影响脊柱术后感染内固定移除的因素分析

[目的]分析脊柱内固定术后感染治疗疗效,对影响脊柱内固定术后感染内固定移除的因素进行评估。[方法]2004年7月²012年12月共收治脊柱术后手术部位感染患者65例,男38例,女27例,平均(51.1±15.0)岁。手术部位:颈椎14例,胸椎5例,腰椎46例。所有脊柱术后感染患者均使用抗生素抗感染治疗,在静脉使用广谱抗生素前留取切口分泌物送检细菌培养和药敏试验,待细菌培养和药敏结果明确后调整抗生素。必要时联合彻底清创冲洗、对口置管冲洗引流,根据引流液培养结果决定冲洗量及拔除冲洗管和引流管。采用卡方检验分别分析内固定移除与性别、年龄、手术部位、术前住院时间、感染发生时间、感染部位、体温、切口渗液、切口红肿、切口疼痛、神经体征、病原菌种类和清创次数等因素的关系。采用Logistic回归对内固定移除的相关因素进行多因素分析。[结果]单因素卡方分析显示术前住院时间、感染发生时间、清创次数等因素与内固定移除有关;多因素Logistic回归分析显示清创次数是影响内固定移除的最重要因素。[结论]对于脊柱内固定术后感染,当清创次数达到2次时应考虑移除内固定,以利于有效地控制感染。     

VSD治疗胸腰椎后路内固定术后切口深部感染的应用

目的通过比较封闭负压引流装置(VSD)和常规闭式引流治疗胸腰椎后路内固定术后切口深部感染的效果。观察VSD治疗胸腰椎后路内固定术后切口深部感染的可行性。方法回顾性分析郑州大学第一附属医院骨一科2014-06—2017-06间收治的53例胸腰椎后路融合术后切口深部感染患者资料,均经保守治疗无效后行清创冲洗引流。根据引流方式不同分为2组,将行常规闭式引流的25例纳入对照组,将行VSD负压引流的28例纳入观察组。比较2组患者的清创次数及切口愈合时间,并观察血常规、血沉(ESR)、C反应蛋白(CRP)及微生物培养结果。结果单因素分析结果表明,2组患者首次清创术前性别、年龄、体质指数(BMI)、合并症、ASA评分、ESR、CRP等基线资料无显著性差异(P0.05)。所有患者切口最终均完全愈合。观察组患者清创次数及切口愈合时间均少(短)于对照组,差异有统计学意义(P0.05)。观察组中无患者因VSD使用出现脑脊液漏等相关并发症。细菌培养结果革兰氏阳性球菌者43例(包含7例多重耐药菌),革兰氏阴性杆菌者10例。经过早期清创、彻底引流及全身应用敏感抗生素后均获得满意治疗效果,且随访期间无感染复发病例。结论 VSD应用于切口深部感染可显著降低患者住院时间,减少治疗期间清创次数和抗生素应用周期,加速切口愈合。对于切口感染严重的患者将VSD埋入切口深部进行引流,取得了满意的临床效果。     

腰椎后路融合术后急性手术部位感染的危险因素分析

目的探讨腰椎后路融合术后发生急性手术部位感染的相关危险因素。方法回顾性分析2016年1月至2018年12月于我院脊柱外科行腰椎后路融合手术的330例病人的临床资料。病人主要诊断包括腰椎椎管狭窄、腰椎间盘突出症、腰椎骨折、肿瘤等。根据术后是否发生急性手术部位感染将病人分为感染组和非感染组,选择年龄、性别、身体质量指数(body mass index, BMI)、吸烟、高血压、糖尿病、骨质疏松症、手术节段数、手术时间、出血量、切口长度、术后引流时间、尿路感染和脑脊液漏等可能影响术后急性手术部位感染的因素,先后应用单因素分析和二元Logistic回归分析腰椎后路融合术后急性手术部位感染的危险因素。结果共有19例术后发生了急性手术部位感染,发生率为5.76%(19/330)。单因素分析结果显示:两组病人的年龄、BMI、糖尿病、骨质疏松、手术节段、手术时间、出血量、脑脊液漏、尿路感染以及切口长度的差异均有统计学意义(P均<0.05)。二元Logistic回归分析结果显示:BMI[OR=1.429,95%CI(1.059,1.929),P=0.020]、合并糖尿病[OR=9.568,95%CI(2.183,41.935),P=0.003]、手术时间[OR=8.868,95%CI(1.992,39.482),P=0.004]、切口长度[OR=7.257,95%CI(2.937,16.719),P<0.001]为腰椎后路融合术后急性手术部位感染的独立危险因素。结论为了降低腰椎术后急性手术部位感染的发生率,围术期应合理评估控制相关危险因素,以获得更好的治疗效果和病人满意度。     

后路长节段固定融合术治疗腰椎退行性疾病术后近端交界性后凸的相关因素分析

目的对后路长节段固定融合术治疗腰椎退行性疾病(lumbar degenerative diseases,LDD)术后近端交界性后凸(proximal junctional kyphosis,PJK)的相关因素进行分析,为其预防提供理论依据。方法纳入后路长节段固定融合术治疗的105例腰椎退行性疾病患者,随访18个月,将PJK患者设为观察组,非PJK患者设为对照组,调查两组患者一般资料以及影像学资料,采用单因素与多因素Logistic回归分析确定术后PJK的独立危险因素。结果 105例患者术后发生PJK 20例,发生率19.05%。两组上端固定椎(upper instrumented vertebra,UIV)位于胸腰段、身体质量指数(Body Mass Index,BMI)、近端交界性后凸角(proximal junctional kyphosis angle,PJKA)、合并骨质疏松、骶骨倾斜角(sacral slope,SS)差异有统计学意义(P0.05); Logistic回归分析结果显示:PJKA10°(OR=2.435)、UIV位于胸腰段(OR=1.764)、合并骨质疏松(OR=2.215)、SS25°(OR=1.976),均是术后发生PJK的独立危险因素。结论 PJK发生率较高,UIV位于胸腰段、PJKA10°、合并骨质疏松、SS25°,均会增加后路长节段固定融合术治疗LDD术后PJK发生的风险。     

胸腰椎后路内固定术后深部感染的治疗

目的 探讨胸腰椎后路内固定术后深部感染的特点与治疗方法。方法对36例胸腰椎内固定术后感染患者的临床表现、生化和细菌学检查及治疗进行分析。根据发生感染时间的不同分为早期感染14例,迟发性感染22例。结果早期感染一般伴有全身症状,白细胞计数及红细胞沉降率（ESR）升高,脓液培养主要为金色葡萄球菌、大肠杆菌等致病力强的细菌,迟发性感染一般无全身症状,白细胞计数不升高,ESR升高,脓液培养主要为类白喉杆菌、表皮葡萄球菌等致病菌力较弱的皮肤正常菌群。早期感染患者予以清创、持续冲洗引流。除3例反复清创无效,将内固定取出以外,其余内固定均予保留。迟发性感染者予以内固定取出、清创、持续冲洗引流。33例平均随访2．6年,经上述治疗后仅1例患者早期深部感染迁延不愈致椎体骨髓炎,术后3个月伤口再次出现流脓,其余均愈合。结论胸腰椎固定后早期感染及迟发性感染的发生机理可能存在差异。早期感染由致病力强的细菌引起,累及范围广。而迟发性感染由致病菌弱细菌引起,发展慢且较局限。对早期深部感染可以保留内固定行病灶清除,持续冲洗引流,多次清创无效,感染控制不佳则需要早日将内固定取出,以免炎症扩散。而迟发性感染则需取出内固定,否则难以消除炎症。     

后路腰椎内固定术后手术部位感染的危险因素分析

目的:探讨后路腰椎内固定术后手术部位感染的危险因素,为降低手术部位感染的发生率提供参考依据。方法:回顾我科2016年1月1日～2018年12月31日实施后路腰椎内固定手术的1073例患者,男516例,女557例,年龄18～84岁(54.67±13.23岁),将术后手术部位感染的患者纳入感染组,其余患者纳入非感染组。收集两组患者的性别、年龄、诊断、体重指数(BMI)、合并糖尿病和高血压情况、手术时间、术中出血量、是否输血、吸烟史、术前美国麻醉医师协会(ASA)分级、术前使用激素情况、内固定节段数、是否固定至慨骨或骨盆、是否为翻修手术、手术开始时段等资料,进行单因素分析,对阳性结果进行多因素Logistic回归分析。结果:1073例患者中发生手术部位感染19例,感染发生率为1.77%,其中男11例,女8例,年龄18～77岁(54.89±16.67岁)。单因素分析显示两组肥胖(BMI≥28kg/m~2)、合并糖尿病、手术时间、手术开始时段等因素存在统计学差异(P0.05);性别、年龄、疾病种类、合并高血压、出血量、是否输血、吸烟史、术前ASA分级、术前使用激素、内固定节段数、是否固定至慨骨或骨盆、是否为翻修手术等因素无统计学差异(P0.05)。多因素Logistic回归结果显示肥胖(OR=6.704,P=0.005)、合并糖尿病(OR=4.071,P=0.008)、较长手术时间(OR=7.102,P=0.000)、手术开始时段为晚间(OR=3.981,P=0.018)是术后手术部位感染的独立危险因素。结论:肥胖、合并糖尿病、较长手术时间、手术开始时段为晚间的患者后路腰椎内固定术后发生手术部位感染的风险较高,应采取有针对性的预防措施,以期最大限度降低术后手术部位感染的发生。     

腰椎后路内固定术后深部感染21例治疗体会

目的探讨腰椎后路内固定术后深部感染行清创闭式冲洗引流术的临床效果。方法回顾性分析自2009-01—2013-11因腰椎后路内固定术后出现深部感染而接受清创闭式引流术21例,所有患者均行保留内固定材料的腰椎清创闭式冲洗引流术,根据体温、冲洗引流情况、炎症指标变化趋势确定感染控制情况。结果 19例(90.5%)经清创闭式冲洗引流术成功控制感染并保留内固定材料,其中1例行2次清创冲洗引流术,18例均行1次冲洗引流术即控制感染。2例MRSA感染患者中,1例经1次清创闭式冲洗引流术及1例经3次手术治疗后细菌培养仍有MRSA感染,后行内固定材料取出并继续行闭式冲洗引流治疗,最终感染控制。保留内固定材料的19例术后短期复查均未见螺钉松动情况;9例随访9个月以上,均获得植骨融合。结论清创闭式冲洗引流术能有效控制腰椎后路内固定术后感染并保留腰椎内固定材料。MRSA感染患者能否能通过清创闭式冲洗引流术保留内固定材料还需要进一步研究。     

腰椎融合术后早期下肢深静脉血栓形成的相关危险因素分析

目的 :探讨腰椎融合术后早期下肢深静脉血栓(deep venous thrombosis,DVT)形成的危险因素。方法:选取于2015年7月~2017年5月在广西壮族自治区人民医院骨科接受腰椎后路椎间融合术治疗的患者共165例,依据术后早期超声检查结果双下肢有无血栓形成,分为DVT组和非DVT组。对比两组患者的性别、年龄、体重指数、糖尿病、高血压病、术前凝血四项、D-二聚体、融合节段数、手术时间、术中输血、术后使用抗凝药、术后卧床时间等指标,再采用Logistic多因素回归分析进行统计学分析。结果:共纳入165例患者,术后并发下肢DVT者24例,发生率为14.5%。与非DVT组相比较,单因素χ~2检验显示两组在年龄、体重指数、手术时间、术中输血、术后卧床时间等指标差异具有统计学意义。多因素Logistic回归分析显示,年龄≥60岁(OR=6.444,95%CI=2.116~19.628)、体重指数≥24kg/m~2(OR=4.463,95%CI=1.603~12.426)、术中输血(OR=3.484,95%CI=1.110~10.932)、术后卧床天数≥5d(OR=3.155,95%CI=1.027~9.695)是腰椎融合术后早期并发下肢DVT的独立危险因素。结论:年龄≥60岁、体重指数≥24kg/m2、术中输血、术后卧床天数≥5d的患者腰椎融合术后早期易出现下肢DVT形成。     

闭合性胫骨平台骨折切开复位内固定术后深部感染的危险因素

目的探讨闭合性胫骨平台骨折切开复位内固定术后深部感染的发生率，并分析其相关危险因素。 方法回顾性分析2012年1月至2018年6月张家港市第五人民医院骨科收治的252例闭合性胫骨平台骨折并接受切开复位内固定手术的患者。收集患者术前基本资料和感染相关危险指标（包括创伤及手术相关指标）；根据是否发生深部感染分为感染组（14例）和未感染组（238例）；采用Logistic多因素回归分析评价闭合性胫骨平台骨折感染发生的高危因素。 结果闭合性胫骨平台骨折切开复位内固定术后深部感染最常见的病原菌为金黄色葡萄球菌（9/14、64.29%），其中44.44%（4/9）为耐甲氧西林金黄色葡萄球菌（MRSA）。与未感染组相比，感染组患者住院时间显著延长[（31.3 ± 16.5）d vs. （16.6 ± 4.8）d，t = 21.162、P < 0.001]、术中失血量增多[（455.2 ± 713.1）ml vs. （255.7 ± 330.8）ml，t = 4.115、P = 0.016]，手术时间延长[（196.4 ± 98.0）min vs. （124.5 ± 56.4）min，t = 10.522、P < 0.001]，差异均有统计学意义。单因素分析显示高体重指数（BMI）（> 26.4 kg/m²）（χ² = 12.428、P < 0.001）、美国麻醉医师协会（ASA）分级≥ 3级（χ² = 10.333、P = 0.001）、Schatzker Ⅴ和Ⅵ（χ² = 4.166、P = 0.041）、手术时间延长（χ² = 9.175、P = 0.002）均为发生深部感染的高危因素。Logistic多因素回归分析显示BMI> 26.4 kg/m²（OR = 1.192、P = 0.011）、手术时间> 148 min（OR = 3.769、P = 0.008）和ASA分级≥ 3级（OR = 1.240、P = 0.020）均为发生深部感染的独立危险因素。 结论胫骨平台骨折切开复位内固定术后深部感染发生率较高，高BMI、手术时间延长以及ASA分级≥ 3级为深部感染发生的独立危险因素。     

糖尿病患者脊柱后路内固定术后手术部位感染的危险因素:一项多中心研究

[目的]探讨糖尿病患者脊柱后路内固定术后发生手术部位感染的危险因素。[方法]回顾性分析三家医院自2011年1月²013年9月间共322例合并糖尿病的脊柱后路内固定手术患者的临床资料,分为感染组与未感染组,单因素分析对比两组患者在危险因素方面的差异性,并进行Logistic多因素回归分析。[结果]本组322例患者中13例发生手术部位感染,感染率为4.0%。感染组与未感染组单因素分析发现BMI、手术时间、尿蛋白阳性和术前依赖胰岛素等4个指标的差异有统计学意义;多因素回归分析显示,导致手术部位感染的独立危险因素包括BMI(OR=1.867,P=0.032)、尿蛋白阳性(OR=2.978,P=0.001)和手术时间(OR=1.366,P=0.028)。[结论]体重指数、尿蛋白阳性和手术时间是糖尿病患者行脊柱后路内固定术后发生手术部位感染的独立危险因素。     

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.     

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.