4437例瓣膜置换术住院死亡危险因素分析及安贞风险评分系统建立

目的 对4437例心脏瓣膜置换于术病人进行同顺性研究,定量评估住院死亡的危险因素,建立瓣膜置换手术住院死亡风险模型,以及安贞医院瓣膜置换手术风险评分系统.方法 选取安贞医院心脏外科数据库中收录的主动脉瓣置换术病人848例,二尖瓣置换术病人2202例,主动脉瓣、二尖瓣舣瓣膜置换术病人1387例.选取术前.术中33个临床指标作为住院死亡的可能影响因素,利用单因素分析进行筛选,然后利用多因素分析确立3种手术的住院死亡危险因素并建立风险模型.结果经多因素分析,年龄、体表面积、心功能分级、术前肌酐和体外循环时间是主动脉瓣置换术住院死亡的危险因素.心功能分级、术前心衰史、心胸比率、短轴缩短率、病因、左心室收缩末径,体外循环时间和术中1ABP是二尖瓣置换术住院死亡的危险因素.年龄、心功能分级、术前心内膜炎、糖尿病史、既往二尖瓣球囊扩张术,体重指数和体外循环时间是丰动脉瓣、二尖瓣双瓣膜置换术的住院死亡危险因素.ROC曲线下面积分别为主动脉瓣置换术模型0.921(95%CI,0.874～0.967),二尖瓣置换术模型0.859(95%C1,0.813～0.905),主动脉瓣、二尖瓣舣瓣膜置换术模型0.868(95%CI,0.827～0.908).Hosmer-Leme-show检验显示,主动脉瓣置换术模型χ~2=1.463,P=0.993,二尖瓣置换术模型χ~2=8.720,P=0.366,主动脉瓣、二尖瓣双瓣膜置换术模型χ~2=8.134,P=0.420,预计病死率与实际观测病死率差异无统计学意义.结论 3个模型能够定定量评估瓣膜置换术病人住院死亡风险.     

全髋关节置换术患者延迟出院的危险因素分析

目的分析全髋关节置换术患者延迟出院的危险因素。方法回顾性分析2015年1月至2018年7月择期行单侧全髋关节置换术患者的临床资料,包括性别、年龄、BMI、ASA分级、手术时间、麻醉方式、术中失血量、术中输液量、术中阿片类药物用量、术中血管活性药物用量、PACU停留时间、术后随访静息疼痛评分、术前住院时间、术前合并症、术后并发症及转归情况。根据术后住院时间将患者分为两组:正常出院组(术后住院时间≤14 d)和延迟出院组(术后住院时间>14 d),采用单因素和多因素Logistic回归分析影响延迟出院的因素。结果共纳入908例患者。单因素分析显示,与正常出院组比较,延迟出院组的年龄明显偏高,术中失血量明显增多,手术时间、PACU停留时间、术前住院时间明显延长,术前合并症、术后并发症明显增多(P<0.05)。Logistic回归分析显示,年龄≥70岁(OR=2.075,95%CI 1.287~3.346,P=0.003)、手术时间>3 h(OR=1.997,95%CI 1.181~3.375,P=0.010)、术中失血量≥800 ml(OR=2.898,95%CI 1.449~5.794,P=0.003)、PACU时间>60 min(OR=1.745,95%CI 1.064~2.859,P=0.027)、术前住院时间≥7 d(OR=1.805,95%CI 1.114~2.924,P=0.016)、术前有合并症≥2个(OR=2.912,95%CI 1.513~5.825,P=0.003)是导致患者延迟出院的独立危险因素。结论患者年龄、术中失血量、手术时间、PACU停留时间、术前住院时间及术前合并症是全髋关节置换术后出院延迟的独立危险因素,针对危险因素进行有效干预是缩短住院时间改善患者预后的重要策略。     

老年冠心病患者行骨科手术围术期心脏事件的危险因素

目的 筛选老年冠心病患者行骨科手术围术期主要心脏事件(MACEs)的危险因素.方法 选择行择期中危或高危骨科手术的冠心病患者129例,年龄≥65岁,性别不限.根据术中及术后30 d内是否发生MACEs,将患者分为MACEs组和非MACEs组.记录患者年龄、性别、冠状动脉重建史、心肌梗死史、心力衰竭史、心绞痛史、全身血管病史、脑血管病史、糖尿病史、基础血压、术前血压、术前血常规、肌酐、血糖、心电图、超声心动图、ASA分级、术中输血、手术及麻醉时间、术后是否返ICU及术后引流量.将组间差异有统计学意义的因素进行多因素logistic回归分析,筛选该人群围术期MACEs的危险因素.结果 21例患者发生围术期MACEs,发生率为16.3%.logistic回归分析结果显示:半年内不稳定型心绞痛史、术前红细胞压积≤35%、术前心电图示心律失常及室壁运动异常为老年冠心病患者行骨科手术围术期MACEs的危险因素(P＜0.05),其危险指数分别为5、3、3、4.结论 半年内不稳定型心绞痛史、术前红细胞压积≤35%、术前心电图示心律失常及室壁运动异常是老年冠心病患者行骨科手术围术期MACEs的危险因素.     

婴幼儿复杂先天性心脏病术后机械通气时间延长的危险因素分析

目的探讨婴幼儿复杂先天性心脏病术后机械通气时间延长(prolonged mechanical ventilation,PMV)的危险因素。方法回顾性分析2016年1月至2017年12月北京安贞医院小儿心外科收治的150例复杂先天性心脏病患儿,男80例,女70例,年龄≤6个月,RACHS-1分级≥3级。收集患儿一般资料、相关病史、手术类型、术前合并症及治疗情况、术中心肺转流(cardiopulmonary bypass, CPB)时间、深低温及血气指标;术后延迟关胸、放置起搏器情况;术后24 h内最低OI、最高正性肌力药剂量评分值(VIS评分)、拔管失败及术后并发症情况。采用Logistic回归模型分析婴幼儿复杂先天性心脏病术后PMV的危险因素。结果 42例(28%)患儿存在术后PMV。单因素分析显示,年龄、体重、RACHS-1分级、既往紫绀、既往肺炎、急诊手术、术前机械通气支持、术前射血分数(ejection fraction, EF)、深低温、CPB时间132 min、术中最低pH、术中最高血糖浓度高、术中最高乳酸浓度高、延迟关胸、应用起搏器、术后24 h内最高VIS评分和最低OI及术后并发症是婴幼儿复杂先天性心脏病术后PMV的危险因素(P0.05)。多因素Logistic回归分析显示,CPB时间132 min(OR=11.04,95%CI 2.07～58.96,P=0.005),术中最高乳酸浓度过高(OR=1.53,95%CI 1.07～2.20,P=0.021)和拔管失败(OR=17.28,95%CI 2.46～121.20,P=0.004)是婴幼儿复杂先天性心脏病术后PMV的独立危险因素。结论 CPB时间132 min、术中最高乳酸浓度过高和拔管失败可作为预测婴幼儿复杂先天性心脏病术后PMV的危险因素。     

主动脉瓣置换术1026例分析

目的 探讨主动脉瓣置换患者的病因及影响预后的因素.方法 1980年12月至2006年12月接受主动脉瓣置换术的患者1026例,分析患者术前情况及手术方式对预后的影响.结果 手术病死率4.3%,主要死亡原因有心力衰竭、多器官功能衰竭和心内膜炎.术后早期主要并发症发生率为10.6%.术前左心室射血分数≤40%、心内膜炎、主动脉瓣关闭不全和急诊手术是术后死亡的危险因素.随访率为92.3%,总随访时间6125.6人年,平均随访6.3年(8个月-26年).晚期病死率为0.54%人年(3.4%),死亡原因以心力衰竭、心内膜炎和心律失常多见.再手术率为0.22%人年(1.4%),再次手术的主要原因为人工瓣膜心内膜炎和瓣周漏.结论 随着人口的老龄化,退行性主动脉瓣病变发生率逐年升高.正确掌握手术时机,妥善处理心内膜炎,避免人工瓣膜不匹配和加强后续治疗及随访有助于改善预后.     

三尖瓣置换术围术期及中长期临床效果分析

目的 评价三尖瓣置换术围术期及中长期疗效,并比较在三尖瓣位置生物瓣和机械瓣置换的相对优缺点和适应证,以提高该类手术的疗效. 方法 回顾性分析1992年4月至2008年2月收治的128例行三尖瓣置换术患者的围术期疗效及中长期随访结果 ,并按首次三尖瓣置换所采用的瓣膜种类不同分为机械瓣组(89例)和生物瓣组(39例).采用Kaplan-Meier曲线计算该类患者的中长期生存率和中长期人工瓣膜相关事件(包括血栓栓塞和人工瓣膜血栓形成、抗凝相关性出血、人工瓣膜毁损事件)的发生率.用 Binary logistic回归对三尖瓣置换患者早期、晚期死亡的危险因素进行多因素分析. 结果 围术期死亡19例(14.84%).随访103例(94.5%),6例失访,随访时间4.93±2.92年,随访期间死亡11例(10.7%).生物瓣组10年生存率为65.6%±17.4%,机械瓣组为68.7%±10.8%(Log-rank 检验, χ2=0.74,P=0.390).生物瓣组5年无血栓栓塞事件率为92.3%±7.4%,机械瓣组为87.1%±4.6%(Log-rank 检验,χ2=0.962,P=0.327).生物瓣组和机械瓣组10年无出血事件发生率分别为100%和79.7%±9.7%(Log-rank检验, χ2=1.483,P=0.223).9例患者行再次三尖瓣置换术,生物瓣组7年无再次手术率为71.1%±18.0%,机械瓣组10年无再次手术率为78.8%±10.2%(Log-rank检验, χ2=2.76,P=0.096).Binary logistic多因素分析结果 显示:三尖瓣置换术前有心脏手术史、腹水是早期死亡的危险因素,而术前有腹水、术前心功能分级(NYHA)Ⅲ/Ⅳ级、置换多个瓣膜为晚期死亡的危险因素. 结论 对重度三尖瓣反流,应该较早或较积极地施行三尖瓣手术,以防止右心功能进行性衰竭,而影响三尖瓣置换术的近期及中长期生存率和生活质量.在三尖瓣置换术中,机械瓣和生物瓣有相似的中长期效果.     

成人体外循环心脏手术后急性肾损伤的危险因素分析

目的 探讨成人体外循环心脏手术后急性肾损伤(AKI)的发病情况及危险因素.方法 回顾性分析2006年9月至2011年7月行体外循环心脏手术的成人患者6665例.根据术后是否发生AKI分为两组,AKI组1779例,非AKI组4886例.收集患者临床资料,采用单因素和多因素Logistic回归分析AKI发生的危险因素.结果 AKI组中102例(1.53％)进行了肾脏替代治疗(RRT),院内死亡44例;非AKI组死亡14例,AKI组住院病死率显著高于非AKI组患者(2.47％对0.29％,P＜0.01).多因素Logistic回归分析显示,男性、年龄(每增加10岁)、高血压史、糖尿病史、术前基础血肌酐值≥115μmol/L、术前血尿酸值≥420 μmol/L、术前左心室射血分数＜0.40、术前贫血、手术类型(主动脉瘤手术)、体外循环≥120 min、深低温停循环的应用、术后低血压、术后24 h内输血量≥1000 ml、术后机械通气≥72 h是体外循环心脏术后发生AKI的独立危险因素.结论 AKI是成人体外循环心脏手术后的常见并发症,与术后病死率的增加有关.AKI的发生与多种围手术期危险因素有关,应充分重视这些危险因素的评估和预防.     

骨科常见手术术后谵妄的危险因素分析

 目的 分析骨科常见手术术后发生谵妄的相关危险因素。方法 回顾性分析2011年1月至2013年12月行股骨转子间骨折内固定术（155例）、人工股骨头置换术（64例）、全髋关节置换术（169例）、膝关节置换术（65例）和肩关节周围手术（72例）患者525例,根据是否发生术后谵妄分为谵妄组（56例）和非谵妄组（469例）。记录谵妄组和非谵妄组患者年龄、性别、血型以及住院天数、手术方式、麻醉方式、术前准备时间、术前基础疾病状况、术前及术后白蛋白、术前及术后血红蛋白水平、术后电解质是否紊乱、术中出血量、手术持续时间、术后是否ICU监护和输血量等围手术期因素共17项。采用单因素和多因素Logistic回归分析术后发生谵妄的相关危险因素。结果 单因素Logistic回归分析结果显示,可能与术后谵妄相关的因素有年龄、手术方式、术前准备时间、术前白蛋白水平、术前血红蛋白水平、术后电解质是否紊乱、手术持续时间、是否术后ICU监护和输血量等9项。多因素Logistic回归分析显示：年龄70~80岁和>80岁组术后谵妄发生率高于年龄<70岁组,OR值分别为12.998（95%CI：2.829,59.713）和36.210（95%CI：8.222,159.476）;术前准备时间4~6 d组术后谵妄发生率高于术前准备时间≥7 d组,OR值为3.903（95%CI：1.658,9.188）;术后电解质紊乱组术后谵妄的发生率高于电解质正常组,OR值为2.160（95%CI：1.065,4.382）。结论 高龄、术前准备时间不充分和术后电解质紊乱是骨科术后发生谵妄的高危因素。     

肝移植患者术后气管导管延迟拔管的危险因素

目的 探讨行肝移植手术患者术后气管导管延迟拔管的危险因素。方法 回顾性分析2018年1月至2021年10月于全麻下行肝移植手术患者339例,男264例,女75例,年龄18～80岁,BMI 14～35 kg/m²,ASAⅡ—Ⅴ级。根据术后24 h内是否拔除气管导管分为两组：正常拔管组和延迟拔管组。采用单因素分析延迟拔管相关的影响因素,多因素Logistic回归分析筛选肝移植术后延迟拔管的独立危险因素。结果 有60例(17.7%)患者术后延迟拔管。与正常拔管组比较,延迟拔管组终末期肝病模型(MELD)评分明显升高(P<0.05),手术时间、冷缺血时间明显延长(P<0.05),术中严重低血压发生率明显升高(P<0.05),术中6%羟乙基淀粉输入量、浓缩红细胞输入量、血浆输入量明显增多,(P<0.05)。多因素Logistic回归分析显示,MELD评分≥17分(OR=1.829,95%CI 1.004～3.333,P=0.049)、浓缩红细胞输入量>4 U(OR=3.264,95%CI 1.650～7.271,P=0.001)和冷缺血时间≥4...     

肝内胆管结石手术切口感染危险因素分析

目的：分析肝内胆管结石术后切口感染的危险因素,为降低术后切口感染发生率提供有效预防措施。 方法：回顾性分析2005年7月—2012年12月间手术117例治疗肝内胆管结石患者临床资料,根据患者是否接受预防切口感染的特殊围手术期处理分为特殊处理组与常规处理组,比较两组患者术后切口感染发生率及其他临床指标;再根据患者是否发生切口感染将患者分为感染组与非感染组,分析引起切口感染的危险因素。 结果：与常规处理组比较,特殊处理组术后切口感染发生率明显降低（14.6% vs. 36.8%）,引流管拔除时间、抗生素使用时间、术后住院时间明显缩短、住院费用明显减少（均P<0.05）。单因素分析显示,术后切口感染与年龄、合并糖尿病、术前胆管炎、既往胆道手术史、胆汁培养阳性、术中采取预防措施、手术时间、拔除引流管时间有关（均P<0.05）;多因素分析显示,合并糖尿病、既往胆道手术史和延迟拔除引流管是术后切口感染的危险因素,而术中采取预防措施是保护性因素（均P<0.05）。 结论：合并糖尿病、既往胆道手术史和术后延迟拔除引流管是术后切口感染的独立危险因素,而术中采取预防措施可降低肝内胆管结石患者术后切口感染发生率,且有利于患者快速康复。

     

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.