非心脏手术后延迟拔管的危险因素分析及预测模型建立

目的 探讨非心脏手术后延迟拔管的危险因素并建立预测模型。
方法 回顾性分析2020年9—10月接受非心脏手术且术后于PACU进行麻醉苏醒的1 009例患者临床资料。根据术后是否出现延迟拔管将患者分为两组：延迟拔管组（拔管时间＞1 h）和非延迟拔管组（拔管时间≤1 h）。采用LASSO回归和多因素Logistic回归建立预测模型，受试者工作特征（ROC）曲线、曲线下面积（AUC）和决策曲线分析评估该预测模型对非心脏手术后延迟拔管的预测价值。
结果 发生延迟拔管253例（25.1%）。多因素Logistic回归分析
结果 显示，ACCI评分（≥3分）、BMI（≤22.66 kg/m²）、术中罗库溴铵的使用、术中输血、手术时间（≥166 min）、留置导尿管、PACU内丙泊酚的使用和PACU内血管活性药物的使用是术后延迟拔管的独立危险因素（P＜0.05）。预测模型的AUC为0.730（95%CI 0.695～0.765， P<0.001），敏感性81.4%，特异性55.4%。决策曲线分析显示，该预测模型对延迟拔管的预测具有重要临床价值。
结论 ACCI评分（≥3分）、BMI（≤22.66 kg/m²）、术中罗库溴铵的使用、术中输血、手术时间（≥166 min）、留置导尿管、PACU内丙泊酚的使用和PACU内血管活性药物的使用是非心脏手术后延迟拔管的危险因素，基于以上危险因素建立的模型具有较好的预测价值。     

肾移植术后气管导管延迟拔管的危险因素分析

目的 探讨肾移植患者术后气管导管延迟拔管的危险因素及对预后的影响。
方法 回顾性分析2017年1月至2020年12月全麻下肾移植手术患者的电子病历资料366例,男261例,女105例,年龄18～64岁。根据拔除气管导管时间是否超过1 h分为两组：常规组和延迟组。采用单因素分析和多因素Logistic回归分析筛选肾移植术后延迟拔管的危险因素。
结果 有80例（21.9%）患者发生延迟拔管。与常规组比较,延迟组男性比例、亲属活体移植例数明显减少（P<0.05）,术前Hb、术前血钙明显降低（P<0.05）,冷缺血时间、麻醉时间明显延长（P<0.05）,诱导使用罗库溴铵和术中输血例数明显增加（P<0.05）,液体总入量、出血量明显增多（P<0.05）,拔管时间、PACU停留时间明显延长（P<0.05）。多因素Logistic回归分析显示,肾移植术后延迟拔管的独立危险因素为：术前Hb<113 g/L（OR=1.847,95%CI 1.076~3.171,P=0.026）、术前血钙<2.48 mmol/L（OR=2.293,95%CI 1.258~4.179,P=0.007）、冷缺血时间>10.5 h（OR=1.986,95%CI 1.139~3.464,P=0.016）和液体总入量>1 975 ml（OR=3.092,95%CI 1.795~5.324,P<0.001）。
结论 术前Hb<113 g/L、术前血钙<2.48 mmol/L、冷缺血时间>10.5 h、液体总入量>1 975 ml是肾移植术后延迟拔管的独立危险因素。     

基于机器学习的非心肺转流冠状动脉旁路移植术相关急性肾损伤的预测模型

目的 建立基于机器学习的非心肺转流冠状动脉旁路移植术相关的急性肾损伤（OPCABG-AKI）可解释性机器学习预测模型。
方法 回顾性收集2018—2021年行OPCABG的1 110例患者的临床资料。建立并比较8种机器学习模型,采用Python的SHAP模型解释包对预测性能最佳的黑箱模型进行解释性分析。将特征参数SHAP绝对值的平均值定义为该参数的重要性并进行排序;以SHAP值为依据确定各特征参数与OPCABG-AKI的关系;对主要风险因素进行单个特征量化分析;对模型中具有代表性的真阳性及真阴性样本进行独立的解释性分析。
结果 共有405例(36.5%)患者发生AKI。在8种机器学习模型中,随机森林（RF）预测模型性能最优,针对阳性样本的受试者工作特征曲线(ROC)下面积(AUC)为0.90(95%CI 0.86~0.94)。SHAP模型解释性分析结果显示术中尿量对RF模型的贡献最大,其次为诱导期循环变异系数、术中右美托咪定用量、术中舒芬太尼用量、术中低血压时间、术前血清肌酐基线、APACHE Ⅱ分数和年龄等。
结论 以随机森林集成学习算法构建模型可较好地预测OPCABG-AKI,模型中术中尿量等指标与OPCABG-AKI关系密切。     

超声引导下双侧阴部神经阻滞预防输尿管镜碎石术后导尿管相关膀胱刺激征的效果

目的 探讨超声引导下双侧阴部神经阻滞（PNB）预防全麻下输尿管镜碎石术后导尿管相关膀胱刺激征（CRBD）的效果。
方法 选择择期全麻下行输尿管镜碎石术的男性患者104例，年龄18～64岁，BMI 20～27 kg/m²，ASA Ⅰ或Ⅱ级。采用随机数字表法将患者分为两组：阻滞组和对照组，每组52例。阻滞组在麻醉诱导前予双侧PNB，对照组不做处理，两组麻醉诱导及维持方法相同。记录拔管后12 h内CRBD发生情况和严重程度。记录拔管即刻、拔管后30 min、4、8、12 h时VAS疼痛评分、躁动评分和Ramsay评分。记录拔管后12 h内曲马多追加情况。记录术后48 h内口干、寒战、恶心呕吐、呼吸抑制、过度镇静等不良反应的发生情况。
结果 拔管后12 h内，阻滞组CRBD发生率明显低于对照组（P<0.05），阻滞组CRBD严重程度明显低于对照组（P<0.05）。拔管即刻、拔管后30 min、4 h时，阻滞组VAS疼痛评分明显低于对照组（P<0.05）；拔管后30 min、4、8、12 h时，阻滞组躁动评分明显低于对照组（P<0.05）；拔管即刻、拔管后30 min、4、8 h时，阻滞组Ramsay评分明显高于对照组（P<0.05）。拔管后12 h内阻滞组曲马多追加率明显低于对照组（P<0.05）。术后48 h内阻滞组口干和恶心呕吐发生率明显低于对照组（P<0.05）。术后48 h内两组寒战、呼吸抑制和过度镇静发生率差异无统计学意义。
结论 超声引导下双侧PNB预防全麻下输尿管镜碎石术后患者CRBD的发生具有良好效果，有助于降低CRBD的发生率以及严重程度，且不良反应发生率更低。     

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。     

经皮穴位电刺激对双腔支气管插管患者术后咽喉痛的影响

目的 探讨经皮穴位电刺激（TEAS）对双腔支气管插管全麻患者术后咽喉痛（POST）的影响。
方法 选择2021年10月至2022年3月择期行双腔支气管插管全麻的手术患者103例，男45例，女58例，年龄18～64岁，BMI 18～28 kg/m²，ASA Ⅰ—Ⅲ级。采用随机数字表法将患者分为两组：TEAS组（n=51）和对照组（n=52）。TEAS组于麻醉诱导前30 min 在天突穴和双侧合谷穴行TEAS，至患者送至恢复室前停止；对照组放置电极片于相同穴位，但不进行电刺激。记录Mallampati分级、气管插管尝试次数、按压环状软骨、插管时阻力和双腔支气管导管（DLT）留置时间。记录拔管后1、6、24 h POST发生情况及严重程度、咽喉VAS疼痛评分和声嘶发生情况。
结果 与对照组比较，TEAS组拔管后1、6、24 h POST总发生率、POST 1级发生率和咽喉VAS疼痛评分明显降低（P<0.05），拔管后6 h POST 2级发生率明显降低（P<0.05）。两组拔管后1、6、24 h声嘶发生率差异均无统计学意义。
结论 经皮穴位电刺激天突穴和双侧合谷穴可明显降低双腔支气管插管患者术后咽喉痛的发生率、严重程度和咽喉VAS疼痛评分。     

咪达唑仑对术前中重度焦虑老年患者结直肠癌根治术后谵妄的影响

目的 探讨术前短期口服咪达唑仑对术前合并中重度焦虑老年患者结直肠癌根治术后谵妄的影响。
方法 选择择期行腹腔镜结直肠癌根治术的老年患者80例，男32例，女48例，年龄65～79岁，BMI 21～27 kg/m²，ASA Ⅱ或Ⅲ级，入院时状态特质焦虑量表（STAI-S）评分≥38分。采用随机数字表法将患者分为两组：对照组和咪达唑仑组，每组40例。咪达唑仑组予咪达唑仑7.5 mg每晚一次，连续服药3～4 d，直到术前1 d；对照组予外观相似的安慰剂半片。记录术前1 d STAI-S评分与术后3 d内谵妄的发生情况，记录入室时、麻醉诱导后30 min、1、2 h、拔管后30 min HR和MAP，记录术中丙泊酚、瑞芬太尼、右美托咪定用量及间羟胺使用情况，记录拔管后30 min、术后24、72 h视觉模拟评分（VAS）、曲马多使用情况以及拔管时间。
结果 与对照组比较，咪达唑仑组术前1 d STAI-S评分、术后谵妄发生率、术中间羟胺使用率、拔管后30 min、术后24 h VAS疼痛评分、曲马多使用率明显降低（P<0.05）。两组术中丙泊酚、瑞芬太尼、右美托咪定用量和拔管时间差异无统计学意义。
结论 术前口服咪达唑仑可有效降低合并术前中重度焦虑老年患者结直肠癌根治术后谵妄的发生。     

氨基末端脑钠肽对老年患者非心脏手术后肺部并发症的预测价值

目的 评估术前氨基末端脑钠肽（NT-pro BNP）对老年患者非心脏手术后肺部并发症（PPCs）的预测价值。
方法 前瞻性收集行非心脏手术老年患者174例，男118例，女56例，年龄≥65岁，ASA Ⅰ—Ⅲ级。于术前2 h测定静脉血中NT-pro BNP水平，采用全子集回归进行变量筛选，多因素Logistic回归构建模型。通过受试者工作特征曲线下（AUC）面积和决策分析曲线评价术前NT-pro BNP对PPCs的预测价值。
结果 有22例（12.6%）患者发生PPCs。全子集回归分析筛选出最终变量，纳入多因素Logistic回归模型中的变量为性别、ASA分级、胰腺手术、胃肠手术、泌尿手术、活动耐量、屏气试验分级、总输液量和术前NT-pro BNP。加入术前NT-pro BNP后，多因素Logistic回归模型的AUC由0.777增加至0.815（P<0.05）。决策分析曲线结果显示，在所有风险决策阈值下，加入术前NT-pro BNP后，多因素Logistic回归模型均可获得临床净获益。
结论 术前NT-pro BNP是老年患者非心脏手术PPCs的独立预测因子，可显著改善模型的预测性能，获得临床净获益，实现对老年患者非心脏手术PPCs的早期精准预测及风险分层。     

肝切除术后慢性疼痛的影响因素

目的：探讨肝切除术后慢性疼痛（CPSP）的影响因素。
方法：选择2019年6月至2021年5月择期行肝切除术的患者110例,男91例,女19例,年龄≥18岁,BMI 15～30 kg/m²,ASA Ⅱ或Ⅲ级。根据术后3个月是否诊断CPSP将患者分为两组：非CPSP组和CPSP组。单因素分析后将差异有统计学意义的指标纳入多因素Logistic回归,分析肝切除术CPSP的影响因素。采用回归系数以及常数项构建肝切除术CPSP的预测模型,绘制受试者工作特征（ROC）曲线并计算曲线下面积（AUC）,采用Hosmer-Lemeshow进行拟合优度检验。
结果：有42例（38%）患者肝切除术后发生CPSP。多因素Logistic回归分析显示,BMI≥25 kg/m²是发生CPSP的保护因素,手术时间≥3 h、术后1 d白细胞计数≥13×10⁹/L、术后24 h VAS疼痛评分≥4分是发生CPSP的危险因素。建立的预测模型的AUC为0.86,敏感性73.8%,特异性79.4%,Hosmer-Lemeshow拟合优度检验提示模型区分度和校准度均较好。
结论：BMI≥25 kg/m²是肝脏切除术发生CPSP的保护因素,手术时间≥3 h、术后1 d白细胞计数≥13×10⁹/L、术后24 h VAS疼痛评分≥4分是肝脏切除术发生CPSP的危险因素。     

非胃肠道日间手术患儿术后早期经口进食恶心呕吐的危险因素

目的 分析影响患儿非胃肠道日间手术后早期经口进食恶心呕吐（EOINV）的危险因素。
方法 选择2020年6月至2022年3月全麻下行非胃肠道日间手术、麻醉后进食前未发生恶心呕吐的患儿306例，男206例，女100例，年龄1～12岁，体重5～60 kg，ASA Ⅰ或Ⅱ级。收集患儿性别、年龄、体重、术前禁食禁饮时间、麻醉方式、术中阿片类药、肌松药和肌松拮抗药使用情况、手术类型、手术时间、麻醉时间和术后24 h内EOINV的发生情况。根据EOINV的发生情况将患儿分为两组：EOINV组和无EOINV组，通过单因素与多因素Logistic回归分析患儿EOINV的独立危险因素。
结果 有46例（15.0%）患儿发生EOINV。两组患儿性别、年龄、体重、术前禁食禁饮时间、麻醉方式、肌松药和拮抗药使用情况、手术时间、麻醉时间差异无统计学意义。与无EOINV组比较，EOINV组阿片类药使用率和口内手术比例明显升高（P<0.05）。二元Logistic回归分析结果显示，术中阿片类药使用（OR=3.7，95%CI 1.0～12.5，P=0.048）、口内手术（OR=4.8，95%CI 1.3～16.7，P=0.017）是患儿非胃肠道手术后EOINV的独立危险因素。
结论 术中阿片类药使用、口内手术是患儿非胃肠道日间手术后早期经口进食恶心呕吐的独立危险因素。     

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.     

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.     

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.