关节镜手术治疗对早期膝骨关节炎的中期临床疗效

目的：比较关节镜手术治疗与保守治疗对中老年人早期膝关节骨关节炎（early knee osteoarthritis,EKOA）的中期临床疗效,为中老年EKOA的个体化治疗提供临床依据。方法：回顾性纳入2015年1月至2016年12月行关节镜手术治疗或保守治疗的145例（182膝）中老年EKOA患者,其中男35例、女110例,年龄47~79（57.6±6.9）岁,病程6~48（14.6±8.9）个月。根据治疗方式分为关节镜治疗组（47例,58膝）和保守治疗组（98例,124膝）。治疗前患者主要临床症状包括膝关节疼痛、肿胀、交锁、屈伸受限及膝关节无力等,膝关节X线主要表现为关节间隙无狭窄或可疑狭窄、少量骨赘形成,膝关节MRI主要表现为关节软骨和半月板退变或损伤、关节内游离体及滑膜充血水肿等。收集两组患者治疗前的膝关节症状持续时间、半月板是否合并损伤、是否合并关节内游离体、是否存在膝关节交锁等机械性症状,以及治疗前和治疗后的疼痛视觉模拟评分（visual analogue scale,VAS）和Lysholm膝关节功能评分。统计分析组内和组间治疗前后VAS和Lysholm评分差异。结果：两组患者均获随访,时间60~76个月;关节镜手术组患者切口愈合良好,未发生手术并发症。两组间的年龄、性别、身体质量指数（body mass index,BMI）及随访时间差异无统计学意义（P>0.05）。治疗前,关节镜治疗组与保守治疗组相比,关节镜治疗组的症状持续时间更长（P<0.001）,合并半月板损伤（P<0.001）、游离体（P=0.001）及机械性症状（P<0.001）的比例更高,VAS评分（P<0.001）及Lysholm评分（P<0.001）更差。治疗后末次随访时,各组VAS评分、Lysholm评分均较治疗前明显改善（P<0.05）。末次随访时,VAS评分,关节镜治疗组（1.5±1.2）分,保守治疗组（1.6±1.0）分（P=0.549）;Lysholm评分,关节镜治疗组（84.9±12.5）分,保守治疗组（84.2±9.9）分（P=0.676）。结论：对中老年EKOA患者,关节镜手术治疗与保守治疗均具有较满意的中期临床疗效。尽管两组末次随访时疗效差异无统计学意义,但关节镜手术治疗组术前症状较重,多合并半月板损伤或游离体所导致的机械性交锁症状,故对于合并机械性交锁症状或保守治疗效果较差的中老年EKOA患者可考虑关节镜手术治疗。     

羟基红花黄色素A对激素诱导骨髓间充质干细胞成骨分化的影响

目的：观察羟基红花黄色素A（HSYA）对激素诱导兔骨髓间充质干细胞（BMSCs）内成骨标志物碱性磷酸酶、Cbfαl及Ⅰ型胶原表达的影响,探讨其防治激素性股骨头缺血性坏死的作用机制。方法：健康成年新西兰大白兔15只,体重0.9～1.3 kg,腹腔注射麻醉后,无菌条件下作胫骨和髂前上棘骨髓腔穿刺抽取骨髓血,分离出BMSCs,体外培养并传代,取第3代生长状态良好的BMSCs随机分为空白组,模型组及羟基红花黄色素A低、中、高剂量组。模型组用大剂量地塞米松诱导BMSCs成脂分化,抑制其成骨分化;羟基红花黄色素A低、中、高剂量组加入地塞米松作用的同时给予羟基红花黄色素A干预;空白组无特殊处理。1周后检测各组细胞内成骨标志物碱性磷酸酶活性、Cbfαl及Ⅰ型胶原 mRNA的表达。结果：模型组兔BMSCs内碱性磷酸酶活性较空白组明显下降（P<0.01）,Cbfαl及Ⅰ型胶原 mRNA的表达也明显降低（P<0.01）,而HSYA各组较模型组均有明显升高（P<0.05或P<0.01）.结论：羟基红花黄色素A治疗激素性股骨头缺血坏死的机制可能与对抗激素诱导下的BMSCs成骨分化减少有关。     

个体化设置股骨开髓点与外翻角在股骨外弓患者人工全膝关节置换术中的应用

目的：探讨外移股骨开髓点并设置个性化股骨外翻角能否改善合并股骨外弓的人工全膝关节置换术（total knee arthroplasty,TKA）患者下肢力线。方法：2016年3月至2018年10月,收治50例（55膝）合并股骨外弓拟行TKA的膝内翻畸形的骨关节炎患者。男10例,女40例;年龄63.1~80.5（67.8±5.8）岁。单侧45例,双侧5例。55膝的骨关节炎分期均为Kellgren-Lawrence分级Ⅲ-Ⅳ级,病程2~10年。术前特种外科医院（Hospital for Special Surgery,HSS）评分疼痛（15.20±3.52）分,功能（8.30±2.96）分,活动度（10.15±2.85）分,肌力（4.20±1.95）分,屈曲畸形（5.50±3.05）分,稳定性（6.15±2.20）分,总分（47.93±3.39）分。股骨外弓角6.4~16.7（10.63±2.29）°,胫股角7.4~12.6（12.04±3.59）°,解剖股骨远端外侧角83.10~91.20（84.55±1.66）°,膝关节中心至下肢力线距离2.01~6.00（3.57±1.12） cm。置换术中均通过个性化设置股骨开髓点与外翻角,获得良好下肢力线。结果：术前股骨开髓点外移距离0.24~0.74（0.54±0.10） cm,股骨内外髁间距离6.86~8.12（7.27±0.27） cm。术前股骨外翻角（valgus correction angle,VCA）7.20~13.80（9.38±1.38）°;矫正后VCA''6.10~9.50（7.36±0.82）°。50例患者均获随访,时间3~36（13.5±5.8）个月。术后患者均获得良好的膝关节功能,术后3个月HSS评分疼痛（25.30±3.05）分,功能（18.25±2.05）分,活动度（16.05±0.75）分,肌力（6.20±2.10）分,屈曲畸形（8.80±1.85）分,稳定性（8.20±1.75）分,总分90.00~93.00（91.82±0.98）分,总分较术前提高（t=1.728,P=0.038）。术后X线片复查示,假体没有松动、下沉及骨溶解等征象发生;术后第2天负重位X线片上胫股角1.30~4.90（2.53±0.83）°,解剖股骨远端外侧角87.50~91.30（88.73±0.86）°,膝关节中心至下肢力线距离0.02~1.20（0.23±0.05） cm,均较术前改善（t=2.415,P=0.019;t=1.496,P=0.041;t=1.912,P=0.033）。结论：合并股骨外弓的TKA中通过外移股骨开髓点并设置个性化股骨外翻角能获得良好的下肢力线和膝关节功能。     

基于Caprini风险评估模型的干预策略对全膝关节置换术后静脉血栓栓塞症的预防效果观察

目的：探讨基于Caprini血栓风险评估模型的干预策略对全膝关节置换术（total knee replacement,TKA）后静脉血栓栓塞症（venous thromboembolism,VTE）的预防效果。方法：自2017年5月至2021年12月收治257例TKA患者,以2019年5月是否引进Caprini血栓风险评估模型为界分为传统常规干预策略（对照组121例）和基于Caprini血栓风险评估模型的干预策略（观察组136例）。对照组男79例,女42例;年龄50~78（63.10±11.86）岁;体质量指数（body mass index,BMI）19~32（25.21±4.95） kg/m²;左侧55例,右侧66例。观察组男81例,女55例;年龄50~78（64.35±10.54）岁;BMI 19~32（24.43±5.18） kg/m²;左侧87例,右侧49例。比较两组患者术后VTE发生率,疼痛视觉模拟评分（visual analogue scale,VAS）,美国特种外科医院（Hospital for Special Surgery,HSS）膝关节评分,患肢肿胀情况,血流平均速度（mean velocity,Vm）,峰值速度（peak velocity,PV）,D-二聚体（D-dimer,D-D）及凝血酶原时间（prothrombin time,PT）和并发症发生率。结果：观察组VTE发生率为1.47%（2/136）,对照组VTE发生率为9.09%（11/121）,两组比较差异有统计意义（χ²=6.976,P=0.008）。术后7 d,观察组VAS、HSS评分及患肢周径差值均明显优于对照组（P<0.05）。术后7 d,两组血流Vm和PV水平均明显升高（P<0.001）,且观察组血流Vm、PV水平高于对照组（P<0.001）。术后7 d,观察组血清D-D水平明显低于对照组,PT水平明显高于对照组（P<0.05）。两组并发症发生率比较,差异有统计意义（χ²=4.488,P=0.034）。结论：基于Caprini血栓风险评估模型的干预策略可有效降低TKA患者VTE发生率及并发症发生率,改善患肢肿胀、血流动力学及凝血功能状态,有助于膝关节功能恢复。     

影响症状性外侧盘状半月板术后疗效的相关危险因素分析

目的：探讨关节镜治疗症状性外侧盘状半月板（discoid lateral meniscus,DLM）术后疗效的影响因素。方法：回顾性分析2008年9月至2015年9月于四川大学华西医院运动医学中心诊断为症状性DLM并行关节镜手术治疗的患者。膝关节功能由Lysholm评分系统进行评估,根据评分结果分为优（≥ 90分）、良（80~89分）、可（70~79分）、差（<70分）。收集患者临床资料,包括性别、手术年龄、体质量指数、工作强度、症状持续时间、膝关节创伤史、受累膝关节侧别、DLM分型、DLM损伤类型、DLM损伤部位、内侧半月板损伤、膝关节软骨损伤部位及损伤程度、Kellgren-Lawrence （K-L）分级、手术方式、末次随访时间共16项拟研究因素。根据数据类型,单因素分析采用Kruskall-Wallis秩和检验或χ²检验,多因素分析采用有序Logistic回归模型。单因素分析具有统计学意义的因素纳入多因素分析模型,最终获得影响症状性DLM术后疗效的独立危险因素。结果：根据纳入排除标准,共纳入502例患者。末次随访的Lysholm功能分级高于术前（P<0.001）。单因素分析显示：在Lysholm各功能分级之间,性别、体质量指数、工作强度、膝关节创伤史、手术年龄、症状持续时间、内侧半月板损伤、K-L分级、手术方式、膝关节软骨损伤部位及程度的差异均有统计学意义（P<0.05）。有序Logistic回归分析显示：女性是影响术后疗效的独立危险因素（P=0.002,OR=0.370）;体质量指数（P=0.007,OR=0.894）,工作强度（P=0.004,OR=0.525）,手术年龄（P<0.001,OR=0.953）,症状持续时间（P<0.001,OR=0.989）,膝关节软骨损伤程度（P=0.016,OR=0.631）与Lysholm膝关节功能分级呈负相关。结论：关节镜是治疗症状性DLM安全、有效的方法,性别、体质量指数、工作强度、手术年龄、症状持续时间以及膝关节软骨损伤程度是症状性DLM术后疗效的独立影响因素。     

改良锚钉置入角度和应用双滑轮技术治疗髌骨下极撕脱骨折

目的:评价改良锚钉置入角度和应用双滑轮技术治疗髌骨下极撕脱性骨折的临床疗效。方法：回顾性分析2015年12月至2018年12月收治的髌骨下极撕脱性骨折患者22例,男10例,女12例;年龄19~70（44.00±15.24）岁。均采用改良锚钉置入角度和应用双滑轮技术治疗。术后定期随访,采用膝关节活动度（range of motion,ROM）和Bostman评分系统评价膝关节功能康复情况。结果：22例全部获得随访,时间18~46（30.86±8.00）周。末次随访时,患侧膝关节ROM为（130.82±4.69）°,健侧膝关节ROM为（133.23±3.15）°,差异无统计学意义（P>0.05）。末次随访Bostman评分（28.45±1.41）分,优18例,良4例。结论：改良锚钉置入角度和应用双滑轮技术治疗髌骨下极撕脱性骨折操作简便,疗效满意,膝关节功能恢复良好。     

超声评估椎动脉起始段纡曲

目的 观察超声评估椎动脉起始段（VAO）纡曲的价值。方法 纳入37例于颈内静脉置管前接受颈部血管超声检查的结直肠肿瘤患者,并根据VAO纡曲角度将其分为≤90°组（n=10）及>90°组（n=27）。比较2组患者一般资料,包括性别、年龄及体质量指数（BMI）,以及超声特征,包括VAO纡曲角度及活动度等;分析超声评估VAO纡曲的价值。结果 ≤90°组与>90°组患者性别、BMI及右侧VAO活动度差异均无统计学意义（P均>0.05）,而≤90°组患者年龄及左侧VAO活动度均大于>90°组（P均<0.05）。平静呼吸及深吸气末时,2组患者左侧VAO纡曲角度均小于右侧（P均<0.05）;且平静呼吸状态时,左侧VAO纡曲角度小于深吸气末（P<0.05）。结论 超声对评估VAO纡曲角度及其在呼吸运动下的变化具有一定价值。     

铁蓄积骨质疏松模型凝血状态及微血栓和血管密度变化的研究

目的：了解铁蓄积骨质疏松模型中凝血状态、微血栓、微血管床及骨密度的变化,探讨骨质疏松范畴铁蓄积对凝血功能、血管方面的影响。方法：选取健康24只6月龄雄性SPF级SD大鼠,体重（250±20）g,随机分为对照组和铁蓄积组,每组12只。铁蓄积组用枸橼酸铁（ferric ammonium citrate,FAC）90 mg/kg腹腔注射干预,对照组采用等体积生理盐水腹腔注射,每周2次,干预9周。干预完成后,检测两组血清铁蛋白、凝血功能、微血栓、血管密度及股骨远端骨小梁三维形态重建和空间结构参数,并进行统计学分析。结果：铁蓄积组血清铁蛋白（136.36±35.41）μg/L较对照组（68.44±16.86）μg/L显著升高,铁蓄积组骨密度（0.167±0.024）g/cm³较对照组（0.400±0.030）g/cm³显著下降;铁蓄积组的纤维蛋白原（2.03±0.13）g/L较对照组（1.78±0.46）g/L明显升高,D-二聚体含量（534.95±31.81）ng/ml较对照组（329.02±84.99）ng/ml明显增高（P<0.05）,而凝血酶时间（39.64±2.18）s和凝血酶原时间（8.70±0.39）s较对照组（44.92±2.98）s、（9.44±0.49）s明显缩短（P<0.05）;墨汁染色后,铁蓄积组的微血管密度（17.46±2.07）%较对照组（23.81±2.98）%明显缩小（P<0.05）。HE和MSB染色均显示铁蓄积大鼠骨髓中存在微血栓,同时在心肌中也存在微血栓。结论：在铁蓄积影响的骨质疏松模型中,铁蓄积对凝血功能有显著影响,血液相对呈高凝状态,骨血管床减少,骨髓中有微血栓存在,血液的高凝状态及微血栓的形成可能是铁蓄积骨质疏松症发生的重要影响因素。     

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.