七氟醚对内毒素诱导大鼠肺组织氧化应激反应的影响

目的 探讨七氟醚对内毒素（LPS）诱导大鼠肺组织氧化应激反应的影响。方法Wistar大鼠48只，体重200-290g，随机分为4组（n=12）：对照组（C组）、LPS组（L组）、1．0MAC七氟醚组（S1L组）和1．5MAC七氟醚组（S2L组）。各组大鼠腹腔注射异戊巴比妥钠100mg／kg，麻醉后机械通气。维持呼气末二氧化碳分压在35～45mmHg。L组股静脉注射LPS5mg／kg，C组给予生理盐水1．2ml，S1L组、S2L组注射LPS后分别吸入1．0MAC、1．5MAC七氟醚4h。吸入七氟醚后4h处死大鼠，测定肺组织超氧化物超歧化酶（SOD）、丙二醛（MDA）、一氧化氮（NO）、总一氧化氮合酶（tNOS）水平、诱导型一氧化氮合酶（iNOS）活性及iNOS mRNA、蛋白表达。结果 与C组比较，L组肺组织SOD活性下降，MDA、NO、tNOS水平、iNOS活性及iNOS mRNA及蛋白表达均升高（P〈0．01）；与L组比较，S1L组、S2L组肺组织SOD活性升高，MDA、NO、tNOS水平及iNOS mRNA及蛋白表达降低（P〈0．05）；S1L组与S2L组上述各项指标比较差异无统计学意义（P〉0．05）。结论 吸入1．0MAC和1．5MAC七氟醚4h可减轻LPS诱导肺组织氧化应激反应。     

不同浓度异氟醚对大鼠肺脏的影响

目的 观察吸入不同浓度异氟醚诱发大鼠急性肺损伤的作用。方法 90只Wistar大鼠随机分为三组,每组30只正常对照组(C组)、0.6％异氟醚吸入组(0.6％Iso组)和1.4％异氟醚吸人组(1.4％Iso组)。每组分别在吸入异氟醚2、4和8h处死10只大鼠。检测支气管肺泡灌洗液中中性粒细胞比值及蛋白浓度、肺含水量,用Western blot检测支气管肺泡灌洗液及血清中表面活性蛋白A(SP-A)的含量;光镜下观察肺组织病理形态的改变。结果 三组大鼠吸入异氟醚后各时点肺含水量差异无显著性(P>0.05)。1.4％lso组在吸入异氟醚后8 hBALF中蛋白浓度、中性粒细胞比值均高于C组和0.6％Iso组(P<0.05)。与C组比较,1.4％Iso组大鼠吸入异氟醚后8 h BALF中SP-A浓度降低,而血清中SP-A浓度升高(P<0.05或0.01)。1.4％Iso组大鼠在吸入异氟醚后8 h肺毛细胞血管轻度扩张、充血、水肿,部分肺泡内中性粒细胞浸润。结论 长时间(8 h)吸入临床相关浓度的异氟醚可减弱肺泡上皮功能,其作用与吸入浓度和时间有关。     

七氟醚对在体大鼠肺缺血-再灌注损伤的影响

目的研究七氟醚对在体大鼠肺缺血-再灌注(I-R)损伤的影响。方法40只Wistar大鼠建立在体大鼠肺I-R模型,随机分为四组,每组10只:A组,假手术组,开胸后机械通气120 min;B组,I-R组,阻断左肺门60 min,开放再通气60 min;C组,七氟醚加I-R组,缺血前吸入1 MAC七氟醚30 min,开放再通气同时吸入1 MAC七氟醚60 min;D组,七氟醚组,持续吸入1 MAC七氟醚120min。观察各组实验结束时肺组织的湿/干重比(W/D)、肺丙二醛(MDA)、超氧化物歧化酶(SOD)和肺组织病理学的改变。结果B组及C组肺W/D较A组和D组显著升高(P<0.01,P<0.05),SOD含量显著低于A组和D组(P<0.05);B组肺MDA含量较A组和D组显著升高(P<0.01),C组肺MDA含量较B组低(P<0.05);C组肺W/D、肺MDA显著低于B组(P<0.05),SOD高于B组(P<0.05);病理切片见B组、C组部分肺泡结构破坏,肺泡间隔增宽,肺泡腔内水肿并有出血,以B组改变较为严重,炎症积分显著高于C组(P<0.01)。结论七氟醚对在体大鼠肺I-R损伤有一定的保护作用。     

异氟醚对大鼠肺缺血再灌注损伤的保护作用

目的 探讨异氟醚对大鼠肺缺血再灌注损伤的保护作用。方法 120只SD雄性大鼠，随机分成4组（n=30）：假手术组（S组）、缺血再灌注组（IR组）、异氟醚-缺血再灌注组（ISO-IR组）和异氟醚组（ISO-S组）。IR组、ISO-IR组建立肺缺血再灌注模型，ISO-IR组吸入1MAC异氟醚30min时行肺缺血再灌注，ISO-S组吸入1MAC异氟醚，不进行肺缺血再灌注。分别在缺血45min、再灌注30、60、120min处死6只大鼠，测定肺组织湿干比（W／D）、髓过氧化物酶（MPO）活性、中性粒细胞（PMN）膜表面CD18和肺组织ICAM-1mRNA表达、支气管肺泡灌洗液（BALF）中自细胞计数、沉渣白细胞分类和总蛋白（TP）浓度，并进行肺组织病理学检查。结果 再灌注期间IR组肺组织W／D、MPO活性、CDl8和ICAM-1mRNA表达、BALF中PMN百分比、TP浓度及PMN膜表面CD18表达均升高。而异氟醚预先给药减弱了缺血再灌注诱导的上述指标的升高。肺组织病理学检查显示异氟醚预先给药减轻了肺缺血再灌注损伤。结论 通过抑制PMN浸润和肺组织ICAM-1mRNA及CD18表达上调，缺血前吸入异氟醚对肺缺血再灌注损伤有一定的保护作用。     

吸入不同浓度七氟醚麻醉对大鼠肺组织炎性反应的影响

目的 评价吸入不同浓度七氟醚麻醉对大鼠肺组织炎性反应的影响.方法 成年Wistar大鼠120只,雌雄不拘,体重200～250 g,随机分为4组:正常对照组(C组,n=12)、氧气组(O组,n=36)、1.5%七氟醚组(S1组,n=36)和3%七氟醚组(S2组,n=36).除C组外,其余各组根据吸入气体时间不同分为3个亚组(n=12),O组的3个亚组分别为4 h亚组、8 h亚组和10 h亚组;S1组和S2组的3个亚组分别为4 h亚组、8 h亚组和恢复亚组.C组仅吸入空气,O组吸入40% O2,S1组和S2组的4 h亚组和8 h亚组分别吸入40%O2+1.5%七氟醚或40%O2+3.0%七氟醚,恢复亚组吸入40%O2+1.5%或40%O2+3.0%七氟醚8 h后停止吸入七氟醚,然后吸入40%O2 2 h.于停止吸入气体时处死大鼠,测定支气管肺泡灌洗液(BALF)中TNF-α浓度;取肺组织,测定TNF-α mRNA表达和髓过氧化物酶(MPO)活性.结果 与C组比较,其他各组TNF-α浓度、TNF-α mRNA表达和MPO差异无统计学意义(P＞0.05);与O组的各亚组比较,S1组和S2组的各亚组上述指标差异无统计学意义(P＞0.05);S1组和S2组的各亚组间上述指标差异无统计学意义(P＞0.05).结论 吸入1.5%或3.0%七氟醚麻醉不诱发大鼠肺组织炎性反应.     

幼猪机械通气中异氟醚或七氟醚混合一氧化氮吸入的安全性

目的研究吸入异氟醚或七氟醚混合一氧化氮(NO)在幼猪机械通气中的安全性。方法36头幼猪随机分为6组:Ⅰ组(对照组):单纯机械通气;Ⅱ组(NO组):吸入20ppmNO;Ⅲ组(异氟醚组):吸入1.3MAC异氟醚;Ⅳ组(异氟醚 NO组):吸入1.3MAC异氟醚及20ppmNO;Ⅴ组(七氟醚组)吸入1.3MAC七氟醚;Ⅵ组(七氟醚 NO组)吸入1.3MAC七氟醚及20ppmNO。用麻醉机行间歇正压通气4h,测定各组机械通气前、机械通气1、2、3、4h(T0、T1、T2、T3、T4)的呼吸频率(RR)、呼吸系统总顺应性(Crs)、气道压力(Paw)、潮气量(VT)、分钟通气量(MV)以及呼末二氧化碳分压(PETCO2);测定T0、T2、T4时点动脉血高铁血红蛋白(MetHb)和亚硝酸根(NO2-/NO3-)水平;处死动物后比较各组肺组织湿/干重比、支气管肺泡灌洗液(BALF)中饱和磷脂/总磷脂(DSPC/TPL)及饱和磷脂,总蛋白(DSPC/TP)、肺表面张力和白细胞计数,并行肺组织损伤评分。结果Ⅲ、Ⅳ、Ⅴ、Ⅵ组BALF中DSPC/TP及肺表面张力较Ⅰ组下降(P<0.05),通气结束时Crs较通气前下降(P<0.05),而Ⅱ组无显著性变化(P>0.05);与通气前比较,各组通气结束时MetHb与:NO2-/NO3-水平无变化,各组BALF中白细胞计数、肺组织损伤评分、肺泡扩张度和湿/干重比之间比较差异无统计学意义。结论1.3MAC异氟醚或七氟醚混合20ppmNO吸入可以安全用     

异氟醚对家兔肺缺血-再灌注损伤的影响

目的 研究异氟醚对体家兔肺缺血－再灌注（I－R）损伤的影响。方法 32只新西兰家兔根据Eppinger模型加以改进,建立在体兔肺缺血再灌注模型,随机分四组（n＝8）,A组：假手术组,开胸后维持通气120min。B组：缺血再灌注组,阻断左肺门60min,开放再通气60min。C组：异氟醚＋缺血再灌主组,缺血前吸入1MAC异氟醚30min,开放再通气时也吸入1MAC异氟醚。D组：异氟醚组,持续吸入1MAC异氟醚120min,观察各组实验结束时肺湿－干重比（W／D）,肺内二醛含量（MDA）和肺组织学改变以及术中血流动力学的改变。结果 B组及C组W／D,肺MDA含量均较A、D两组显著增高,（P＜0．05）,且病理切片显示,部分肺泡结构破坏,肺泡间隔增宽,肺泡腔水肿并有白细胞渗出,但B组改变明显严重,且B组W／D,肺MDA含量也明显高于C组（P＜0．05）,血液动力学基本维持正常。结论 异氟醚在体家兔肺I－R损伤有一定的保护作用。     

吸入不同浓度异氟醚对大鼠肺脏磷脂合成的影响

目的探讨吸入不同浓度异氟醚(Iso)对正常大鼠肺脏磷脂酰胆碱(PC)合成代谢的影响。方法78只Wistar大鼠随机取出6只设为空白组(E组),吸入空气。剩余大鼠随机均分为四组,每组又分为吸入4、8h和吸入8h停药2h亚组,每亚组6只。采用高效液相色谱法(HPLC法)测定支气管肺泡灌洗液(BALF)中PC浓度,RT-PCR和蛋白质免疫印迹法(WesternBlot)分别检测肺组织磷酸胆碱二胞苷酰基转移酶(CCT)基因及其蛋白的表达。结果各组间肺组织CCTmRNA和匀浆中CCT蛋白的表达差异无统计学意义。B2组、C2组BALF中PC含量及肺组织微粒体CCT蛋白的表达量均低于E组和B1组、C1组(P<0.05),停药后2h恢复。吸入Iso8h时,B2组、C2组BALF中PC含量及肺组织微粒体CCT蛋白的表达量均低于D2组(P<0.05),同时C2组低于A2组(P<0.05)。结论长时间吸入较高浓度的异氟醚可降低大鼠正常肺脏磷脂合成水平,其机制可能与CCT活性降低有关。     

七氟醚对内毒素致急性肺损伤鼠肺泡毛细血管膜通透性的影响

目的　探讨七氟醚对内毒素致急性肺损伤鼠肺泡毛细血管膜通透性和肺泡灌洗液内炎性细胞的影响。方法　 4 8只Wistar大鼠 ,麻醉后静注伊万斯蓝 5 0mg/kg后 ,随机分为 4组 ,每组 12只。对照组 :股静脉注射生理盐水 1 2ml后机械通气 4h ;内毒素组 :股静脉注射内毒素 5mg/kg后机械通气 4h ;七氟醚 1L组和七氟醚 2L组 :股静脉注射内毒素 5mg/kg后机械通气 ,分别吸入肺泡气最低有效浓度 (MAC)为 1 0和 1 5的七氟醚 4h。 4h后取肺组织测定 :病理形态学积分 ,肺湿 /干重比 ,肺水含量 ,肺通透指数 ,伊万斯蓝含量和肺泡灌洗液内炎性细胞总数及百分比。结果　七氟醚1L组肺通透指数、伊万斯蓝含量、病理形态学积分分别由 4 6 8± 0 82 ,( 112 2 1± 11 4 4 )ng/mg ,9 17± 0 90下降到 3 98± 0 5 0 ,( 92 85± 11 80 )ng/mg ,7 5 0± 0 96 ;七氟醚 2L组下降到 3 91±0 34,( 96 33± 8 79)ng/mg ,7 6 7± 0 75。结论　 1 0和 1 5MAC七氟醚可降低内毒素所致急性肺损伤肺泡毛细血管膜通透性 ,使肺组织病理损伤减轻     

七氟醚减轻大鼠呼吸机相关性肺损伤

目的 探讨七氟醚对大鼠呼吸机相关性肺损伤(VILI)的影响并探讨其可能机制。方法 健康SPF级雄性SD大鼠36只,6～8周龄,体重220～280 g。随机分为三组：对照组(C组)、VILI组(V组)和七氟醚组(S组),每组12只。大鼠给予1%戊巴比妥钠40 mg/kg麻醉后行气管切开插管术,C组自主呼吸4 h, V组和S组插管后机械通气4 h, S组机械通气期间吸入2%七氟醚4 h。通气参数：V_T 20 ml/kg, RR 80次/分,I∶E 1∶1,FiO₂ 21%,PEEP 0 cmH₂O。机械通气结束时采集股动脉血测定PaO₂。处死大鼠,取肺组织和支气管肺泡灌洗液(BALF),计算肺组织湿/干重比值(W/D),采用ELISA法检测BALF中白细胞介素(IL)-1β、IL-18浓度,二氯荧光黄双乙酸盐法检测BALF中肺泡巨噬细胞活性氧(ROS)水平,Western blot法及qRT-PCR法检测肺组织NF-E2相关因子2(Nrf2)、NLRP3、凋亡相关斑点样蛋白(ASC)、caspase-1...     

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.