地氟醚和丙泊酚对颅内动脉瘤夹闭术患者收缩和舒张脑血管物质的影响

目的比较地氟醚和丙泊酚麻醉下颅内动脉瘤患者行夹闭术术中血管紧张素Ⅱ(AT-Ⅱ)、内皮素(ET)和降钙素基因相关肽(CGRP)的变化。方法择期开颅动脉瘤夹闭术患者88例,随机分为地氟醚组(n=45)和丙泊酚组(n=43),以吸入地氟醚或静注丙泊酚维持麻醉。分别于麻醉诱导前、剪硬膜、夹闭动脉瘤和动脉瘤夹闭后30 min采集动脉血,应用放免法检测血浆AT-Ⅱ、ET和CGRP的浓度。结果两组AT-Ⅱ四个时点间及组间比较差异均无显著意义;丙泊酚组夹闭动脉瘤时ET较剪硬膜时明显升高(P<0.05);组间比较,夹闭动脉瘤时丙泊酚组ET明显高于地氟醚组(P<0.05);两组剪硬膜、夹闭动脉瘤和动脉瘤夹闭后30 min CGRP较麻醉诱导前均有所降低。结论丙泊酚麻醉下夹闭动脉瘤时缩血管物质ET明显升高,而地氟醚麻醉下无此现象,提示丙泊酚麻醉中应注重扩血管治疗,以防急性脑血管痉挛的发生,地氟醚可能更适合应用于开颅动脉瘤夹闭术。     

地氟烷麻醉颅内动脉瘤夹闭术中收缩和舒张脑血管物质的变化

目的 观察地氟烷麻醉期间颅内动脉瘤病人行夹闭术中血管紧张素Ⅱ(AT-Ⅱ)、内皮素(ET)和降钙素基因相关肽(CGRP)的变化。方法 颅内动脉瘤拟行择期开颅动脉瘤夹闭术病人45例,麻醉诱导后气管插管控制呼吸,地氟烷维持麻醉(MAC1.0～1.5)。分别于麻醉诱导前(T_1)、剪硬膜(T_2)、夹闭动脉瘤(T_3)和动脉瘤夹闭后30min(T_4)4个时点采集动脉血,应用放免法检测血浆中AT-Ⅱ、ET和CGRP的浓度。结果 4个时点AT-Ⅱ均在正常值范围。ET于地氟烷麻醉中3个时点明显低于T_1(P<0.01)。麻醉中3个时点CGRP与T_1比较无统计学意义。结论 地氟烷麻醉下开颅动脉瘤夹闭术中缩血管物质降低,但舒血管物质不变,提示麻醉中应注重扩血管治疗,预防术中急性脑血管痉挛的发生。     

异丙酚-芬太尼麻醉下颅内动脉瘤夹闭术中患者收缩和舒张脑血管物质的变化

目的观察异丙酚-芬太尼麻醉下颅内动脉瘤夹闭术中患者血浆血管紧张素Ⅱ(AT Ⅱ)、内皮素(ET)和降钙素基因相关肽(CGRP)的变化。方法颅内动脉瘤破裂后2周择期行颅内动脉瘤夹闭术患者43例。静脉注射芬太尼2μg·kg-1、维库溴铵0．1 mg·kg-1、异丙酚2 mg·kg-1麻醉诱导后气管插管,持续输入异丙酚6 mg·kg-1·h-1维持麻醉,并间断追加芬太尼2 μg·kg-1和维库溴铵。分别于麻醉诱导前(T1)、剪硬膜(T2)、夹闭动脉瘤(T3)和动脉瘤夹闭后30 min(T4)时采集动脉血,应用放免法测定血浆AT-_Ⅱ、ET和CGRP的浓度,并监测平均动脉压(MAP)和心率(HR)。结果血浆AT-Ⅱ浓度和HR在各时间点比较差异无统计学意义(P>0．05),且均在正常范围内。与T1比较,血浆 CGRP和MAP在T2-4明显降低(P<0．05或0．01),但MAP仍在正常范围内。与T2比较,血浆ET浓度在T3时升高(P<0．05)。结论在异丙酚-芬太尼静脉麻醉下,动脉瘤夹闭术中患者血液中收缩血管的物质升高,舒张血管的物质降低,应注意预防急性脑血管痉挛的发生。     

持续输注尼莫地平对颅内动脉瘤夹闭术中脑血管痉挛的影响

目的 了解颅内动脉瘤夹闭术中异氟醚麻醉复合输注尼莫地平对脑血管痉挛的影响。方法择期颅内动脉瘤夹闭术患者30例,随机表法分为两组:异氟醚组和尼莫地平组(各15例),异氟醚组术中吸入1个肺泡气最低有效浓度(MAC)异氟醚维持麻醉;尼莫地平组在诱导后输注尼莫地平20 μg·kg-1·h-1至手术结束后,同时吸入1 MAC异氟醚维持麻醉。术中于动脉瘤夹闭前、夹闭后即刻、2 h、4 h取脑脊液采用酶联免疫吸附试验法测定S100B含量;于动脉瘤夹闭前后测定载瘤动脉近心端及远心端血流速度。结果(1)尼莫地平组在动脉瘤夹闭前后脑脊液SIOOB含量无显著变化,而异氟醚组在动脉瘤夹闭后4 h S100B含量显著升高(F=4.11,P<0.05)。(2)尼莫地平组在动脉瘤夹闭前后载瘤动脉近心端血流速度[(15±9)与(19±8)cm／s]显著低于异氟醚组[(24±13)与(26±10)cm／s,t=2.08,P<0.05],而远心端血流速度无显著性差异。结论在颅内动脉瘤夹闭术中持续输注尼莫地平20μg·kg·-1·h-1对脑血管痉挛有一定预防作用。     

异氟醚控制性降压对颅内动脉瘤夹闭术病人脑脊液游离脂肪酸浓度的影响

目的探讨异氟醚控制性降压对颅内动脉瘤夹闭术病人脑脊液游离脂肪酸(FFAs)浓度的影响。方法择期行颅内动脉瘤夹闭术病人30例,ASAⅠ级或Ⅱ级,随机分为2组(n=15):对照组(A组)和控制性降压组(B组)。2组均在术中持续吸入异氟醚维持麻醉,A组术中呼气末异氟醚浓度为1.2%;B组切开硬脑膜时开始行异氟醚控制性降压,平均动脉压(MAP)下降幅度为基础值的30%～40%,夹闭动脉瘤即刻开始降低异氟醚吸入浓度停止控制性降压,使血压回升至降压前水平。分别于麻醉诱导前(T_0)、硬脑膜切开即刻(T_1)、硬脑膜切开后10、20、30min(T_(2-4))、动脉瘤夹闭后即刻(T_5)、动脉瘤夹闭后10、20、30min(T_(6～8))记录血液动力学指标;于T_1、L_5动脉瘤夹闭后2、4h(T_(9.10))取脑脊液,测定FFAs浓度。结果(1)B组硬脑膜切开后MAP由(96±9)mm Hg降至(62±4)mm Hg(P<0.05或0.01),夹闭动脉瘤后MAP恢复至(78±11)mm Hg,心输出量和心率无明显变化(P>0.05)。(2)B组在T_5、T_9、T_(10)时脑脊液FFAs浓度增高(P<0.05),B组FFAs浓度增高的程度高于A组(P<0.05)。结论异氟醚控制性降压可以增加颅内动脉瘤夹闭术病人脑脊液中FFAs的浓度。     

末梢灌注指数监测地氟醚诱发患者交感神经兴奋的评价

目的 评价末梢灌注指数(TPI)监测地氟醚诱发的患者交感神经兴奋作用.方法 择期全麻患者48例,年龄25～60岁,ASA Ⅰ或Ⅱ级,随机分为3组(n=16):七氟醚组(Ⅰ组)、地氟醚组(Ⅱ组)和地氟醚+异丙酚组(Ⅲ组).气管插管后Ⅰ组和Ⅱ组地氟醚或七氟醚呼气末浓度依次快速达到0.5 MAC、1.0 MAC和1.5 MAC,并在每个水平维持5 min.Ⅲ组在气管插管后靶控输注异丙酚.血浆靶浓度至1μg/ml,地氟醚呼气末浓度依次快速达到0.5 MAC、1.0 MAC,并在每个水平维持5 min.分别在给予咪达唑仑后5 min(T0)、麻醉诱导后3 min(T1)、插管后即刻(T2)、呼气末浓度达到0.5 MAC(T3)、0.5 MAC后5 min(T4)、1.0 MAC(T5)、1.0MAC后5min(T6)、1.5MAC(T7)、1.5MAC后5min(T8)时记录心率(HR)、平均动脉压(MAP)、TPI、脑电双频谱指数,并在T0、T1、T2、T5、T7时测定血浆肾素活性和血管紧张素Ⅱ水平.结果 与T4时比较,Ⅱ组T5时,IPI降低(P<0.05);与T7时比较,Ⅱ组T4～6、T8时HR、MAP降低,T3～6、T8时TPI降低(P<0.05);与Ⅰ组比较,Ⅱ组T7时HR、MAP升高,TPI降低(P<0.05);Ⅱ组T5和T7时TPI出现变化最大值的时间短于HR、MAP;ATPI与△HR、AMAP呈负相关(r=-0.593,P<0.05;r=-0.591,P<0.05);与Ⅰ组比较,Ⅱ组血浆肾素活性和AT-Ⅱ浓度升高(P<0.05).结论 TPI可灵敏地反映地氟醚诱发的患者交感神经兴奋.     

异氟醚控制性降压对颅内动脉瘤夹闭术病人脑脊液中S100B蛋白含量的影响

目的 对颅内动脉瘤夹闭术病人采用异氟醚控制性降压,测定动脉瘤夹闭前后脑脊液中S100B蛋白含量,研究异氟醚控制性降压对脑功能的影响。方法 择期颅内动脉瘤夹闭术病人30例,ASA Ⅰ～Ⅱ级,随机分为两组:异氟醚降压组(n=15)和异氟醚非降压组(n=15)。非降压组术中吸入异氟醚维持麻醉,呼气末浓度为1.2％。降压组行异氟醚控制性降压,平均动脉压下降幅度30％～40％,夹闭动脉瘤后降低异氟醚吸入浓度,终止降压。分别于降压前、降压后30 min、动脉瘤夹闭后即刻、停止降压后30 min(非降压组于相应时间)测定循环指标变化;于降压前、动脉瘤夹闭后即刻、2、4 h取脑脊液测定S100B蛋白含量。结果 (1)异氟醚降压后30min平均动脉压由诱导前的(95±12)mm Hg降至(59±5)mm Hg,停止降压后30 min血压回升至(75±8)mm Hg。降压后外周血管阻力及心肌收缩加速度下降,但心率及心输出量均无显著性变化。(2)降压组动脉瘤夹闭后4 h脑脊液中S100B浓度明显高于非降压组(P<0.01),而非降压组脑脊液中S100B浓度轻微升高(P<0.05)。结论 在颅内动脉瘤夹闭术中应用异氟醚控制性降压可能加重了术后脑损伤,不利于病人围麻醉期脑功能的保护。     

七氟醚与异丙酚对颅内动脉瘤夹闭术患者脑能量代谢影响的比较

目的 比较七氟醚与异丙酚对颅内动脉瘤夹闭术患者脑能量代谢的影响.方法 择期拟行颅内动脉瘤夹闭术的患者68例,ASA分级Ⅱ级或Ⅲ级,年龄22 ～ 62岁,体重52～81 kg,Hunt- Hess 分级Ⅱ或Ⅲ级,采用随机数字表法,将其随机分为2组(n=34):异丙酚组(P组)和七氟醚组(S组).麻醉诱导时P组靶控输注异丙酚,血浆靶控浓度2.0 μg/ml,S组吸入8％七氟醚.麻醉维持时P组靶控输注异丙酚,血浆靶浓度1.5 μg/ml,S组吸入2％七氟醚.于临时阻断前5 min(T0)、临时阻断5 min(T1)、10min(T2)、15 min(T3)、动脉瘤夹闭10 min (T4)、20 min (T5)和40 min (T6)时,收集脑组织微透析液,采用邻苯二甲醛柱前衍生反相高效液相色谱分析法结合荧光法检测微透析液葡萄糖、乳酸和丙酮酸浓度,计算乳酸/丙酮酸比(L/P比).结果 与P组比较,S组T1～ T6时微透析液葡萄糖、乳酸和丙酮酸浓度升高,T2～T4时L/P比降低(P＜0.05).与T0时比较,两组T1～T6时微透析液葡萄糖浓度降低,乳酸浓度升高,T1～T4时丙酮酸浓度降低,T5、T6时丙酮酸浓度升高,T1～T5时L/P比升高(P＜0.05);与T3时比较,两组T～T6时微透析液葡萄糖浓度和丙酮酸浓度升高,L/P比降低,T5、T6时乳酸浓度降低(P＜0.05).结论 七氟醚改善颅内动脉瘤夹闭术患者脑能量代谢的效果优于异丙酚.     

七氟醚和硝普钠控制性降压对患者一氧化氮、内皮素及氧自由基的影响

目的 探讨七氟醚和硝普钠(SNP)控制性降压对患者一氧化氮(NO)、内皮素(ET)和氧自由基的影响.方法 择期手术病人48例,年龄28～64岁,ASA Ⅰ或Ⅱ级,随机分为3组(n=16):七氟醚常压组(Ⅰ组)、七氟醚降压组(Ⅱ组)和SNP降压组(Ⅲ组).3组麻醉诱导后均吸入七氟醚1 MAC.手术开始后10 min,Ⅱ组吸入七氟醚浓度增加至3 MAC,Ⅲ组开始持续静脉输注0.01% SNP 2～5 μg·kg-1·min-1,使平均动脉压(MAP)快速降至基础值的60%-70%(55-73 mm Hg),再调整七氟醚呼气末浓度(1.87～2.54 MAC)和SNP输注速率(1.5～4 μg·ks-1·min-1)维持降压,降压40 min后,Ⅱ组七氟醚呼气末浓度降至0.8 MAC;Ⅲ组停止输注SNP,使血压很快升至降压前水平.分别于手术开始后10 min(降压前即刻,T0)、降压20 min(T1)、40 min(T2)和停止降压后20 min(T3)采集静脉血,测定血浆NO、ET、丙二醛(MDA)浓度及超氧化物歧化酶(SOD)活性.结果 与T0比较,Ⅰ组和Ⅱ组血浆NO浓度在T1～3时降低,Ⅲ组血浆NO浓度在T1,2时升高,Ⅲ组在T1,2时血浆ET浓度升高,3组在T1～3,时血浆MDA和SOD浓度均升高(P＜0.05或0.01);与Ⅰ组比较,Ⅱ组在T1,2时血浆NO浓度降低,Ⅲ组在T1～3时血浆NO浓度升高,Ⅲ组血浆ET浓度在T1～3时升高(P＜0.05),Ⅱ组各时点血浆NO浓度差异无统计学意义(P＞0.05);Ⅱ组在T1～3时血浆MDA和SOD水平升高(P＜0.05).结论 七氟醚控制性降压可降低患者血浆NO浓度,SNP控制性降压可升高血浆NO及ET浓度;七氟醚控制性降压及硝普钠控制性降压均可导致患者氧自由基生成增加,七氟醚控制性降压使氧自由基增加的程度更高.     

异氟醚控制性降压对颅内动脉瘤夹闭术血中S100B含量的影响

目的　测定颅内动脉瘤夹闭前后血中S1 0 0B蛋白含量 ,研究异氟醚控制性降压对脑功能的影响。方法　择期颅内动脉瘤夹闭术病人 30例 ,ASAⅠ～Ⅱ级 ,随机分为两组 :异氟醚降压组 (n=1 5 )和异氟醚非降压组 (n =1 5 )。非降压组术中吸入 1MAC异氟醚维持麻醉。降压组行异氟醚控制性降压 ,平均动脉压下降幅度 30 %～ 4 0 % ,夹闭动脉瘤后降低异氟醚吸入浓度 ,终止降压。分别于切皮前、动脉瘤夹闭后即刻、2、4h、术后第 1、2天取血测定S1 0 0B蛋白含量 ,并于术后 1周随访病人 ,记录有无术后神经系统并发症。结果　 (1 )异氟醚降压后 30min平均动脉压由诱导前的 (95 2± 1 2 3)mmHg降至 (5 8 8± 5 4 )mmHg ,停止降压后 30min血压回升至 (75 1± 8 3)mmHg。降压后外周血管阻力及心肌收缩加速度下降 ,但心率及心输出量均无显著性变化 ;(2 )异氟醚降压组与非降压组间同一时间点血中S1 0 0B蛋白浓度无明显差异。降压组术后第 1天及第 2天血中S1 0 0B蛋白浓度均显著升高 (F =2 94 4 ,P =0 0 1 8)。结论　在颅内动脉瘤夹闭术中应用异氟醚控制性降压可能加重了术后脑损伤 ,不利于病人围麻醉期脑功能的保护     

Histochemical and contractile properties of striated muscles of urethra and levator ani of dogs and sheep

AIMS: To understand their possible importance in long- and short-term control of continence, some properties of the striated muscles of the urethra and pelvic floor (levator ani) of dogs and sheep were investigated, especially fiber types and contractile characteristics. MATERIALS AND METHODS: Striated muscles of urethra and levator ani of 29 male and 6 female dogs and 11 male and 6 female sheep were removed and cut into strips. Some strips were frozen and stained for ATPase at pH 9.4 and 4.3 for fiber typing; others were set up in an organ bath to study contractile responses to nerve stimulation. RESULTS: All muscles contained both type I (slow) and type II fibers, ranging from 97% type II in female greyhound urethra to 60% in female sheep levator ani. For each muscle, there were fewer type II muscles in sheep than in dog. The diameters of the urethral fibers were about 60% of the levator ani in dogs and 34% in sheep. Contraction of the urethral muscle was faster than for levator ani and declined to about 80% of the peak, 500 msec after the beginning of stimulation at 20 Hz. The levator ani contraction rose to a steady level as long as stimulation continued. CONCLUSIONS: Both the levator ani and urethral striated muscles contain slow and fast fiber types. The levator ani muscles are capable of sustained contraction with rapid onset which will produce long-term closure of the urethra. The circular urethral muscle contraction was faster but less well maintained.     

Incorporation and release of85Sr and14C-proline-hydroxyproline in mineral and collagen of bone and incisor teeth of growing rats

The extent to which exchange and reutilization processes of mineral tracers affect skeletal mineral accretion and resorption measurements was evaluated by comparing the rates of appearance and disappearance of⁸⁵Sr and¹⁴C-proline-hydroxyproline in bones and teeth in growing rats for 12 days following simultaneous parenteral injection of these tracers. Expressions for the relative rates of collagen synthesis and breakdown, which unlike mineral metabolism are considered not to be complicated by exchange phenomena, were based on¹⁴C-proline conversion to¹⁴C-hydroxyproline; the specific activity of the latter was determined. Both the mineral and the collagen specific activities reflected the rates and patterns of growth of the samples assayed; rapid growth and a short interval of time between formation and resorption of tissue in themetaphyseal bone which contains the cartilagineous growth plate, slow growth and an interval of time between formation and resorption of tissue indiaphyseal bone and incisor teeth which is longer than the 12 days of the experiment. However, in metaphyseal bone the specific activity collagen/mineral ratio dropped by one half during the 4–12 day interval in contrast to diaphyseal bone and incisor teeth in which no change in this ratio was observed during this period of time. The data indicate that collagen in the metaphyseal growth zone is removed by resorption before it has become fully mineralized, and that exchange is a relatively unimportant factor in the long term kinetics of bone mineral.

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Zusammenfassung Das Ausmaß, bis zu welchem Austausch- und Wiederverwendungsprozesse der mineralen Tracer die Messungen des mineralen Skelett-Auf- und Abbaues beeinflussen können, wurde ausgewertet; zu diesem Zweck wurde die Geschwindigkeit des Auftretens und Verschwindens von⁸⁵Sr und von¹⁴C-Prolin-Hydroxyprolin in Knochen und Zähnen von wachsenden Ratten während der 12 auf die simultane parenterale Injektion dieser Tracer folgenden Tage verglichen.Der Ausdruck für die relative Geschwindigkeit des Kollagen-Auf- und Abbaues, bei welchem im Gegensatz zum Mineralmetabolismus kein Mitwirken des Austauschphänomens vermutet wird, basiert auf der Umwandlung von¹⁴C-Prolin zu¹⁴C-Hydroxyprolin; die spezifische Aktivität des letzteren wurde bestimmt.Aus der spezifischen Aktivität des Minerals sowie jener des Kollagens konnten die Geschwindigkeit und die Art des Wachstums der untersuchten Proben ersehen werden, d.h.schnelles Wachstum und ein kurzes Zeitintervall zwischen Bildung und Resorption des Gewebes imKnochen der Metaphyse, die auch die knorpelige Wachstumsplatte enthält, und andererseitslangsames Wachstum und längeres Zeitintervall (länger als die 12 Tage des Experimentes) zwischen Bildung und Resorption des Gewebes imKnochen der Diaphyse und in den Schneidezähnen. Immerhin fiel die spezifische Aktivität des Kollagen/Mineral-Anteils im Knochen der Metaphyse während dem 4–12tägigen Zeitintervall auf die Hälfte, im Gegensatz zum Knochen der Diaphyse und der Schneidezähne, bei welchen während dieser Zeitspanne kein Unterschied in diesem Verhältnis beobachtet wurde.Diese Ergebnisse zeigen, daß Kollagen in der Wachstumszone der Metaphyse durch Resorption verschwindet, bevor es ganz mineralisiert ist, und daß der Austausch ein relativ unwichtiger Faktor in der Kinetik auf lange Sicht des Knochenminerals ist.

     

Instrumented ligamentotaxis and stabilization of compression and burst fractures of dorsolumbar and mid-lumbar spines

Background:

Controversy continues regarding the best treatment for compression and burst fractures. The axial distraction reduction utilizing the technique employing the long straight rod or curved short rod without derotation to reduce fracture are practised together with short segment posterolateral fusion (PLF). Effects of the early postoperative mobilization without posterolateral fusion on reduction maintenance and fracture consolidation were not evaluated so far. The present prospective study is designed to assess the effectiveness of i) reduction and restoration of sagittal alignment, ii) no posterolateral fusion on the reduced, fractured vertebral body and injured disc, iii) fracture consolidation and iv) the fate of the unfused cephalad and caudal injured motion segments of the fractured vertebra.

Materials and Methods:

The study includes 15 Denis burst and two Denis type D compression fractures between T₁₂ and L₃. The lordotic distraction technique was used for ligamentotaxis utilizing the contoured short rods and pedicle screw fixator. Three vertebrae including the fractured one were fixed. The patients after surgery were braced for ten weeks with activity restriction for 2-4 weeks. The patients were evaluated for change in vertebral body height, sagittal curve, reduction of retropulsion, improvement in neural deficit. The unfused motion segments, residual postoperative pain and bone and metal failure were also evaluated.

Results:

The preoperative and postreduction percentile vertebral heights at, zero (immediate postoperative), at three, six and 12 months followup were 62.4, 94.8, 94.6, 94.5 and 94.5%, respectively. The percentages of the intracanal fragment retropulsion at preoperative, and postoperative at zero, 3, 6 and 12 months followup were 59.0, 36.2,, 36.0, 32.3, and 13.6% respectively.The preoperative and postreduction percentile loss of the canal dimension and at zero, three, six and 12 months were 52.1, 45.0, 44.0, 41.0 and 29% respectively suggesting that the under-reduced fragment was being resorbed gradually by a remodeling process. The mean initial kyphosis of 33° became mean 2° immediately after reduction and mean 3° at the final followup. The fractured vertebral bodies consolidated in an average period of ten weeks (range 8-14 weeks). The restored disc heights were relatively well maintained throughout the observation period. All paraparetic patients recovered neurologically. There were no postoperative complications.

Conclusion:

Instrument-aided ligamentotaxis for compression and burst fractures utilizing the short contoured rod derotation technique and the instrumented stabilization of the fractured spine are found to be effective procedures which contribute to the fractured vertebral body consolidation without recollapse and maintain the motion segment function.     

Principles and Practice of Hemofiltration and Hemodiafiltration

There is growing interest in the convective dialysis therapies, hemofiltration (HF) and hemodiafiltration (HDF). Both require dialysis membranes which are highly permeable to solutes as well as fluid, and in both cases large volumes of ultrafiltration are the condition for convective transport. In HDF the convection is combined with diffusion, and as a consequence, maximum clearance over the entire molecular weight spectrum is achieved. Optimal forms of HDF provide urea clearance 10–15% higher than the corresponding diffusive mode. The larger the solute, the greater is the impact of convection, and β₂-microglobulin (β₂m) levels may be up to 70% reduced. Traditional postdilution HF provides high clearance of medium sized and large molecules. Satisfactory clearance of small solutes requires blood flows in excess of 500 ml/min. With access to practically unlimited volumes of substitution solution through on-line ultrafiltration, predilution HF can now be used. This increases the clearance of small solutes to an acceptable range. For HDF as well as HF, large patient populations consistently treated for longer periods of time are needed to make valid outcome comparisons with other therapies.     

Recognition and management of phaeochromocytoma and paraganglioma

Phaeochromocytomas and paragangliomas (PPGL) are catecholamine-secreting neuroendocrine tumours arising from the chromaffin cells in the adrenal medulla. These tumours may be identified incidentally, as part of a work-up for multiple endocrine neoplasia or following haemodynamic surges during unrelated procedures. Advances in perioperative management and improved management of intraoperative haemodynamic instability have significantly reduced surgical mortality from around 40% to less than 3%. Surgery is the definitive treatment in most cases and laparoscopic resection where possible is associated with improved outcomes. Anaesthetic management of PPGL cases represents a unique haemodynamic challenge both before and after tumour resection. In this article we describe the physiology of these tumours, their diagnosis, preoperative optimization methods, intraoperative anaesthetic management and management of postoperative complications.     

骨折不愈合与延迟愈合的成因与治疗

目的探讨骨折不愈合与延迟愈合的成因、报肯治疗的方法与设果。方法对1990年7月～2004年12月间收治的107例骨折不愈台、54例骨折延迟愈合2例先天性胫骨骨不连进行回顾性研究，分析原因，随访治疗结果。18例延迟愈合行保守治疗，本组其他145例行手术治疗，结果除2例先天性胫骨骨不连外，其余161例的成因中均有医源性因素。10例失去随访，153例平均随访17（6-28）个月，骨折均获骨性连接，愈合时间平均10（6-14）个月，肢体功能恢复良好，结论医源性技术缺陷是骨折不愈合与延迟愈合的主要原因，针对各种不同因素进行合理治疗可获得满意效果。     

Physiology and pharmacology of nausea and vomiting

Nausea and vomiting are both very unpleasant experiences. The physiology is poorly understood; however, understanding what we do know is key to tailoring a preventative or therapeutic antiemetic regime. There are two key sites in the central nervous system implicated in the organization of the vomiting reflex: the vomiting centre and the chemoreceptor trigger zone. There are five key neurotransmitters involved in afferent feedback to these areas. These are histamine (H₁ receptors), dopamine (D₂), serotonin (5-HT₃), acetyl choline (muscarinic) and neurokinin (substance P). Postoperative nausea and vomiting will occur in around one-third of elective patients who have no prophylaxis. This can result in many detrimental effects including patient dissatisfaction, unplanned admission and prolonged recovery. It is therefore essential that clinicians understand how they can prevent and treat nausea and vomiting using either a single agent or a combination of antiemetics to target relevant receptors. Commonly used drugs include antihistamines, dopamine antagonists, serotonin antagonists and steroids. More novel agents are being developed such as aprepitant, a neurokinin receptor antagonist, palonosetron, a 5HT₃ receptor antagonist and nabilone, a synthetic cannabinoid.     

Physiology and pharmacology of nausea and vomiting

Nausea and vomiting are both very unpleasant experiences. The physiology is poorly understood; however, understanding what we do know is key to tailoring a preventative or therapeutic antiemetic regime. There are two key sites in the central nervous system implicated in the organization of the vomiting reflex: the vomiting centre and the chemoreceptor trigger zone. There are five key neurotransmitters involved in afferent feedback to these areas. These are histamine (H₁ receptors), dopamine (D₂), serotonin (5-HT₃), acetyl choline (muscarinic) and neurokinin (substance P). Postoperative nausea and vomiting will occur in around one-third of elective patients who have no prophylaxis. This can result in many detrimental effects including patient dissatisfaction, unplanned admission and prolonged recovery. It is therefore essential that clinicians understand how they can prevent and treat nausea and vomiting using either a single agent or a combination of antiemetics to target relevant receptors. Commonly used drugs include antihistamines, dopamine antagonists, serotonin antagonists and steroids. More novel agents are being developed such as aprepitant, a neurokinin receptor antagonist, palonosetron, a 5HT₃ receptor antagonist, and nabilone, a synthetic cannabinoid.