淋巴结转移率对胃癌患者预后的评估价值

目的 评估淋巴结转移率(MLR)对胃癌患者预后的预测价值.方法 回顾性分析2005-2009年间在南京医科大学第一附属医院接受根治性切除(pT4期患者除外)并具有完整随访资料的1247例胃癌患者的临床资料,从准确性、均一性和适用性3个方面比较MLR分期和pN分期的预后价值.结果 MLR和pN均与送检淋巴结数目呈正相关(均P<0.01).不同MLR分期及不同pN分期患者5年累计生存率(5-YCSR)的差异均有统计学意义(均P<0.01);进一步经多因素预后分析显示,MLR分期和pN分期均可作为独立的预后因素(均P<0.01).ROC曲线显示,MLR分期预测预后所对应的曲线下面积大于pN分期,但差异并未达到统计学意义(p>0.05).相同MLR组中不同pN组间5-YCSR的差异无统计学意义(P>0.05);而相同pN组中不同MLR组间5-YCSR的差异有统计学意义(P<0.05).同一pN分期患者,送检淋巴结数目不同,其5-YCSR的差异均有统计学意义(P<0.05);而同一MLR分期患者5-YCSR则与送检淋巴结数目无关(P>0.05).结论 MLR是预测胃癌生存的独立预后因素;MLR分期评估胃癌预后的准确性与pN分期相当,但均一性和适用性均优于pN分期.

Abstract：

Objective To evaluate the prognostic value of metastatic lymph node ratio (MLR) for patients with gastric cancer. Methods Data collected from 1247 patients with gastric cancer who underwent radical surgery (pT4 cases were excluded) at the First Affiliated Hospital of Nanjing Medical University between 2005 and 2009 were analyzed retrospectively. MLR was compared to pathological N staging (pN) in terms of prognostic accuracy, homogenicity, and applicability. Results MLR and pN were both positively correlated with the number of retrieved lymph nodes (both P<0.01). Significant differences were found in 5-year cumulative survival rate (5-YCSR) among different pN stages and MLR classification (all P<0.01). Multivariable analysis showed that both pN and MLR were independent prognostic factors (both P<0.01). The area under ROC curve (AUC) of MLR was larger than pN, however the difference was not statistically significant (P>0.05). There were significant differences in 5-YCSR among different MLR stages within the same pN stages (P<0.05), but not among different pN stages within the same MLR stage (P>0.05). Significant differences in 5-YCSR were also found among different retrieved-node groups within the same pN stage (P<0.05), but not within the same MLR stages (P>0.05). Conclusions MLR is an independent prognostic factor for patients with gastric cancer. The prognostic homogenicity and applicability of MLR are better than those of pN, however the prediction accuracy is not favorable.     

淋巴结转移率对淋巴结清扫不足15枚胃癌患者预后评估的价值

目的 评价淋巴结转移率(MLR)对淋巴结清扫不足15枚胃癌患者预后评估的价值.方法 回顾性分析天津医科大学附属肿瘤医院2003年1月到2007年7月间收治的610例胃癌患者的临床资料.其中淋巴结清扫数目不足15枚者320例,15枚以上者290例,比较两组患者在不同病理N分期(pN分期)和不同淋巴结转移度分期(rN分期)中预后的差异.结果 通过Log-rank检验,确定MLR的界值,按此界值可分为rN1(MLR小于或等于10％)、rN2(MLR大于10％,但小于或等于30％)、rN3(MLR大于30％,但小于或等于60％)和rN4(MLR大于60％)4期.对于淋巴结清扫数目不足15枚者,上述不同rN分期患者的生存差异均无统计学意义(均P＞0.05);在同一rN分期中,不同pN分期之间生存差异亦均无统计学意义(均P＞0.05).对于pN2和pN3a期患者,淋巴结清扫数目不足15枚者与15枚以上者的生存差异有统计学意义(均P＜0.05);但在各个rN分期中,两者间差异均无统计学意义(均P＞0.05).多因素预后分析证实,rN分期是淋巴结清扫数目不足15枚胃癌患者的独立预后因素(P=0.012,RR=1.617,95％CI:1.111～2.354).结论 rN分期能很好地对淋巴结清扫不足15枚胃癌患者的预后进行预测.     

淋巴结转移率对食管胃交界部腺癌患者的预后评估价值

目的 比较AJCC/UICC胃癌淋巴结（pN）分期与淋巴结转移率（MLR）分期及以其为基础的TNM与TRM分期系统对食管胃交界部腺癌患者的预后评估价值.方法 回顾性分析天津市肿瘤医院2000年1月至2007年6月间行根治性切除手术的414例食管胃交界部腺癌的临床资料.采用Spearman相关分析检验 pN、MLR与送检淋巴结数3者之间的相关性;应用单因素KaplanMeier生存分析和多因素Cox回归分析检验pN、MLR、TNM及TRM分期与患者预后的关系;通过ROC曲线下面积（AUC）比较它们对患者5年生存率的预测价值.结果 414例患者中位淋巴结清扫数目17（4～71）枚/例,中位转移淋巴结数目4（0～67）枚/例.阳性淋巴结数与淋巴结清扫数目呈正相关 （P＜0.01）,MLR与淋巴结清扫数目无相关性（P＞0.05）.单因素和多因素预后分析结果表明,pN和MLR均可单独作为食管胃交界部腺癌患者的独立预后因素（均P＜0.01）,且MLR的相对危险度（HR）值高于pN（1.573比1.382）;但当pN与MLR共同纳入多因素分析时,MLR仍是独立预后因素（P＜0.01）,而pN不再是其独立预后因素（P＞0.05）.MLR和pN预测患者预后所对应的AUC分别为0.726和 0.714,TRM分期和TNM分期所对应的AUC分别为0.747和0.736,差异均无统计学意义（均P＞0.05）.结论 MLR是食管胃交界部腺癌患者的独立预后因素,MLR及以其为基础的TRM分期对食管胃交界部腺癌患者预后的评估价值或优于pN及以其为基础的TNM分期.     

淋巴结转移率对胃癌患者预后的评估价值

目的 探讨淋巴结转移率（rN）对胃癌根治术患者预后的评估价值.方法 回顾性分析1980-2006年间中国医科大学附属第一医院肿瘤外科收治的接受根治性手术的710例胃癌患者的临床资料.按淋巴结捡取数目将710例患者分为少于15枚组（327例）和15枚以上（含15枚）组（383例）.按淋巴结转移率进行rN分期;按淋巴结转移数量进行pN分期.分别采用Logrank检验和Cox比例风险模型来进行单因素和多因素预后分析.结果 少于15枚组和15枚以上组胃癌患者中位生存时间分别为74个月（95％ CI：55.6～92.4个月）和96个月（95％ CI：77.8～119.2个月）,差异无统计学意义（P＞0.05）.多因素预后分析显示,rN分期既是少于15枚组（P＜0.01,RR=1.225,95％ CI：1.102～1.362）,又是15枚以上组（P＜0.01,RR=1.421,95％ CI：1.269～1.592）胃癌患者的独立预后因素;而pN分期仅仅是少于15枚组胃癌患者的独立预后因素（P＜0.01,RR=1.475,95％ CI：1.168～1.863）.采用rN分期系统,相同分期的两组胃癌患者生存时间的差异均无统计学意义（P＞0.05）;而采用pN分期系统,在pN1期患者中少于15枚组患者生存时间明显短于15枚以上组（P＜0.01）.结论 淋巴结转移率是影响胃癌预后的独立因素.在判断胃癌预后中,按淋巴结转移率的rN分期不受检出淋巴结数目的限制,较pN分期系统更为可靠.     

病理N3期胃癌310例预后分析

目的探讨UICC第7版TNM分期标准中病理N3（pN3）期胃癌患者的预后特征及预后影响因素。方法回顾性分析2000年1月至2006年12月间天津医科大学附属肿瘤医院收治的实施胃癌根治术或扩大根治术的310例pN3期胃癌患者的临床病理和随访资料,分别采用Logrank检验和Cox比例风险模型进行单因素和多因素预后分析。结果310例患者均获随访,随访时间为2～103（平均35．7）月,术后5年生存率为14．6％。其中pN3a期201例,pN3b期109例,5年生存率分别为16．8％和10．3％,差异有统计学意义（P=0．013）。单因素预后分析显示,肿瘤部位、Borrmann分型、pT分期、pN分期、淋巴结转移率及手术方式与患者预后有关（均P〈0．05）。多因素分析显示,浸润深度、手术方式及淋巴结转移率是影响预后的独立危险因素（均P〈0．01）,而pN分期并不是独立的预后影响因素（P=0．658）。按浸润深度对患者进行分层分析显示,对于210例pT4a期患者,pN3a和pN3b亚组5年生存率分别为16．1％和12．8％,差异有统计学意义（P=0．001）;但对于88例pT4b期患者,pN3a和pN,b亚组5年生存率的差异则无统计学意义（8．6％比3．1％,P=0．137）。结论pM期胃癌患者预后较差,肿瘤浸润深度和不同手术方式是影响其预后的重要因素,淋巴结转移率对判断pM期胃癌预后有重要意义。第7版TNM分期中pN3分期能较好反映患者的预后情况。     

癌结节对胃癌患者预后及淋巴结分期的影响及其意义

目的探讨癌结节对胃癌患者预后及淋巴结分期的影响及其意义。方法回顾性分析2016年1至12月河北医科大学第四医院收治907例胃癌患者的临床病理资料, 根据病理诊断将患者分为癌结节阳性组(121例)和癌结节阴性组(786例), 分析癌结节与胃癌患者的临床病理特征及预后的关系。结果本组907例患者中有癌结节121例。单因素分析显示, 癌结节与pT分期、pN分期、pTNM分期、肿瘤直径、神经受侵、脉管受侵均有关(均P<0.05);多因素分析显示, pT分期(P<0.001)、pN分期(P=0.002)、pTNM分期(P=0.001)、肿瘤直径(P=0.033)、神经受侵(P=0.017)、脉管受侵(P=0.011)是癌结节阳性的独立危险因素。癌结节阳性胃癌患者的预后显著差于癌结节阴性患者(χ2=77.869, P<0.001)。单因素分析显示, 年龄、肿瘤位置、肿瘤直径、pT分期、pN分期、pTNM分期、脉管癌栓、神经受侵、有无癌结节及癌结节数量均影响患者预后(均P<0.05)。多因素分析显示, 年龄、pT分期、pN分期、pTNM分期、神经受侵、脉管受侵、癌结节数量是影...     

Ⅲ期胃癌患者的临床病理特征及预后分析

目的 探讨Ⅲ期胃癌(按第7版TNM分期标准)的临床病理特征及影响预后的相关因素.方法 回顾性分析1991年1月至2005年12月间中国医科大学附属第一医院收治的经外科切除治疗的1007例Ⅲ期胃癌患者的临床病理和随访资料.分别采用Log-rank检验和Cox比例风险模型对Ⅲ期胃癌患者的预后进行单因素和多因素分析.结果 1007例Ⅲ期胃癌患者的平均年龄为58.7岁,男女比例为2.6∶1.0;ⅢA期242例,ⅢB期403例,ⅢC期362例.手术接受R0切除者754例(74.9％),R1切除者56例(5.5％),R2切除者197例(19.6％);R0切除者5年生存率为37.8％,高于R１切除者(21.2％)和R2切除者(8.9％),差异有统计学意义(P＜0.05).多因素分析显示,pN分期、pT分期和Borrmann分型是影响R0切除患者预后的独立因素(均P＜0.01).结论 Ⅲ期胃癌患者有其自身的临床病理学特点,治疗上应尽可能施行R0根治术.淋巴结转移数目、肿瘤浸润深度和Borrmann分型是影响接受R0手术的Ⅲ期胃癌患者预后的重要因素.     

Ⅲ期胃癌患者的临床病理特征及预后分析

目的 探讨Ⅲ期胃癌（按第7版TNM分期标准）的临床病理特征及影响预后的相关因素.方法 回顾性分析1991年1月至2005年12月间中国医科大学附属第一医院收治的经外科切除治疗的1007例Ⅲ期胃癌患者的临床病理和随访资料.分别采用Log-rank检验和Cox比例风险模型对Ⅲ期胃癌患者的预后进行单因素和多因素分析.结果 1007例Ⅲ期胃癌患者的平均年龄为58.7岁,男女比例为2.6∶1.0;ⅢA期242例,ⅢB期403例,ⅢC期362例.手术接受R0切除者754例（74.9％）,R1切除者56例（5.5％）,R2切除者197例（19.6％）;R0切除者5年生存率为37.8％,高于R１切除者（21.2％）和R2切除者（8.9％）,差异有统计学意义（P＜0.05）.多因素分析显示,pN分期、pT分期和Borrmann分型是影响R0切除患者预后的独立因素（均P＜0.01）.结论 Ⅲ期胃癌患者有其自身的临床病理学特点,治疗上应尽可能施行R0根治术.淋巴结转移数目、肿瘤浸润深度和Borrmann分型是影响接受R0手术的Ⅲ期胃癌患者预后的重要因素.     

淋巴结转移率对胃癌根治术后患者预后的评估价值

目的评估淋巴结转移率（MLR）分期系统对胃癌根治术后患者预后评估的价值。方法依据MLR分期及第6版、第7版UICC指南N分期这3种分期方法,对1042例胃癌D2根治术后患者进行预后分析。比较3种分期方法预测预后的齐性、相关性和梯度变化曲线,以及受试者工作特征（ROC）曲线下面积（AUC）。结果1042例患者术后5年生存率为47．5％,单因素和多因素预后分析显示,MLR分期（P〈0．01）和第7版N分期（P〈0．05）均为1042例胃癌患者的独立预后因素。MLR分期预测预后的AUC为0．754．高于第6版N分期的0．692和第7版N分期的0．705。与第6版、第7版N分期比较,MLR分期预测预后具有更好的齐性和线性曲线,Akaike信息标准化值更低（7240．017比7364．073和7325．731）。结论MLR分期对胃癌根治术患者的预后预测价值优于UICC指南中的N分期．有望成为一种新的淋巴结分期方法。     

pN0期胸段食管鳞状细胞癌术后复发转移模式分析

目的 分析pN0期胸段食管鳞状细胞癌术后复发转移的相关危险因素.方法 回顾性分析2004年1月至2010年12月连续收治的112例pN0期胸段食管鳞状细胞癌患者临床病理资料.其中男性92例,女性20例;年龄36 ～ 80岁,平均60.3岁.对患者的随访资料进行分析,多因素分析采用Cox比例风险回归模型判定术后3年内复发转移的独立危险因素.结果 术后3年内复发转移率为40.2％(45/112),中位复发转移时间为17.4个月.其中局域性复发38例(33.9％,占复发转移总例数的84.4％),血行转移7例(6.3％).不同肿瘤位置、组织学分化程度、pT分期及病理分期的患者复发转移率差异有统计学意义(x2 =6.380～ 18.837,P＜0.05).多因素分析结果显示,肿瘤位于胸上中段(RR=1.092,P =0.049)和pT3-4a期(RR=3.296,P=0.017)为pN0期胸段食管鳞状细胞癌术后局域性复发转移的独立危险因素.结论 pN0期食管鳞状细胞癌患者术后3年内出现肿瘤复发转移以局域性复发转移最常见.肿瘤位于胸上中段和pT3-4a期是pN0胸段食管鳞状细胞癌术后局域性复发转移的独立危险因素.     

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.     

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.     

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.     

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.     

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.