.08%罗哌卡因+舒芬太尼0.4 μg/ml。对照组不使用分娩镇痛。超声检查胃窦排空后给予碳水化合物饮料300 ml,分娩期间产妇不再进食其他食物饮料。记录胃窦排空即刻、饮用碳水化合物后5、30、60、120 min 和宫口开全时的胃窦横截面积（CSA）、单位体重胃容量（GV_W）和VAS疼痛评分。记录第一和第二产程时间、胃窦再次排空所需时间。记录分娩期间恶心和中转剖宫产情况。记录新生儿1 min和5 min的Apgar评分。记录产后住院时间。
结果 与对照组比较,镇痛组饮用碳水化合物后30、60、120 min和宫口开全时CSA和GV_W明显减小（P<0.05）,胃窦排空即刻、饮用碳水化合物后5、30、60、120 min和宫口开全时VAS疼痛评分明显降低（P<0.05）胃窦再次排空时间明显缩短（P<0.05）。两组第一和第二产程时间、恶心发生率、新生儿出生后1 min和5 min的Apgar评分、产后住院时间差异无统计学意义。
结论 硬膜外分娩镇痛会加快产妇胃窦排空,产程中饮用300 ml的碳水化合物饮品对母婴结局无不良影响。     

腰椎术后手术部位感染的危险因素分析及列线图模型建立

目的 探讨开放性腰椎后入路手术患者术后手术部位感染（SSI）的相关危险因素,并建立与验证术后SSI的列线图风险预测模型。
方法 选择2017年1月至2021年12月行开放性腰椎后入路手术的患者920例,男422例,女498例,年龄≥18岁,BMI≥18.5 kg/m²,ASA Ⅰ—Ⅳ级。将患者按照7∶3随机分为训练数据集和验证数据集,并基于训练数据集建立预测模型。采用Lasso回归结合二元Logistic回归最终筛选的预测因素构建列线图模型。使用C指数、校准曲线及决策曲线（DCA）等对列线图模型的区分度、校准度及临床适用度进行分析评估。
结果 本研究中发生SSI的有17例（1.85%）,训练集中有10例（1.55%）,验证集中有7例（2.54%）。列线图模型中的预测因素包括术前低白蛋白血症（OR=36.928,95%CI 6.585～235.997,P<0.001）、肥胖（BMI≥28.0 kg/m²）（OR=4.994,95%CI 1.202～24.781,P=0.032）和术后3天内切口渗出（OR=6.133,95%CI 1.473～28.775,P=0.014）。该模型的C指数为0.879（95%CI 0.760～0.998）。校准曲线显示良好的一致性。DCA曲线分析显示当SSI发生风险阈值＞1%时,该列线图更具临床价值。
结论 术前低白蛋白血症、肥胖及术后3 d内切口渗出是行开放性腰椎后入路患者术后发生SSI的危险因素,基于以上危险因素构建的风险预测模型可以较好地预测术后SSI的发生。     

不同镇痛方法用于髋部或股骨干骨折患者椎管内麻醉摆放体位时镇痛效果的网状Meta分析

目的 采用网状Meta分析系统评价不同镇痛方法用于髋部或股骨干骨折患者椎管内麻醉摆放体位时的镇痛效果。
方法 计算机检索PubMed、Cochrane Library、Web of Science、EMbase、中国生物医学文献数据库(CBM)、中国知网、维普、万方，检索时间为建库至2022年8月，纳入髋部或股骨干骨折患者摆放体位和椎管内麻醉时实施镇痛的随机对照研究。由两名研究员独立进行文献筛选、资料提取和偏倚风险评价，采用Stata 17.0和RevMan 5.3软件进行统计分析。
结果 共纳入28篇文献，患者1 773例。累计排序概率曲线下面积（SUCRA）显示，降低摆放体位时VAS疼痛评分PENG阻滞（94.4%）效果最佳，其次是FIB联合IVA（83.8%）和FIB（71.1%）；降低椎管内麻醉时VAS疼痛评分PENG阻滞（98.2%）效果最佳，其次是FIB（71.1%）和FNB（55.6%）；缩短椎管内麻醉操作时间PENG阻滞（84.1%）效果最佳，其次是FNB（70.7%）和FIB（68.5%）；升高体位摆放质量评分PENG阻滞（99.1%）效果最佳，其次是FIB（73.1%）和FNB（52.9%）。
结论 神经阻滞或神经阻滞联合IVA可降低髋部或股骨干骨折患者体位摆放和椎管内麻醉时VAS疼痛评分、缩短麻醉操作时间和升高体位摆放质量评分。PENG阻滞对髋部或股骨干骨折患者摆放体位和椎管内麻醉时实施镇痛的效果最佳。     

基于随机森林算法建立非急诊大手术后延迟拔管的预测模型

目的 基于随机森林算法分析非急诊大手术后延迟拔管的影响因素，建立并验证术后延迟拔管的预测模型。
方法 回顾性收集2018年1月至2022年12月全麻下行非急诊大手术的7 528例患者的临床资料。根据术后2 h内是否拔管，将患者分为两组：非延迟拔管组（≤2 h）和延迟拔管组（>2 h）。将患者按照7∶3分为训练集和验证集，通过LASSO回归、Logistic回归筛选术后延迟拔管的预测因素，采用随机森林算法建立并验证预测模型。
结果 有123例（1.6%）出现术后延迟拔管。ASA分级、科室、术中使用氟比洛芬酯、右美托咪定、激素、术中出现低钙血症、重度贫血、术中输血、气道痉挛是术后延迟拔管的独立预测因素。基于随机森林算法建立的预测模型在验证集中的曲线下面积（AUC）为0.751（95%CI 0.742~0.778），敏感性98.1%，特异性41.9%。
结论 基于随机森林算法建立的非急诊大手术后拔管延迟的预测模型具有较好的预测性能，利用该模型有助于预防非急诊大手术后延迟拔管。     

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.