颜面部神经纤维瘤病连续整形修复术一例

目的 报道1例连续手术整形修复面部巨大神经纤维瘤病,探讨其面部严重畸形的修复整形方法. 方法 患者,男,22 岁.神经纤维瘤病呈"象面"严重畸形.患者右颜面巨大囊袋样包块29 cm×17 cm,侵及额顶、颞部及鼻口部,右眼球脱出,右睑裂 8 cm,右鼻孔 8.5 cm,大口畸形.CT 及 MRI 检查右枕骨缺损,右侧眼眶内下壁骨质变形缺损下移,额颞脑组织通过缺损疝出,右上、下颌骨变薄变形.一期手术面部肿瘤主体切除,将脱出变性眼球及变性腮腺摘除,行眼眶底钛网重建,组合皮瓣成型术,切除摘出物重4 kg.二期手术时于4个月后行残余肿瘤继续切除,阔筋膜悬吊,组合瓣鼻唇整形术.三期手术于二期术后4个月进行,再次切取阔筋膜悬吊,面部精细整形术. 结果 8个月后手术完成,术后随访4个月,面部整形效果满意.患者生活自如,步态平稳,能平卧. 结论 对于面部巨大神经纤维瘤,手术治疗是目前唯一可行的方法.连续分期整形术,可根据分期手术结果充分调整皮瓣设计及成型方法,同时多次修复悬吊可最大程度减少组织下垂,是一种较为实用安全的方法.     

体表神经纤维瘤的手术治疗探讨

目的：探讨体表神经纤维瘤的切除及创面修复的方法。方法：24例患者均行手术,其中切除后直接缝合13例,皮瓣转移6例,皮片移植4例,1例行肿瘤切除术同时行截肢术。术中采用肿胀麻醉技术,控制性降压技术等治疗方法。结果：20例患者Ⅰ期愈合,4例部分伤口裂开,经换药而愈。有两例巨大神经纤维瘤术中予以输血,其余病人未予输血。结论：对体表神经纤维瘤行切除手术,术中采用合适技术,可显著减少术中出血,降低手术风险,创面修复应根据瘤体大小及部位选择不同的修复方法。     

手术治疗体表血管瘤及脉管畸形

目的 总结手术治疗体表血管瘤及脉管畸形的方法及临床疗效.方法 2003年5月-2006年12月,收治145例体表血管瘤及脉管畸形患者.男81例,女64例;年龄2个月～40岁,中位年龄17岁.病程2个月～40年.病变分布于头面部85例,四肢34例,躯干26例.病变范围为1 cm×1 cm～27 cm×24 cm.术中病变切除后直接缝合40例;采用3 cm×2 cm～18 cm×11 cm局部皮瓣移位修复21例,供瓣区直接缝合18例,腹部取皮回植3例;采用5 cm×3 cm～27 cm×18 cm中厚皮片移植84例,其中61例腹部供皮区直接缝合,5例大腿供皮区采用刃厚皮片游离移植修复,18例血管瘤病变区皮肤原位回植.结果 术后病理检查:毛细血管瘤38例,微静脉畸形23例,静脉畸形67例,动静脉畸形15例,淋巴管畸形2例.6例植皮患者术后发生皮片部分坏死,其中1例伴颅骨外露,经局部筋膜瓣移位修复联合植皮后愈合,5例经换药后Ⅱ期愈合;其余患者皮瓣及皮片均顺利成活,供受区切口均Ⅰ期愈合.患者均获随访,随访时间1～3年.12例于术后6个月～2年复发,其中动静脉畸形4例,静脉畸形7例,微静脉畸形1例,均再次手术切除后治愈.余患者伤口愈合良好,未见复发.结论 广泛彻底手术切除是治疗体表血管瘤及脉管畸形的有效方法之一,术后应密切随访有无病变复发,并及时对症处理.     

Ⅰ型神经纤维瘤病合并腹腔恶性神经鞘瘤一例及文献复习

Ⅰ型神经纤维瘤病属于神经皮肤综合征或斑痣性错构瘤病,病变多位于皮下,位于纵隔且合并腹腔恶性外周神经鞘瘤的病例未见报道.现报道首都医科大学附属北京友谊医院胸外科治疗的Ⅰ型神经纤维瘤病合并腹腔恶性神经鞘瘤1例,并结合文献复习,讨论Ⅰ型神经纤维瘤病及合并恶性神经鞘瘤的临床特点、病理特征、诊疗及随访. 1 临床资料 患者,女,22岁.入院前18个月在外院行左肘、臀、左足肿物切除,术后病理提示"神经纤维瘤病".     

体表恶性肿瘤切除后的皮瓣修复

目的探讨体表恶性肿瘤切除后局部组织严重缺损的有效修复方法。方法采用吻合血管的游离皮瓣和邻近的轴型或随意皮瓣修复体表恶性肿瘤切除后的组织缺损，并尽可能地纠正畸形，恢复功能。结果临床应用１７例皮瓣全部成活，伤口均在术后１０～１５ｄ愈合拆线，功能恢复良好。１４例外形满意，２例稍微臃肿，１例有“猫耳”形成经再次手术修复满意。结论携带其他组织的复合皮瓣血运丰富，修复能力强，是目前体表恶性肿瘤切除后较为理想的修复方法，适合于部位深和范围广的体表肿瘤切除后局部组织严重缺损的修复。     

软组织重建在骨与软组织肿瘤外科治疗中的应用

目的回顾不同部位骨与软组织肿瘤切除术后软组织重建方法及临床疗效,探讨合理的软组织重建策略。方法 2003年6月-2010年12月,收治因骨或软组织肿瘤进行外科切除并接受皮瓣、肌瓣或肌皮瓣修复重建患者90例。其中男59例,女31例;年龄9～85岁,中位年龄37.2岁。骨原发或转移性肿瘤52例,软组织原发肿瘤38例。75例为肿瘤切除后一期软组织重建;7例因伤口不愈合行清创后软组织重建;8例因伤口感染行清创、负压封闭引流,二期软组织重建。皮瓣类型:腓肠肌肌瓣40例,背阔肌肌(皮)瓣6例,腹直肌肌(皮)瓣4例,臀大肌肌皮瓣、胸大肌肌瓣、交腹皮瓣各1例,局部转移皮瓣27例,带血管蒂皮瓣5例,单纯游离植皮5例。皮瓣范围为6.5 cm×4.5 cm～21.0 cm×9.0 cm。结果术后87例皮瓣成活;Ⅰ期愈合81例;Ⅱ期愈合6例,其中2例皮瓣部分坏死,经换药后成活,3例皮瓣延迟愈合,1例伤口轻度感染,经保守治疗后愈合。软组织重建失败3例,均为皮瓣坏死合并感染,经清创二次皮瓣转移后愈合。供区创面均Ⅰ期愈合,移植皮片完全成活。73例获随访,随访时间10～102个月,平均36.1个月。6例患者于术后2～27个月,平均8.2个月出现局部复发并接受二次手术切除。13例于术后6～34个月,平均19.2个月死于原发病。结论骨与软组织肿瘤切除后常造成较大的软组织缺损,选择适当的肌(皮)瓣进行软组织重建可以达到理想的伤口闭合,减少术后伤口并发症,有利于术后功能恢复。     

旷置术在面部特殊部位体表肿瘤切除整形修复中的疗效分析

目的探讨旷置术在面部特殊部位体表肿瘤切除整形修复中的疗效。方法对12例患者的面部特殊部位体表肿瘤进行手术切除,术后创口旷置不予缝合,定期换药,并给予定期复查,观查组织愈合情况。结果本组共12例患者,术后随访3~6个月,无一例出现感染、延迟愈合;患者愈合后的皮肤颜色、皮肤弹性均接近正常组织,面部表情自如,无一例患者出现感觉障碍、器官畸形、周围组织凹陷等并发症。结论旷置术治疗面部特殊部位体表肿瘤切除术后创口整形修复,能有效减少术中损伤,避免传统植皮术造成的一系列并发症,疗效较满意。     

皮肤恶性肿瘤的手术治疗

目的 为治疗皮肤恶性肿瘤提供良好的手术治疗方法.方法 手术治疗方法为彻底切除皮损,应用直接缝合和皮片移植及皮瓣转移等方法整形修复创面或重建体表缺损器官.结果 手术治疗皮肤恶性肿瘤146例患者,随访3个月至10年,术后复发率低,效果满意.结论 手术治疗皮肤恶性肿瘤仍是目前理想的治疗方法.     

踝关节三角韧带损伤的手术治疗及效果

目的：探讨踝关节三角韧带损伤手术治疗的重要性。方法：2002年至2008年治疗伴有三角韧带损伤的踝关节骨折61例,男39例,女22例;年龄14～71岁,平均41岁。均采用切开复位和坚强内固定,并修复重建三角韧带,恢复踝关节内外侧结构的稳定性。结果：61例中59例切口Ⅰ期愈合;2例术后外踝伤口浅表感染,经换药于术后3周愈合,内踝伤口全部Ⅰ期愈合。全部病例获得随访,时间5～30个月。平均17个月。按疗效评定标准,本组优35例,良13例,可13例。结论：强调踝关节骨折切开解剖复位、坚强内固定的同时,应充分重视修复重建三角韧带。     

头皮恶性肿瘤外科切除后的修复

目的 总结不同手术方法修复与重建头皮恶性肿瘤术后缺损,评价其临床效果. 方法 1995 年1 月-2004 年9月,对70例头皮恶性肿瘤患者行手术治疗,其中男41例,女29例;年龄30～85岁,平均50.3岁.病程2周～3年,平均 3.5 个月.基底细胞癌 31 例,鳞状细胞癌24例,恶性黑色素瘤8例,纤维肉瘤4例,脂肪肉瘤2例,血管肉瘤 1 例.病变范围 1.0 cm×0.5 cm～10.0 cm×8.0 cm.根治性切除肿瘤后缺损3 cm×3 cm～12 cm × 11 cm,采用中厚皮片移植 51 例,邻近头皮瓣移位12例,颈肩随意皮瓣移位2例,斜方肌肌皮瓣移位3例,桡动脉逆行岛状皮瓣2例,切取范围 5 cm×4 cm～18 cm × 12 cm. 结果 67 例皮片及皮瓣成活,伤口Ⅰ期愈合;2例皮瓣远端坏死,经过换药后Ⅱ期愈合;1 例桡动脉逆行岛状皮瓣感染,对症处理后愈合.供区均Ⅰ期愈合.55例患者获随访 1～5年,5例复发.植皮患者中鳞状细胞癌患者和纤维肉瘤患者各1例,分别于术后1年及2年半复发,均再次行根治性切除后采用皮瓣移位修复刨面;皮瓣移位患者中血管肉瘤患者及鳞状细胞癌患者各1例于术后6个月及3个月复发放弃治疗,1 例纤维肉瘤患者术后2年复发,再次根治性切除后采用皮瓣移位修复创面.余患者均存活良好. 结论 头皮恶性肿瘤应早期诊断、及时治疗,广泛彻底切除并进行合理的创面修复是有效的治疗方法.     

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.