胃癌术后肺部感染列线图预测模型的构建

目的：研究胃癌术后发生肺部感染的相关危险因素,并构建列线图预测模型。方法 ：回顾性分析2010～2020年我院行手术治疗的330例胃癌患者的相关临床资料,筛选可能引起术后肺部感染的因素,采用Logistic回归进行危险因素分析,并构建列线图预测模型。采用校正曲线、一致性指数（c指数）和决策曲线分析（DCA）评价预测准确性、鉴别能力和临床有用性。结果：多因素Logistic回归分析显示年龄、吸烟史、慢性呼吸系统疾病史、肺功能锻炼依从性、腹腔镜手术、术中失血量是胃癌术后发生肺部感染的独立预测因素。依据独立危险因素所构建的列线图,校准曲线提示有较好的一致性,C-index为0.878(95%CI:0.801～0.956),ROC曲线下面积（AUC）为0.878,提示该列线图预测模型具有良好的区分度和校准度。DCA曲线表明该列线图有较好的临床获益。结论：根据胃癌术后发生肺部感染的相关独立危险因素构建的列线图预测模型,有助于对高危人群进行围手术期干预,减少术后肺部感染发生率。     

股骨头坏死行全髋关节置换术后输血的危险因素分析及列线图预测模型建立

目的：探讨股骨头坏死行全髋关节置换术后输血的危险因素,构建此类患者术后输血风险的列线图预测模型。方法：回顾性研究2019年1月至2020年12月因股骨头坏死行初次全髋关节置换的237例患者的病例资料,根据术后是否输血分为输血组60例,未输血组177例,术后输血率为25.3%。收集两组性别、体重指数（BMI）、麻醉方式、术前血红蛋白水平、手术时长、出血量等资料,运用多因素logistic回归分析法分析导致术后输血的危险因素,而后利用R软件构建股骨头坏死全髋关节置换术后输血的列线图预测模型,并绘制受试者操作特征（ROC）曲线来评估列线图模型区分度。结果：多因素分析显示,骨质疏松、术前血红蛋白降低、手术时长、出血量、术后1 d血钙降低是股骨头坏死行全髋关节置换术后输血的危险因素。通过R软件绘制列线图预测模型及ROC曲线,得到曲线下面积（AUC）为0.891,表明该预测模型有较好的区分度,预测术后输血风险与实际发生风险一致性较好。结论：基于骨质疏松、术前血红蛋白降低、手术时长、出血量、术后1 d血钙降低5项独立危险因素构建的预测股骨头坏死患者行全髋关节置换术后输血风险的列线图模型具有良好的区分...     

个体化预测老年髋部骨折患者术后谵妄风险

[目的]通过分析老年髋部骨折患者术后谵妄的相关危险因素,建立并验证个体化预测老年髋部骨折术后谵妄风险的列线图模型。[方法]纳入2013年1月～2018年3月于淄博市中心医院行手术治疗的老年髋部骨折患者257例,收集临床资料。应用单因素及多因素Logistic回归模型,分析老年髋部骨折患者术后谵妄的独立危险因素。应用R软件构建预测老年髋部骨折患者术后谵妄风险的列线图模型,并进行验证。[结果]多因素Logistic回归分析显示,年龄(OR=1.143,95%CI:1.076～1.214)、2型糖尿病(OR=4.591,95%CI:2.14～9.846)、ASA评分III级(OR=4.262,95%CI:1.600～11.352)、ASA评分IV级(OR=5.396,95%CI:1.868～15.583)、全身麻醉(OR=1.281,95%CI:1.066～1.540)及手术时间(OR=1.018,95%CI:1.001～1.035)是老年髋部骨折患者术后谵妄的独立危险因素(P0.05)。对列线图模型进行验证,ROC曲线显示该模型预测老年髋部骨折患者术后谵妄风险的曲线下面积为0.818(95%CI:0.752～0.885);校准曲线为斜率接近于1的直线,Hosmer-Lemeshow拟合优度检验(x~2=8.760,P=0.363)均显示该模型预测老年髋部骨折患者术后谵妄风险具有良好准确度。[结论]本研究基于年龄、2型糖尿病、ASA分级、麻醉方式及手术时间这5项老年髋部骨折患者术后谵妄的独立危险因素,构建的预测老年髋部骨折患者术后谵妄风险的列线图模型,具有良好的区分度与准确度,可为临床个体化防治老年髋部骨折患者术后谵妄提供科学指导。     

输尿管软镜碎石术后尿路感染的危险因素分析及预测模型构建

目的:分析影响输尿管软镜碎石术后尿路感染的危险因素,建立列线图预测模型。方法:采用便利抽样法,选取2019年4月—2021年7月阜南县人民医院收治的327例行输尿管软镜碎石术患者为研究对象,根据术后30 d内是否发生尿路感染分为感染组与未感染组,采用多因素logistics回归模型筛选术后尿路感染的独立影响因素,基于独立影响因素建立列线图预测模型,并评估模型的区分度与准确度。结果:输尿管软镜碎石术患者术后尿路感染发生率为14.37%（47/327）;多因素logistic回归分析显示,术前尿路感染、合并糖尿病、留置尿管时间>7 d、肾盂内压>30 mmHg为影响术后尿路感染的独立危险因素（P<0.05）,预防性应用抗菌药物为保护性因素（P<0.05）;基于输尿管软镜碎石术后尿路感染的独立影响因素建立列线图预测模型,内部验证结果显示列线图模型的校准曲线预测值与实际值基本一致,Hosmer-Lemeshow拟合优度检验χ²=8.199,P=0.315,ROC曲线下面积为0.805（95%CI:0.729～0.877）,DCA曲线分析阈值范围为0...     

高龄患者髋关节置换术后谵妄的发生率及危险因素分析

目的 探讨行髋关节置换术的高龄患者术后谵妄的发生率及危险因素.方法 选择2009年9月至2010年2月,择期行髋关节置换术患者120例.术前访视患者,术后当天,术后1、2、3d密切随访患者,用谵妄评定法进行谵妄评估.记录患者一般情况、病史、合并症、手术时间、术中失血量、术中输库存血量、术后疼痛评分及谵妄的发生情况,建立数据库.根据是否发生谵妄分为谵妄组和对照组.结果 术后发生谵妄28例,发生率为23.33%.多因素Logistic逐步回归分析高龄、术前合并肺心病、术前合并肺部感染、全身麻醉、术后低氧血症为谵妄的危险因素(P＜0.05).结论 高龄、术前合并肺心病、术前合并肺部感染、全身麻醉、术后低氧血症是术后谵妄的独立危险因素.     

高龄冠心病患者冠状动脉旁路移植术后缺血性卒中风险预测模型的建立与评价北大核心CSCD

目的探讨我国高龄(年龄≥75岁)冠心病患者冠状动脉旁路移植术后缺血性卒中的危险因素,建立相关风险预测模型并进行评价。方法回顾性纳入2015年1月至2021年9月期间就诊于首都医科大学附属北京安贞医院,拟行冠状动脉旁路移植术的1553例高龄冠心病患者,其中男1121例(72%),女432例(28%);中位年龄77(75,78)岁,收集其临床资料。通过单因素分析和多因素logistic回归分析,探讨影响高龄冠心病患者旁路移植术后缺血性卒中的危险因素,建立风险预测模型,构建列线图,并检验模型的区分度和校准度。结果全部患者均完成冠状动脉旁路移植术,术后发生缺血性卒中35例,发生率2.25%(35/1553)。多因素logistic回归分析结果显示:糖尿病(0R=2.61,95%CI 1.31~5.32)陈旧性心肌梗死(0R=3.62,95%CI:1.61~7.63)、收缩压(0R=1.03,95%CI:1.01~1.04)、椎动脉狭窄程度(0R=1.01,95%CI:1.00~1.02)是导致冠状动脉旁路移植术患者术后缺血性卒中的独立危险因素。通过列线图呈现模型,采用ROC曲线评价模型区分度,测得ROC曲线下面积为0.757,区分度较优。行Hosmer-Lemeshow拟合优度检验评价模型校准度(χ^(2)=6.209,P=0.624)具有较好的一致性。结论糖尿病、陈旧性心肌梗死、收缩压和椎动脉狭窄程度是高龄冠心病患者冠状动脉旁路移植术后缺血性卒中的独立危险因素,由此建立的风险预测模型具有良好的区分度和校准度。     

血清IL-8、VEGF水平与下肢动脉硬化闭塞症患者支架植入术后1年内支架内再狭窄的关系

背景与目的 支架植入术是治疗下肢动脉硬化闭塞症（ASO）的主要治疗方式之一,可有效恢复血管畅通,改善患者临床症状,但部分患者术后1年内易出现支架内再狭窄。支架内再狭窄可导致患者较差的预后,因此明确影响ASO术后支架再狭窄的病理机制具有重要意义。血清白细胞介素8（IL-8）与血管内皮生长因子（VEGF）分别是反映机体炎症和血管内皮功能的指标,与ASO的发生关系密切,但是否与ASO患者支架植入术后支架再狭窄相关尚不明确。鉴于此,本研究对IL-8、VEGF水平与ASO患者支架植入术后1年内支架内再狭窄的关系进行探讨,并建立预测支架植入术后1年内支架内再狭窄的列线图模型。方法 选取2020年1月—2022年10月河南省南阳市第一人民医院血管外科接受支架植入手术治疗的100例ASO患者为研究对象,术后随访1年,根据随访结果将受试者分为再狭窄组和未再狭窄组。收集受试者人口学特征、术后血清IL-8与VEGF水平及其他相关指标等。采用单因素和Logistic回归分析影响支架植入术后1年内支架内再狭窄的危险因素。基于危险因素构建预测支架植入术后1年支架内再狭窄的风险列线图预测模型,并对构建的预测模型进行验证。结果 随访期间失访4例,失访率为4.00%（4/100）。96例患者中29例患者发生支架内再狭窄,支架内再狭窄率为30.21%（29/96）。Logistic回归分析结果显示,年龄≥60岁（OR=4.191）、Fontaine分期（Ⅳ期）（OR=2.863）、完全闭塞（OR=2.445）、下肢血管病变长度≥7.15 cm（OR=3.343）、术后IL-8≥1.02 ng/mL（OR=6.482）、术后VEGF≥158.37 pg/mL（OR=10.402）是影响支架植入术后1年支架内再狭窄的独立危险因素（均P<0.05）。对基于以上因素构建的列线图预测模型的验证结果显示,校正曲线贴近于理想曲线;C指数为0.857（95% CI=0.785~0.952）;受试者工作特征（ROC）曲线结果显示,列线图风险模型预测支架植入术后1年支架内再狭窄的ROC曲线下面积为0.852（95% CI=0.631~0.979）,敏感度、特异度分别为92.50%、78.40%。结论 ASO患者支架植入术后血清IL-8、VEGF水平与支架内再狭窄的发生率关系密切,术后血清IL-8、VEGF水平越高,患者术后支架内再狭窄的发生风险越高,以此为基础构建的列线图模型预测模型有助于临床医生对ASO患者提供更好的治疗和随访方案。     

老年股骨颈骨折半髋关节置换术后输血预测模型的建立

目的分析老年股骨颈骨折患者半髋关节置换术后输血的危险因素,建立老年股骨颈骨折患者半髋关节置换术后输血的列线图预测模型。 方法回顾性分析2016年1月至2020年6月江苏省苏北人民医院股骨颈骨折行半髋关节置换术的235例患者。纳入标准：年龄≥60岁,新发、单侧股骨颈骨折;手术方式为半髋关节置换术。排除标准：合并全身其他骨折;术前输血;合并凝血功能障碍或者其他血液系统疾病;身体状况较差无法耐受手术者;病历资料不完整者。根据术后是否输血,分为输血组和未输血组。收集其临床资料,包括性别、年龄、身体质量指数(BMI)、高血压、糖尿病、冠心病、脑卒中、吸烟、饮酒、术前血红蛋白(Hb)、术前血小板(PLT)、术前白蛋白、术前凝血功能、术前抗凝药使用、骨折Garden分型、受伤至手术时间、假体类型、术后是否引流、术后血钙浓度、美国麻醉师协会(ASA)分级、麻醉方式、手术时间、术中出血量等。应用单因素和多因素logistic回归模型筛选术后输血的独立危险因素;通过R软件构建列线图预测模型,并绘制出受试者工作特征(ROC)曲线及校准曲线来评价模型的区分度和准确度。 结果本研究共纳入235例研究对象,输血组60例,输血率为25.5%。两组患者在术前Hb(χ²＝62.831)、麻醉方式(χ²＝6.539)、手术时间(χ²＝79.392)、术中出血量(χ²＝74.515)、假体类型(χ²＝5.631)方面的组间差异有统计学意义(均为P<0.05)。多因素logistic回归模型分析显示：术前Hb水平(Hb<100 g/L)、手术时间延长(时间≥60 min)、术中出血量增多(出血量≥200 ml)是老年股骨颈骨折患者半髋关节置换术后输血的独立危险因素(均为P<0.05)。列线图预测模型曲线下面积AUC为0.95,校准曲线的斜率接近1,提示该预测模型具有良好的区分度和准确度。 结论基于术前血红蛋白、手术时间、术中出血量这3项独立危险因素构建的老年股骨颈骨折患者半髋关节置换术后输血预测的列线图模型具有良好的区分度和准确度,望为临床上早期甄别术后高风险输血患者提供指导意义。     

社区老年慢性病患者认知衰弱风险预测模型的构建及验证

目的 探索社区老年慢性病患者发生认知衰弱的危险因素,为针对性干预提供参考.方法 对674例社区老年慢性病患者,采用一般资料调查问卷、衰弱表型、蒙特利尔认知评估量表、临床痴呆评定量表、简易营养评价精法问卷以及简版老年人抑郁量表进行调查;行单因素及多因素分析提取认知衰弱影响因素,基于主要影响因素构建认知衰弱风险列线图预测模型;运用Bootstrap法验证模型效能.结果 社区老年慢性病患者认知衰弱检出率为33.5％;年龄、独居、营养不良、抑郁、体育锻炼为其主要影响因素(均P＜0.05);分类校准曲线贴合紧密,ROC曲线下面积为0.970.结论 社区老年慢性病患者认知衰弱发生率较高,高龄、独居、营养不良及抑郁是认知衰弱发生的独立危险因素,体育锻炼为保护性因素;构建的列线图预测模型精准度与区分度良好,可用于社区老年慢性病患者认知衰弱筛查.     

结直肠癌术后肠梗阻的危险因素分析及预测模型建立

目的构建结直肠癌(CRC)术后肠梗阻(POI)的列线图风险预测模型并进行验证。方法回顾性收集2018年6月至2019年8月接受CRC手术患者413例的围术期临床资料,年龄≥18岁,ASAⅠ—Ⅲ级。通过LASSO回归和多因素Logistic回归分析筛选独立危险因素,以此建立列线图模型。通过C-index验证模型的区分度;通过Calibration校正曲线验证模型的一致性;并通过决策曲线分析(DCA)以确定模型的临床有效性。结果共有404例CRC患者纳入分析,其中POI患者74例(18.3%)。列线图风险预测模型中包括开腹手术、术中未用非甾体类抗炎药(NSAIDs)、术前白蛋白(Alb)37.55 g/L和术前球蛋白(Glb)≥28.35 g/L。经内部验证,该模型的C-index为0.799(95%CI 0.746～0.852);Calibration校正曲线显示较好的一致性。DCA曲线表明当POI发生的风险阈值超过4%时,此列线图具有临床使用价值。结论基于开腹手术、术中未用NSAIDs、术前Alb37.55 g/L和术前Glb≥28.35 g/L这4个预测因素构建的列线图预测模型对CRC患者发生POI风险有良好的预测性能。     

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.