胃肠道恶性肿瘤根治术后腹腔化疗的方法

目的　探讨胃肠道的恶性肿瘤根治术后腹腔化疗方法及其相关副作用。方法　应用直接注入法、腹腔置管法、腹腔置泵法三种手段进行腹腔化疗 ,选用的药物是 :5 Fu、CF、HCPT、PDD、VP 16等联合化疗药物组合有三种 :(1) 5 Fu、CF、HCPT ;(2 ) 5 Fu、CF、PDD ;(3) 5 Fu、CF、VP 16。化疗剂量与每一静脉化疗周期量相同 ,即 :5 +Fu 2 .5～ 3.0 g/周期 ;CF 10 0～ 15 0mg/天 (使用 5 Fu当天前 2～ 4小时应用 ) ;HCPT 40～ 5 0mg/周期 ;PDD 10 0mg/周期 ;VP 16 30 0～ 5 0 0mg/周期 ;输入腹腔的液体量在 2 5 0 0～ 30 0 0ml。结果　三种腹腔化疗方法各有优缺点 ,以腹腔置管法应用最为常用 ,腹腔化疗方法本身引起的主要副作用是腹胀 (10 0 % )、腹痛 (14.9% )、肠损伤、肠麻痹、腹膜炎偶有发生 ;腹腔化疗药物引起的反应有恶心、呕吐、白细胞下降、肝功损伤、腹泻、脱发等 ,但程度不重。结论　直接注入法、腹腔置管法、腹腔置泵法是值得推广的腹腔化疗方法。     

代谢综合征与原发性IgA肾病蛋白尿的相关性研究

目的:统计代谢综合征(metabolic syndrome,MS)在原发性Ig A肾病(Ig A nephropathy,Ig AN)患者中的发生率;探讨Ig AN合并MS患者的临床特点以及MS与Ig AN蛋白尿的相关性。方法:回顾性分析了2018年01月～2018年12月杭州市中医院行肾组织活检确诊为原发性Ig AN的317例患者的临床资料,统计MS的发生率,对比MS组与非MS组间的临床资料,采用Logistic回归分析确定蛋白尿的危险因素。结果:317例原发性Ig AN患者中,MS发生率为24. 61%,MS组患者的24 h尿蛋白定量、血尿酸(UA)、血肌酐(Scr)、尿素氮(BUN)显著高于非MS组,肾小球滤过率(e GFR)明显低于非MS组(均P 0. 05)。根据蛋白尿水平分组,发生大量蛋白尿组MS比例(40. 91%)明显高于少量蛋白尿组(15. 25%)和中等量蛋白尿组(35. 59%)(P 0. 05)。MS及各组分与Ig AN患者发生中等量以上蛋白尿(≥1. 0 g/d)密切相关,校正后的多元Logistic回归分析结果显示:餐后血糖(PBG)、血压、三酰甘油高密度脂蛋白比值(TG/HDL-C)升高是大量蛋白尿的独立危险因素。结论:原发性Ig AN患者中MS发生率为24. 61%,MS及其组分与蛋白尿密切相关。其中以餐后血糖、血压、血脂影响最为显著。     

HOE 077对胰岛细胞微囊外纤维化反应及其活力的影响

目的　研究抗肝纤维化药物HOE 0 77对胰岛微囊外纤维化反应及细胞活力的影响。方法　猪胰岛分离后包裹在海藻酸钡微囊内 ,移植于Balb/c小鼠肝内。术后HOE 0 77通过溶解于饮用水中给药 ,对照组饮水中不含HOE 0 77。 1个月后处死动物 ,病理检查观察包囊外的纤维化反应程度 ,评价囊内细胞的存活情况。结果　对照组显示了明显的纤维化反应 ,纤维包裹层厚度平均为(6 2 .12± 3.84) μm ,细胞活力为 (15 .16± 2 .32 ) % ;而HOE 0 77治疗组纤维包裹厚度为 (4 1.44±2 .45 ) μm ,活力为 (2 3 .0 8± 2 .45 ) %。统计学分析表明 ,两组在囊外纤维包裹层的厚度及细胞活力上差异均有显著性 (P <0 .0 0 0 1和P <0 .0 1)。结论　抗肝纤维化药物HOE 0 77的应用为减轻微包囊的纤维化反应提供了一个新的途径     

AN04-2治疗骨质疏松的成药性评价

目的考察AN04-2对骨质疏松的治疗作用和安全性,对其成药性进行评价。方法人成骨细胞hFOB1.19加入不同浓度的AN04-2处理7 d,检测碱性磷酸酶(ALP)的表达;野生型AB品系斑马鱼,以泼尼松诱导建立骨质疏松症模型,分别注射给予不同剂量的AN04-2处理,测定斑马鱼脊椎骨荧光强度;雌性SD大鼠行双侧卵巢切除手术(OVX),建立大鼠骨质疏松模型,给予不同剂量的AN04-2治疗12周,测量腰椎L5及右股骨的骨密度;SD大鼠单次静脉注射给予生理盐水及不同剂量的AN04-2,观察动物的急性毒性反应。结果0.3~10μmol/L浓度的AN04-2可显著促进人成骨细胞HFOB1.1的ALP的表达;剂量为15、50 ng/尾的AN04-2治疗可显著增加斑马鱼脊椎骨荧光强度(P<0.001);1周1次皮下注射不同剂量的AN04-2,OVX大鼠的第五腰椎和右股骨的BMD有升高的趋势,但差异无统计学意义(P>0.05)。大鼠单次静脉注射AN04-2高至100 mg/kg,未见明显不良反应。结论AN04-2体内外对骨质疏松均有一定的治疗作用,且安全性良好,具有较好的成药性。     

氟尿嘧啶类药物在结、直肠癌术后化疗中副反应的比较

目的 比较5-FU、氟铁龙、希罗达3种氟尿嘧啶类药物在结、直肠癌术后化疗中的副反应。方法 64例结肠、直肠癌术后病例分成3组:分别采用静脉滴注5-FU/CF、口服氟铁龙/CF和口服希罗达方案。观察3组病例在化疗过程中出现的副反应及其程度。结果 5-FU/CF组副反应主要为骨髓抑制(34.6％)、恶心(23％)、呕吐(11.5％)。氟铁龙/CF组副反应主要为腹泻(55％)、口炎(25％)和手足综合征(10％)。希罗达组副反应主要为腹泻(28％)、手足综合征(38.9％)和口炎(16.6％)。结论 3种化疗方案均可导致不同程度的副反应,尤其是氟铁龙/CF方案的胃肠道反应发生率高,且程度较重。     

阴茎、手掌和足底交感皮肤反应的比较研究

目的 比较研究健康人及阴茎勃起障碍(ED)病人阴茎、手掌和足底交感皮肤反应(SSR)潜伏期和波幅。方法 对25例健康人和59例ED病人采用电流刺激正中神经,金属盘状表面电极同时在阴茎体部、手掌和足底皮肤表面记录阴茎(PSSR)、手掌(HSSR)和足底交感皮肤反应(FSSR)。结果 正常组阴茎、手掌和足底SSR的潜伏期(PLP0、HLP0和FLP0)分别为(134286)ms、(129191)ms和(2055268)ms。病人组PLP0、HLP0和FLP0分别为(1790370)ms(P<0.01)、(1329106)ms(P>0.05)和(2095281)ms(P>0.05)。正常组阴茎、手掌和足底SSR的AN1波幅(PAN1、HAN1和FAN1)分别为(994441)μv、(1129589)μv和(1083412)μv。病人组PAN1、HAN1和FAN1分别为(442372)μv(P<0.01)、(1238438)μv(P>0.05)和(1015499)μv(P>0.05)。结论 阴茎交感皮肤反应潜伏期和波幅及其与手掌或足底交感皮肤反应的相应比值可以用来评价阴茎自主神经结构与功能状况。     

开放性创面局部高营养疗法

深部烧伤和大的外伤性软组织缺损经清创术除去坏死和损伤组织后,如果肉芽创面大,超过患区的恢复功能时,则肉芽生长缓慢,创面容易感染。近年来对这类开放性创面采用局部高营养疗法,即用经氨基酸/维生素浸湿的纤维海绵覆盖创面。可促使肉芽组织生长进一步改善。此项治疗的具体操作措施如下:在创面上覆盖数层纤维海绵,逐层缓慢注入下列一种液体将其浸湿;(1)0.9%NaGl,(2)10%葡萄糖,(3)右旋糖酐水解于0.9%NaCl液中。(4)7%Levamin(在5%山梨醇中含必需氨基酸和甘氨酸的合剂),(5)含有氨基酸(Le-7402.A)和葡萄糖,     

妇科腹腔镜手术并发症原因及其防治的探讨

目的　探讨腹腔镜手术并发症的原因及其防治措施。　方法　回顾分析从 1995年 1月至 2 0 0 2年 3月因不同原因行腹腔镜手术的 415 0例不同的手术方法并发症。　结果　腹腔镜手术并发症 18例 ,占 0 .43 % (18/4 15 0 )。其中伤口愈合延迟、皮下气肿、出血、脏器损伤分别占腹腔镜手术的 0 .10 % (4 /4 15 0 )、0 .14 % (6/4 15 0 )、0 .0 7% (3 /4 15 0 )、0 .12 % (5 /4 15 0 )。分别占腹腔镜手术并发症的 2 2 .2 % (4 /18)、3 3 .3 % (6/18)、16.7% (3 /18)、2 8.0 % (5 /18)。　结论　视野暴露困难、盆腹腔粘连、盲目钳夹电凝止血、手术操作不熟练、切口清洗消毒不彻底 ,是造成手术并发症的关键     

体重监测下使用硫代乙酰胺诱导大鼠肝硬化模型

目的探索根据体重变化监测肝硬化诱导过程中大鼠对硫代乙酰胺 (thioacetamide,TAA)反应的个体差异 ,以提高肝硬化形成率和质量。方法雄性Wistar大鼠 4 6只 (2 0 0～ 2 30 g) ,随机分为 3组。 1组 (2 0只 )以 0 0 3% (w/v)TAA作为饮用水 ,共 12周。 2组 (2 0只 )以 0 0 3%TAA作为初始浓度 ,然后根据每周体重变化调整饮用水中TAA浓度。 3组 (6只 )给予饮用水 ,作为对照组。结果 1组大鼠病死率为 30 % (6 / 2 0 ) ,肝硬化形成率仅 4 5 % (9/ 2 0 )。 2组病死率为 0 ,肝硬化形成率为 90 % (18/ 2 0 )。结论肝硬化诱导过程中大鼠对TAA反应的个体差异可根据每周体重变化加以监测。该法可降低大鼠病死率至 0 ,同时显著提高肝硬化形成率和质量。     

面神经的角神经解剖学研究

Objective To study the anatomy of angular nerve (AN), so as to provide safe approach for the denervation surgery of corrugator supercilii, depressor supercilii and proceeas. Methods 10 fresh cadaver (20 sides)were perfused and fixed with formalin. Dissection was performed in the 10 X operating microscope. The plexus of the zygomatic branch and the buccal branch were detected to confirm the AN. The relationship of AN with the surrounding blood vessels was observed. We tracked AN until it entered corrugator supercilii, depressor supercilii and procerus. Results ①AN was classified into Ⅰ, Ⅱ ,Ⅲ type according to its formation pattern. Type Ⅰ (20% , 4/20 sides) AN is single, which is mainly from the plexus of buccal branch plus the zygomatic branch from the orbicularis oculi muscle. In type Ⅱ (20% , 4/20 sides) , the single AN was formed by buccal branch plexus and zygomatic branch plexus in the "Four Muscle Gap". In type Ⅲ (60% , 12/20 sides) , the AN had two branches in the "Four Muscle Gap". ②The three types AN passed inferior to the support ligament at the suborbital part, and then transversed medial to the support ligament at the medial canthus, along the vessels of medial canthus. ③ The branch of AN enters the depressor supercilii or procerus 2. 19 to 4. 28 mm above the medial canthus ligament. The backward branch enters the levator labii superioris alaeque nasi 6. 89 to 9. 38 mm below the medial canthus ligament. Conclusions The approach of denervation surgery for AN should be performed medial to the support ligation, between 2. 19 mm above the medial canthus and 6. 89 mm below the medial canthus.     

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.     

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.     

Is the recovery profile of mivacurium independent of the rate of decay of its plasma concentration in patients with normal plasma cholinesterase activity?

Background: The duration of action of muscle relaxants is poorly correlated to the rate of decay of their plasma concentration. The plasma concentration of mivacurium may rapidly decrease below its active concentration because of the extensive hydrolysis of mivacurium. By inflating a tourniquet on one upper limb for 3 min after the administration of atracurium, mivacurium or vecuronium, we studied the influence of the initial decline of their plasma concentration on their effect. Methods: In 50 patients anaesthetised with thiopental, isoflurane and fentanyl, the effect of bolus doses of 0.15 or 0.25 mg . kg^?1 mivacurium (MIV 15, MIV 25), 0.3 or 0.5 mg . kg^?1 atracurium (ATR 30, ATR 50) and 0.06 or 0.1 mg . kg^?1 vecuronium (VEC 06, VEC 10) were measured on both arms (evoked response of the adductor pollicis to train-of-four stimulation every 12 s), a tourniquet being applied on one arm just before and during 3 min after the muscle relaxant bolus. Results: Tourniquet inflation of 3 min almost abolished the neuromuscular effect of mivacurium. In the vecuronium groups and in the ATR 50 group, tourniquet inflation did not modify the maximum degree of depression of the twitch response. Also, the duration of action of vecuronium was unaffected by the tourniquet. In the ATR 30 group, times to return of the twitch response to 25% (duration 25%) and 75% (duration 75%) of control response were significantly shorter in the cuffed arm, 23 min vs 27 min, and 41 min vs 45 min, respectively. In the ATR 50 group, only duration 25% was significantly shorter in the cuffed arm (41 min vs 45 min). Conclusion: The results suggest that the rate of decline of the plasma concentration of mivacurium is so rapid, that a very low and almost clinically ineffective concentration is present as soon as 3 min after its administration. The results also indicate that the recovery from a mivacurium-induced neuromuscular blockade is not influenced by the rate of decay of its plasma concentration in patients with genotypically normal plasma cholinesterase.     

Membranes in Artificial Organs

Abstract: Membrane processes play a pivotal and enabling role in modern replacement therapy for acute and chronic organ failure and in the management of immunologic diseases. In fact, virtually all contemporary extracorporeal blood purification methods employ membrane devices, and the next generation of artificial organs and tissue engineering therapies are almost certain to be similarly grounded in membrane technology. In this short essay, we comment on the similarities and differences among synthetic membranes and their natural counterparts and also provide a critical overview of the demographics and technology of hemodialysis, hemofiltration, apheresis, oxygenation, and emerging membrane technologies and applications.     

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.     

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.