青少年特发性脊柱侧凸支具治疗结束后近期矫正丢失及影响因素

目的:观察青少年特发性脊柱侧凸(adolescent idiopathic scoliosis,AIS)支具治疗结束后短期内侧凸的矫正丢失情况,并探讨其影响因素。方法:选取2002年10月～2007年12月在我院完成规范化支具治疗后短期随访的AIS患者84例,其中男4例,女80例。初诊时年龄10～15岁,平均12.8岁;Risser征0～3级,平均1.6级;主弯Cobb角20°～43°,平均29.5°。胸腰双主弯36例,单胸弯22例,单胸腰弯或腰弯26例。所有患者在初诊、复查时均摄佩带支具前后站立位全脊柱正位X线片。分别测定不同时期侧凸Cobb角,记录侧凸类型、Risser征、患者的生理年龄及月经初潮时间,分析去除支具后侧凸的矫正丢失情况及影响因素。结果:AIS患者支具治疗后主弯Cobb角的平均矫正率为12.4%,其中14例(16.7%)患者在治疗期间出现脊柱侧凸进展,不同弯型脊柱侧凸的侧凸矫正率、进展率比较差异无显著性(P0.05)。支具治疗结束时主弯Cobb角10°～37°,平均25.5°,明显小于初诊时的29.5°(P0.05),停用支具后6～18个月主弯Cobb角为27.2°,与支具治疗结束时比较无显著性差异(P0.05)。停用支具后,有15例(17.6%)患者出现脊柱侧凸进展,不同弯型脊柱侧凸进展差异无统计学意义(P0.05);侧凸进展的患者在支具治疗时主弯Cobb角的平均矫正率为23.3%,明显高于未出现侧凸进展患者的10.6%,且差异具有统计学意义(P0.05)。停用支具时不同Cobb角组后期出现侧凸进展的概率无显著性差异(P0.05)。结论:支具治疗能够有效控制AIS患者侧凸的进展。在结束支具治疗后短期内随访侧凸矫正基本稳定,但仍有一小部分患者会出现侧凸进展,这种进展与弯型、侧凸的严重程度无关,可能与支具治疗期间侧凸的矫正率较大有关。     

青少年特发性脊柱侧凸的支具治疗

目的探讨青少年特发性脊柱侧凸支具治疗的适应证,并评价其临床疗效。方法77例骨骼发育未成熟的青少年特发性脊柱侧凸患者接受Milwaukee支具或Boston支具矫正,男15例,女62例;年龄10～15岁,平均12.7岁。胸腰双主弯26例、单胸弯37例、单胸腰弯或腰弯14例。原发弯Cobb角22°～62°,平均35.9°;20°～35°者37例,>35°者40例。Risser征0度38例、Ⅰ度19例、Ⅱ度13例、Ⅲ度7例。每3～6个月定期复查,复查时均摄佩带支具前、后的站立位全脊柱正位X线片,测量初次就诊及末次随访时的Cobb角、顶椎旋转度及Risser征。结果全部病例随访24～60个月,平均30个月。29.9%的病例出现脊柱侧凸进展,不同类型脊柱侧凸中胸腰双主弯进展率最低,但与其他类型比较差异无显著性。Risser征越小,初诊支具矫正率越大、侧凸进展率越高,且Risser征Ⅰ度组(包括0度)与Ⅱ度组之间、Ⅰ度组与Ⅲ度组之间初诊支具矫正率的差异有显著性(P<0.05)。原发弯Cobb角20°～35°组的初诊支具矫正率大于Cobb角>35°组(P<0.05);而侧凸进展率低于Cobb角>35°组,但差异无显著性。21例因出现侧凸进展而采用手术矫形,支具治疗使其中13例的手术时间推迟了12～20个月。结论Risser征可作为预测青少年特发性脊柱侧凸支具矫正成功率的一个指标。不同类型脊柱侧凸中胸     

经后路多点锚定技术治疗Ⅰ型神经纤维瘤病伴营养不良性脊柱侧凸的临床疗效

[目的]探讨经后路多点锚定技术治疗Ⅰ型神经纤维瘤病伴营养不良性脊柱侧凸的临床疗效。[方法]回顾性研究2005年1月~2013年12月本科收治的Ⅰ型神经纤维瘤病伴营养不良性脊柱侧凸23例;年龄10~22岁,平均13.6岁;其中胸弯13例,胸腰双主弯4例,胸腰弯3例,双胸弯2例,腰弯1例;术前冠状面Cobb角48.9°~91.4°,平均68.3°;凸侧Bending相Cobb角40°~79.2°,平均57.4°;柔韧性8.3%~28.1%,平均15.7%;顶椎旋转度2°~3°,平均2.3°;矢状面胸椎后凸Cobb角46.4°~79.6°,平均58.2°,胸腰段后凸Cobb角21.1°~35.7°,平均28.3°。均采用经后路多点锚定技术进行矫形融合固定。[结果]随访12~96个月,平均52个月。术后冠状面Cobb角16.3°~46.7°,平均28.4°;顶椎旋转度1°~2°,平均1.2°;矢状面胸椎后凸Cobb角16.1°~38.3°,平均25.3°,胸腰段后凸Cobb角-4.3°~18.7°,平均8.9°;术后各指标均获得良好的矫正,侧凸矫正率为46.3%~74.1%,平均56.9%。末次随访时侧凸矫正丢失率仅3.1%,无神经系统并发症,仅1例假关节形成。[结论]经后路多点锚定技术治疗Ⅰ型神经纤维瘤病伴营养不良性脊柱侧凸可获得较满意的矫形融合效果。     

青少年特发性脊柱侧凸改良色努支具应用研究

[目的]评估改良色努支具治疗青少年特发性脊柱侧凸(AIS)的疗效。[方法]30例AIS患者应用改良色努支具进行治疗,其中男5例,女25例,平均随访12个月。记录初次就诊和末次随诊时躯干倾斜角、Cobb角、VAS评分和SRS-22得分。[结果]AIS患者躯干倾斜角治疗前平均为10.0°,改良色努支具治疗后平均为7.7°,差异有统计学意义(t=2.114,P=0.040)。Cobb角治疗前平均为33.7°,治疗后平均为26.2°,差异有明显统计学意义(t=2.867,P=0.006)。SRS-22量表中自我形象维度得分治疗前平均为3.20,治疗后平均为3.61,差异有明显统计学意义(t=-2.714,P=0.009)。改良色努支具治疗前后,AIS患者在VAS评分、功能活动、疼痛、心理健康维度得分差异没有统计学意义(P>0.05)。AIS患者对治疗的满意程度维度得分平均为4.12。[结论]改良色努支具能有效地控制青少年特发性脊柱侧凸畸形的进展,改善躯干外观,对患者的生活质量没有消极影响。     

青少年特发性脊柱侧凸患者术后生活质量的影响因素分析

[目的]分析各因素对青少年特发性脊柱侧凸患者术后生活质量的综合影响,为提高患者生活质量提供参考。[方法]选择2011年1月~2015年1月在本院手术的青少年特发性脊柱侧凸患者79例,之前均未接受任何治疗,详细统计患者性别、年龄、居住地、胸弯Cobb角、腰弯Cobb角、冠状面C_7铅垂线与骶骨正中线距离、矢状面C_7铅垂线与骶骨后上角距离、顶椎旋转度、双肩平衡等,采用SRS-30生活质量问卷进行评估,而后用多重线性回归模型预测各因素与青少年特发性脊柱侧凸患者术后生活质量的相关性。[结果]患者术后均获得不同程度改善,术后胸弯Cobb角平均20.7°,腰弯Cobb角平均12.8°,双肩高度差平均6.8 mm,C_7PL-CSVL平均13.7 mm,SVA平均22.9 mm,术后患者生活质量总分128.3分,各维度平均得分分别为疼痛(4.53)、心理(4.46)、功能/活动(3.73)、自我形象(4.28)、满意度(4.45)。男性患者在功能/活动维度(P=0.05)及满意度(P=0.037)上得分显著高于女性患者,城乡患者间得分无明显差异。[结论]不同影响因素对SRS-30问卷各个维度的影响权重各异,青少年特发性脊柱侧凸患者术后的生活质量是各个因素综合作用的结果。     

胸腰段特发性脊柱侧凸的前路矫正术

目的评价胸腰段/腰段特发性脊柱侧凸经前路矫正术的临床效果。方法1998年1月~2004年1月,76例胸腰段/腰段特发性脊柱侧凸患者接受前路选择性矫正融合术。患者共76例,男19例,女57例,平均年龄为16.2岁(13~27岁)。按照Lenke分型,Ⅴ型41例,Ⅵ型35例。其中Lenke Ⅴ型术前胸腰段侧凸Cobb角平均51.3°(38°~65°),胸段侧凸Cobb角平均35.5°(23°~41°);Lenke Ⅵ型术前胸腰段侧凸Cobb角平均53.4°(46°~68°),胸段侧凸Cobb角平均39.2°(27°~51°)。所有患者均接受侧前路矫正选择性胸腰段融合。术后以及随访中对胸腰段侧凸矫正以及胸段代偿矫正情况进行分析对比,同时采用SRS-22评分评价患者手术前后的功能状况。结果患者均安全完成手术,无严重并发症发生。所有患者均随访2年以上(2~5年)。Lenke Ⅴ型组术后胸腰段侧凸Cobb角平均11.2°(3°~15°),胸段侧凸Cobb角平均8.3°(2°~11°),最终随访时分别为13.2°(5°~17°)和10.1°(4°~15°),无躯干冠状面失代偿发生;LenkeⅥ型组术后Cobb角平均16.3°(8°~21°),胸段侧凸Cobb角平均13.7°(11°~19°),最终随访时分别为17.5°(11°~24°)和15.2°(14°~21°);仅1例发生躯干冠状面失代偿,但不需要进一步治疗。两组之间无统计学差异。所有患者均在术后以及最终随访时填写了SRS-22评分表,结果显示两组患者均对治疗结果表示满意。结论胸腰段/腰段特发性脊柱侧凸经前路矫正、选择性融合可以获得良好矫正,术后胸段弯曲能够获得较好的代偿矫正,并在远期随访中维持矫正效果和躯干冠状面的平衡。     

非手术方法治疗青少年特发性脊柱侧凸

[目的]比较分析不同的非手术方法治疗青少年特发性脊柱侧凸的疗效.[方法]于2010年1月～2011年12月,收治青少年特发性脊柱侧凸患者86例(Cobb角＜40°),随机分成4组,分别给予观察、支具治疗、电刺激治疗和支具结合电刺激治疗,随访时复查站立位全脊柱正侧位X线片,测量Cobb角,并计算治疗前后Cobb角的改变值,进行统计学分析.[结果]各组治疗前后Cobb角改变值均有显著性差异(P＜0.01),支具治疗组和支具结合电刺激治疗组的Cobb角改变值与电刺激治疗组行组间比较均有显著性差异(P＜0.05),支具治疗组的Cobb角改变值与支具电刺激组间比较无显著性差异(P＞0.05).[结论]观察组虽然无矫正畸形作用,但对Cobb角较小的患者进行短期观察可作为日后选择治疗方法的参考.支具疗法、电刺激疗法和支具联合电刺激疗法均能有效的控制侧凸畸形发展.支具疗法的疗效明显优于电刺激疗法,能明显矫正侧凸畸形.支具结合电刺激疗法与支具疗法的疗效相似,但因其存在发生并发症的可能,故应该谨慎应用.     

选择性前路胸腰段或腰段融合治疗青少年特发性脊柱侧凸

目的 评价选择性前路胸腰段或腰段融合治疗PUMCⅡd1型(Lenke5型)青少年特发性脊柱侧凸(AIS)的临床效果. 方法回顾性分析35例行选择性前路胸腰段或腰段融合的PUMCⅡd1型(Lenke5型)AIS病例.所有病例均行前路单棒节段性固定融合,随访18～42个月,平均36个月.术前、术后及随访时均摄站立位全脊柱正侧位X线片,对躯干偏移、上下融合椎邻近椎间盘开角、下固定椎的倾斜、冠状面和矢状面Cobb角进行测量分析.测量数据使用SPSS 11.0统计学软件进行分析.结果 胸腰弯或腰弯冠状面Cobb角术前平均45.6°,术后9.7°,末次随访14.4°.胸弯冠状面Cobb角术前平均29.7°,术后17.6°,末次随访20.1°.躯干偏移术前平均14.0 mm,术后14.8 mm,末次随访5.1 mm.下端固定椎(LIV)倾斜术前平均-21.8°,术后-1.5°,末次随访-2.1°.冠状面上端固定椎(UIV)上位椎间盘开角(UIVDA)及LIV下位椎间盘开角(LIVDA)术前分别为0.5°和0.6°,术后为0.9°和4.9°,末次随访时均显著加重,为3.0°和7.8°.矢状面胸段(T5～12)及胸腰段(T10～L2)曲度术后及末次随访时均保持良好.矢状面腰前凸(L1～S1)及固定融合节段Cobb角在术后有所减小,末次随访时均保持良好.所有病例末次随访时均未见假关节形成及其他并发症. 结论 选择性前路胸腰段或腰段融合是治疗PUMCⅡd1型(Lenke 5型)AIS的安全、有效的方法,融合节段上、下椎间盘开角增加及部分病例残余胸弯过大现象需进一步随访评估.     

合并胸腰段后凸的青少年特发性脊柱侧凸的临床研究

目的 探讨合并胸腰段后凸的青少年特发性脊柱侧凸(AIS)的临床特点和手术治疗策略. 方法对2001年1月至2007年1月收治的413例AIS患者进行回顾性分析,合并胸腰段后凸者共10例,其中男2例,女8例;年龄12～18岁,平均14.3岁.侧凸类型包括PUMC Ⅱb2型3例,Ⅱc 3型4例,Ⅱd2型1例,Ⅲb型2例.单纯后路内固定术8例,前路松解+后路内固定术2例.术前、术后及随访时摄X线片,对侧凸类型、Cobb角、顶椎旋转度、顶椎偏距、侧凸柔韧性、胸腰段后凸、冠状面及矢状面躯干偏移进行评测和分析.结果 本组患者中双弯8例,三弯2例;胸腰弯/腰弯Cobb角≥45°者7例,柔韧性指数≤70%者6例,顶椎旋转度≥Ⅱ度者9例.所有病例的融合范围均符合PUMC分型原则.手术前后平均胸弯冠状面Cobb角分别为71.7°和37.4°,平均矫正率为47.8%;手术前后平均胸腰弯/腰弯冠状面Cobb角分别为65.0°和27.8°,平均矫正率为57.2%;手术前后平均胸腰段后凸分别为35.5°和4.2°,平均矫正率为88.2%.全部病例随访12～72个月,平均23.1个月;最终随访时无躯干失平衡发生. 结论 合并胸腰段后凸的AIS一般多为双弯或三弯,胸腰弯/腰弯畸形往往比较严重,并有明显的旋转畸形.对合并胸腰段后凸的AIS,应融合胸腰弯/腰弯以防止术后发生失代偿或后凸加重, PUMC分型可以有效识别病变类型并指导融合范围的选择.     

哈尔滨市青少年脊柱侧凸普查与支具治疗结果分析

[目的]调查哈尔滨市青少年脊柱侧凸的患病率及类型,分析支具治疗的临床效果。[方法]于2005年10月～2009年10月对哈尔滨市城乡32所中、小学校6～16岁的24 362名中、小学生进行脊柱侧凸普查,统计患病率情况。根据特发性脊柱侧凸患者Cobb角大小不同,给予热塑支具治疗(Cobb角20°～40°)。每6个月复查1次,摄站立位全脊柱正侧位X线片,分析治疗结果。[结果]第一检结果阳性1 240名(5.09%),第二检阳性518名(2.13%),其中497名进行第三检,全脊柱正侧位X线片示Cobb角≥10°者423名,患病率为1.74%。特发性脊柱侧凸116例(Cobb角20°～40°)进行热塑支具治疗,支具治疗病例平均随访38个月,84例(72.4%)治疗有效,32例(27.6%)出现脊柱侧凸进展,治疗无效。Cobb角20°～30°组的矫正效果优于Cobb角30°～40°组,两组比较有显著差异(P<0.05)。[结论]通过普查,可以早发现、早诊断青少年脊柱侧凸,以便及时选择适当的方法进行治疗。热塑矫形支具治疗青少年特发性脊柱侧凸能够取得较好疗效,侧凸柔软性好,Cobb角较小,则矫正效果好。     

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.     

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.     

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.     

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.