一期后路病灶清除植骨融合内固定矫形治疗伴后凸畸形的儿童胸腰段脊柱结核的临床初步报告

[目的]探讨经后路一期病灶清除、植骨融合内固定矫形治疗伴后凸畸形的儿童胸腰段脊柱结核的可行性及疗效.[方法]7例胸腰段脊柱结核患儿,均伴有后凸畸形.其中男5例,女2例;年龄9～12岁.术前脊柱后凸角为35°～45°,平均37.9°.Frankel分级:B级2例,C级3例,D级2例.采用经后路一期病灶清除、植骨融合加钉棒系统矫形固定治疗.[结果]术后随访27～42个月,平均34个月.切口均一期愈合,无1例结核复发.Frankel分级:4例恢复2级,3例恢复1级.术后后凸角为2°～9°,较术前明显改善,最后随访时后凸角为2°～12°,较术后无明显丢失.术后3个月血沉均恢复正常;所有患儿均获得满意的植骨融合.[结论]一期后路病灶清除、后方植骨内固定矫形手术治疗伴后凸畸形的儿童胸腰段脊柱结核是矫正后凸畸形和预防晚期后凸畸形发生的有效方法.     

分期后路短节段固定前路病灶清除植骨融合治疗儿童下腰椎结核

目的:探讨一期后路钉钩棒短节段内固定、二期前路病灶清除植骨融合术治疗儿童下腰椎结核的手术方法及疗效。方法:2004年5月～2008年2月共收治儿童下腰椎结核患者9例,其中男5例,女4例,年龄5～11岁,平均7.8岁。术前腰椎局部前凸角-18°～4°,平均-8.6°±7.4°。均无明显的腰椎后凸畸形。病变累及一个椎体1例,累及2个椎体7例,累及3个椎体1例。术前神经功能Frankel分级:B级1例,C级3例,D级5例。均采用一期行后路短节段内固定,二期行前路病灶清除植骨融合手术治疗。观察比较术前、术后及末次随访时患者局部前凸角,评估植骨融合情况及神经功能恢复情况。结果:所有病例均获随访,随访时间30～53个月,平均41.0±7.8个月。术后腰椎局部前凸角5°～11°,平均8.8°±1.7°,较术前明显改善(P<0.05)。末次随访时腰椎局部前凸角为5°～10°,平均7.3°±1.7°,较术后无明显角度丢失(P>0.05)。1例末次随访时神经功能Frankel分级仍为D级,余患者神经功能均恢复至正常。随访期间无内固定松动及断裂,植骨获得满意融合,无结核复发。结论:对于无明显后凸畸形的儿童下腰椎结核患者,一期后路钉钩棒系统短节段内固定、二期前路病灶清除植骨融合术,是一种安全有效的治疗方法。     

前路病灶清除植骨内固定治疗胸腰椎结核

目的探讨胸腰椎结核前路病灶清除植骨内固定手术治疗的效果。方法本组104例采用前路病灶清除植骨内固定治疗脊柱结核,病变位于胸椎30例、胸腰椎24例、腰椎50例,术前有后凸成角畸形38°±19°。手术前后配合正规化疗,根据X线片观察脊柱融合时间,手术前后后凸角度变化以及按照Frankel分级的神经功能变化。结果全部病例伤口均一期愈合,未出现严重并发症。随访时间10～48个月,植骨界面骨性融合时间平均5个月。后凸平均矫正度数为18°±5°,22例术前伴有神经损害症状者Frankel分级平均提高2级。结论脊柱前路一期病灶清除植骨内固定治疗胸腰椎结核具有能矫正后凸成角畸形、预防畸形复发、术后患者能早期离床活动等优点,治疗效果满意。     

Ⅰ期手术经后路病灶清除内固定治疗儿童胸椎结核

目的:探讨Ⅰ期手术经后路结核病灶清除植骨融合内固定治疗儿童胸椎结核的效果.方法:2005年6月至2010年12月采用病灶清除植骨融合内固定治疗儿童胸椎结核9例,其中男7例,女2例;年龄3～12岁,平均7岁;病史3个月～1年,平均6个月.患儿均有不同程度胸背痛、肋间神经痛以及脊柱后凸畸形,同时伴有低热、盗汗、消瘦等全身症状.术前X线片、CT、MRI检查提示病变部位多发生于T4-T9节段.胸段后凸角35°～72°,平均48.2°.术前脊髓功能ASIA分级:B级2例,C级5例,D级2例.术后定期复查X线片了解后凸角变化和椎间植骨融合情况,采用ASIA分级评定术后脊髓功能恢复情况.结果:术中无大血管或脊髓损伤,术后随访16～38个月,平均24个月.所有患儿结核症状消失,无结核复发、切口感染、窦道形成或内固定失败等并发症,复查血沉正常.术后4～8个月复查X线片提示椎间植骨均获骨性愈合,内固定位置正常.最后随访后凸角12°～30°,平均19.5°,脊髓功能ASIA分级:C级2例,D级2例,E级5例.脊髓功能均有不同程度改善.结论:Ⅰ期经后路清除胸椎结核病灶彻底,椎管减压可靠,矫形效果显著,行自体或同种异体骨植骨钉棒系统内固定可有效重建胸段脊柱的稳定性.     

后路椎弓根螺钉内固定联合前路病灶清除植骨融合治疗胸腰段脊柱结核

目的：探讨一期前路病灶清除、自体骨椎间植骨融合、后路椎弓根螺钉固定治疗胸腰椎结核的临床疗效。方法：2002年2月至2007年3月,共收治脊柱结核患者21例,其中男13例,女8例;平均年龄45.3岁。病变部位为胸腰段,2个椎体3例,3个椎体17例,4个椎体1例,皆有后凸畸形,平均Cobb角（28.0±9.7）°。术前Frankel脊髓功能分级：B级3例,C级5例,D级1例,E级12例。术前应用异烟肼、利福平、乙胺丁醇、吡嗪酰胺抗痨及全身支持治疗,手术采用后路椎弓根钉棒固定、前路病灶清除、前后路植骨融合术,术后继续化疗9～12个月。术后随访,观察脊髓功能改善情况,根据术前、术后X线片分析植骨融合情况及脊柱Cobb角并进行统计学分析。结果：切口均Ⅰ期愈合,随访1～6年,平均2.5年,末次随访时平均Cobb角（9.8±3.3）°,平均矫正17.2°,术前、术后比较,P〈0.01,植骨均融合。Frankel脊髓功能分级：C级1例,D级3例,E级17例。结论：胸腰段脊柱结核经后路椎弓根螺钉内固定、前路病灶清除、植骨融合,可有效纠正脊柱后凸畸形,重建脊柱稳定性,获得良好的骨性愈合。     

一期前路手术内固定治疗脊柱结核

目的:总结一期前路病灶清除、椎体间植骨及前路内固定治疗脊柱结核的临床疗效,探讨一期重建脊柱稳定性的必要性和安全性。方法:自2000年5月至2003年1月共收治21例脊柱结核患者,采用一期前路病灶清除、椎体间植骨及前路内固定治疗,其中颈椎2例、胸椎6例、胸腰段5例、腰椎8例。平均受累椎体数为2.6个。结果:经平均17个月随访,所有患者均临床痊愈,无伤口感染或窦道形成,植骨均完全融合,融合时间平均为3.6个月。术前后凸畸形角度为41.1°±15.6°,术后为13.5°±8.3°,平均17个月随访时为15.9°±6.7°。后凸畸形矫正角度平均为27.6°±9.2°,后期矫正度丢失为2.4°±3.3°。结论:一期前路手术内固定治疗脊柱结核能有效清除病灶、矫正后凸畸形、早期重建脊柱的稳定性及促进椎体间植骨的融合,是一种安全有效的治疗方法。     

一期后路病灶清除楔形截骨联合椎体间颗粒骨植骨融合术治疗伴严重后凸畸形的活动期胸腰椎结核

目的探讨一期后路病灶清除楔形截骨联合椎体间颗粒骨植骨融合术治疗伴严重后凸畸形的活动期胸腰椎结核的临床疗效。方法回顾性分析在山西医科大学第二医院接受一期后路病灶清除楔形截骨联合椎体间颗粒骨植骨融合术治疗的30例胸腰椎结核患者的临床资料。术前及末次随访时采用疼痛视觉模拟量表(VAS)评分评估疼痛程度,采用美国脊髓损伤协会(ASIA)分级评估脊髓损伤程度;术后每3个月行X线复查,评估骨融合情况和后凸畸形矫正情况;末次随访时采用Kirkaldy-Willis功能评分评估综合疗效。结果所有手术顺利完成,所有患者随访(24±5)个月,骨融合时间为(6.3±2.3)个月,融合率为100%。ASIA分级术前B级1例、C级2例术后恢复至D级;术前D级14例,术后12例恢复至E级,2例仍为D级;术前E级13例,术后仍为E级。后凸Cobb角术前为40.1°±8.1°,术后即刻为12.0°±7.0°,末次随访时为15.1°±6.9°,随访期间矫正角度丢失3.1°±1.4°,末次随访时后凸Cobb角与术前相比差异有统计学意义(P<0.05)。根据Kirkaldy-Willis功能评分标准,末次随访时综合疗效优22例、良6例、可2例,总优良率为93.33%。结论一期后路病灶清除楔形截骨联合椎体间颗粒骨植骨融合术治疗伴严重后凸畸形的活动期胸腰椎结核安全有效,但尚需更多的研究来验证其疗效,并得到确切的手术适应证。     

陈旧结核性脊柱后凸的后路手术治疗

目的 观察后路截骨矫形手术治疗陈旧结核性脊柱后凸的临床效果.方法 自2004年6月至2008年12月采用后路截骨矫形固定手术治疗31例陈旧结核性脊柱后凸患者,其中男性12例,女性19例,年龄13 ～56岁,平均33.4岁.手术方式包括后路经后凸顶点(椎弓根或椎间隙)截骨+闭合矫形或前方撑开-后方闭合矫形和后凸融合节段切除截骨,双轴旋转矫形和前柱重建.观察手术前后的后凸角度、腰椎前凸角和脊柱矢状位的平衡状况.同时于术前和随访时应用Frankel分级评定下肢神经功能,应用Oswestry功能障碍指数(ODI)评价患者生活质量.用患者满意指数(PSI)评价手术满意度.结果 术前平均后凸角度为94°±27°,平均腰椎前凸角为71°±20°,脊柱矢状位力线平均为(-15 ±44)mm.术后1周平均后凸角度改善为26°±11°,平均改善率为71.4％.术后平均随访22.5个月,末次随访时平均后凸角度为28°±12°,平均改善率为70.0％;平均腰椎前凸角为46°±11°,平均改善率为35.1％.术后后凸角度和腰椎前凸角与术前相比,其差异均有统计学意义(t=16.3和8.1,P＜0.05).脊柱矢状位力线平均为(-4 ±22)mm,平均改善率为73.4％.术前患者Frankel分级为E级13例,D级13例,C级5例;末次随访时E级增加至20例,D级8例,C级3例.术前ODI评分平均为(13±12)分,末次随访时改善为(7±8)分,平均改善率为45.2％.PSI显示总满意率为90.3％.结论 根据陈旧结核性脊柱后凸畸形的严重程度选择合适的截骨矫形方式,可以获得较好的手术效果.     

术前短期化疗联合前路单钉棒系统治疗胸腰椎结核

背景：多数学者认为脊柱结核术前化疗至少需要4周,且大多选用接骨板或双钉棒系统作为前路手术的内固定材料。有关缩短术前化疗时间和选择更为简单内固定的研究甚少。目的：探讨术前短期化疗联合前路单钉棒系统治疗胸腰椎结核的临床疗效。方法：2007年6月至2009年12月,16例脊柱结核患者行HRES四联化疗1周后行前路单钉棒系统内固定术,术后常规抗结核治疗1年。观察术后和随访期间的一般情况及疼痛症状,记录Frankel脊髓损伤分级,通过X线片了解植骨融合及后凸畸形矫正情况。结果：术前抗结核治疗1周,患者一般状况无明显改善,自术后第3d起,患者一般状况开始改善。术后3例患者出现肋间神经痛,经治疗2周后2例缓解,其余患者均未出现明显的并发症。所有植骨均得到融合,融合时间为6～15个月,平均9个月;后凸畸形由15°～82°,平均42.0°±16.7°,矫正至3°～19°,平均9.7°±4.4°。术后2年随访后凸畸形为3°～23°,平均11.6°±5.3°。平均丢失1.9°。结论：术前短期化疗对手术疗效无明显影响,但能缩短患者术前承受痛苦的时间。前路单钉棒系统内固定治疗胸腰段脊柱结核可彻底清除病灶、充分减压,同时矫正畸形、有效重建脊柱稳定性,以防止神经损害进一步加重,可尝试应用于临床。     

一期前路病灶清除联合自体肋骨植骨融合内固定治疗胸椎结核

目的：分析一期前路病灶清除、自体肋骨椎间植骨融合前路内固定术治疗胸椎结核的临床效果。方法2003年6月～2008年5月手术治疗胸椎脊柱结核42例,男25例,女17例,均采用一期前路病灶清除、自体肋骨椎间植骨融合前路内固定术。根据术前、术后随访的X线片,分析植骨融合及脊柱后凸畸形矫正效果;采用Frankel分级、红细胞沉降率（ erythrocyte sedimentation rate, ESR）、C反应蛋白（ C-reactionprotein, CRP ）及视觉模拟量表（ visual analog scale, VAS）评分评估临床治疗效果。结果随访1～7年,平均50．8个月,42例患者均获骨性愈合,愈合时间3～7个月,平均4．5个月,无内固定松动、脱出及断裂;术前Cobb角平均19．8°,术后1周为3．7°,末次随访时为4．6°;Frankel分级,术前B级为3例,C级9例,D级20例,E级10例,末次随访时为D级6例,E级36例;VAS评分术前平均为8．2,术后1周为1．8,末次随访时为1．2。除2例患者术后出现疼痛,持续2个月后自行缓解外,无其他并发症。无复发结核感染出现。结论一期行前路病灶清除、自体肋骨椎间融合前路内固定术治疗胸椎结核,可有效矫正脊柱后凸畸形,重建脊柱稳定性,获得较好的临床效果。     

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.     

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.     

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.     

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.     

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.

     

动静脉穿刺网络课件的开发及其应用

目的:确保护理教学效果,提高教学水平。方法:应用多项信息技术将动静脉穿刺技术制作成教学网络课件,并用于临床教学。结果:该课件在本校园网上运行半年余,2000余人次对其进行访问,受到师生好评。结论:该课件能及时反映动静脉穿刺的最新研究进展及具体操作步骤和使用方法,实现护理教学的直观性和交互性,对护理教学和临床带教指导有一定的借鉴作用。     

Physiology and pharmacology of nausea and vomiting

The physiology of nausea and vomiting is poorly understood. The initiation of vomiting varies and may be due to motion, pregnancy, chemotherapy, gastric irritation or postoperative causes. Once initiated, vomiting occurs in two stages, retching and expulsion. The muscles responsible for this sequence of events are controlled by either a vomiting centre or a central pattern generator, probably in the area postrema and the nearby nucleus tractus solitarius. Drugs which induce vomiting include ipecacuanha, a gastric irritant, and apomorphine, a dopamine-receptor agonist. Opioid drugs also induce vomiting, but opioid antagonists are not useful to treat nausea and vomiting. Anti-emetic drugs consist of a variety of neurotransmitter antagonists and may act in the periphery, the central nervous system or both sites. The most important drugs are antagonists at muscarinic, dopamine D₂, 5-HT₃, histamine H₁ and neurokinin NK₁ receptors. These drugs are discussed with particular attention to post-operative nausea and vomiting (PONV).