短肠综合征

Statement: Short Bowel Syndrome and Intestinal Transplantation

This document presents the official recommendations of the American Gastroenterological Association (AGA) on Short Bowel

Syndrome. It was approved by the Clinical Practice Committee on August 5, 2002 and by the AGA Governing Board on November 1, 2002.

S

hort bowel syndrome (SBS) occurs when, after surgery

or congenitally, a patient is left with _200 cm of

functional small intestine. Absorption is related to the

amount of residual intestine; patients at greatest nutritional risk generally have a duodenostomy or a jejunoileal anastomosis with _35 cm of residual small intestine, jejunocolic or ileocolic anastomosis with _60 cm of residual small intestine, or an end jejunostomy with _115 cm of residual small intestine. Patients can be grouped into 2 distinct subgroups: those with colon in continuity and those without colon in continuity. In

patients with SBS, the colon becomes an important digestive organ.

Medical Therapy

The most important aspects of medical management of the patient with SBS are provision of adequate macro- and micronutrients and fluid to prevent energy

malnutrition, specific nutrient deficiencies and dehydration, and correction and prevention of acid-base disturbances. Glucose–polymer-based oral rehydration solutions (ORS) with 90–120 mEq/L sodium (Na) should be instituted to decrease dehydration and total parenteral nutrition (TPN) fluid requirements in patients with

residual jejunum ending in a jejunostomy. Several commercial ORS are available, or solutions can be formulated

by dissolving NaCl (2.5 g), KCl (1.5 g), Na2CO2 (2.5 g), and glucose (table sugar, 20 g) in 1 L water. Patients should avoid consumption of plain water and should be encouraged to drink ORS whenever they are thirsty. For

patients with residual colon in continuity, ORS may still be of value—provided sufficient Na is present in the diet; the amount of Na in the ORS may not be as critical. For patients with no remaining jejunum, who have residual ileum, the presence of glucose in the ORS is not critical because ileal water absorption is not affected by the presence of glucose.

Magnesium (Mg) deficiency may occur despite a normal serum concentration. It is prudent to measure 24-

hour urine Mg. However, Mg replacement is problematic and often requires intravenous infusion. Oral calcium (Ca) supplementation is recommended routinely (800– 1200 mg per day). Iron is absorbed in the duodenum and, in the absence of hemorrhage, is not routinely

required as a supplement. Phosphorus deficiency is rare; supplementation is rarely required.

Resection of the ileocecal valve may allow colonic bacteria to populate the small intestine, resulting in bacterial overgrowth. This may negatively impact on digestion and nutrient assimilation, because bacteria compete for nutrients with the enterocytes. Diagnosis of bacterial overgrowth may be more difficult using breath

tests because of rapid intestinal transit in SBS. Endoscopically obtained small bowel aspirate for culture may be

required. Treatment can be undertaken with oral metronidazole, tetracycline, or other antibiotics.

High-dose H2 antagonists and proton pump inhibitors reduce gastric fluid secretion, and fluid losses during the first 6 months post-enterectomy. Fluid losses usually require long-term control with anti-motility agents, such as loperamide hydrochloride or diphenoxylate (4–16 mg per day). If these are ineffective, especially in patients without colon in continuity or in patients with minimal residual jejunum or duodenum, use of codeine sulfate (15–60 mg two to three times a day) or tincture of opium may be necessary. Rarely, octreotide (100 _g SQ, three times a day, 30 minutes before meals) is required. It should be used only if fluid intravenous

requirements are _3 L daily because post-resection intestinal adaptation may be impaired and the risk for

cholelithiasis increased. There is insufficient evidence to recommend the use of bile acid supplements to decrease steatorrhea; and they may worsen diarrhea. Cholestyramine is not useful in patients with _100 cm of ileal

resection, and it may actually worsen steatorrhea because of the binding of bile salts.

Dietary Management

Typically, patients who have undergone massive

enterectomy require TPN, once hemodynamic stability has been achieved, for the first 7–10 days after surgery.

Nutritional therapy should be introduced gradually, converting to standard enteral formula as tolerated. The goal

is to provide patients with approximately 25–30 kcal/kg per day and 1.0–1.5 g/kg per day of protein. Standard

enteral formula is recommended. Nitrogen is the macronutrient least affected by diminished intestinal absorptive surface. Therefore, the utility of peptide-based diets in such patients is generally without merit. Oral intake should be encouraged. There is no value in separating liquids from solids in the diet or with high fat–low carbohydrate or low fat–high carbohydrate diets except for patients with colon in continuity, in whom soluble

fiber intake should be encouraged. Soluble fiber is fermented to short-chain fatty acids by colonic bacteria and

serve as an additional energy source. Small amounts of medium-chain triglycerides are absorbed by the colon and may be included in the diet as an additional energy source. Lactose-containing foods should not be restricted in the absence of confirmed lactase deficiency or significant proximal jejunal resection. Dietary oxalate should

be restricted in the diet in patients with residual colon in continuity. Oral Ca supplements also may be of value for the prevention of Ca-oxalate nephrolithiasis. Randomized, controlled trials have not shown glutamine and/or

growth hormone to improve intestinal absorption. Micronutrients, including water-soluble (B1, B2, B3, B6,

B12, biotin, folate, C) and fat-soluble (A, D, E, K)

vitamins, and trace elements (Zn, Se) often require supplementation (Table 1). Water-soluble vitamin deficiency is rare.

Parenteral Nutrition

Most patients will require TPN, at least initially. For the normally nourished patient, TPN should be supplied at 25–30 kcal/kg per day based on ideal body weight for adults, with greater levels of support for infants and children depending on age. Dextrose is a monohydrate, providing 3.4 kcal/mL. The maximum dextrose infusion rate should be 5–7 mg/kg/min. Blood

glucose should be monitored at least daily, optimally qid, and should be _180–200 mg/dL; the addition of regular insulin to the TPN solution may be required. If insulin is required, it should be added to the TPN bag at an initial dose of 0.1 U/g dextrose; subsequent adjustments should be made as necessary. Intravenous lipids

are generally used to provide 20%–30% of infused calories, although a greater percentage of lipid may be used in the patient with significant glucose intolerance or fluid management issues; 20% lipid emulsion is more calorically dense than dextrose. Generally, the percentage of lipid calories should be increased and the percentage of dextrose calories should be decreased if the amount of supplemental insulin required exceeds 0.2 U/g dextrose, although the serum triglyceride concentration should be kept _700–800 mg/dL, and optimally, _400 mg/dL. Protein is supplied in the form of free amino acids and should be supplied at 1.0–1.5 g/kg per day, based on ideal body weight for adults, with greater levels of support for infants and children depending on age.

Initially, TPN is infused continuously while postoperative complications are addressed and metabolic issues

stabilized. Attempts should be made, when appropriate, to wean patients who have sufficient absorptive capacity; maximal adaptation may take as long as 1–2 years. For patients who will require TPN at home, the infusion

should be compressed to overnight. Typically, this would be during a 10-hour period with an additional 30–60-

minute taper period; some patients with fluid management issues will be unable to tolerate this infusion rate.

Cycling to overnight infusion should be a gradual process. Once goal infusion volume has been determined

(e.g., 1.5, 2.0, 2.5, or 3.0 L for adults; with less volume for infants and children), the total volume should be infused over gradually decreasing time periods (e.g., compress by increments of 2–4 hours). TPN should be

Table 1. Vitamin and Mineral Supplements for Patients With Short Bowel Syndrome

Vitamin A 10,000–50,000 units dailya

Vitamin B12 300 _g subcutaneously monthly for those with terminal ileal resections or disease Vitamin C 200–500 mg

Vitamin D 1600 units DHT daily; may require 25-OHor 1,23 (OH2)-D3

Vitamin E 30 IU daily Vitamin K 10 mg weekly Calcium See text Magnesium See text Iron As needed

Selenium 60–100 _g daily

Zinc 220–440 mg daily (sulfate form) Bicarbonate As needed

NOTE. The table lists rough guidelines only. Vitamin and mineral supplementation must be monitored routinely and tailored to the individual patient, because relative absorption and requirements may vary.

aUse cautiously in patients with cholestatic liver disease.

1106 AMERICAN GASTROENTEROLOGICAL ASSOCIATION GASTROENTEROLOGY Vol. 124, No. 4

infused ideally via a single lumen catheter with its tip positioned in either the superior vena cava (SVC) or inferior vena cava (IVC) to decrease the risk of infection and thrombosis. Tunneled catheters, implantable ports, or percutaneously inserted central catheters (PICCs) should be used at home, although the experience with PICCs for _1 year at home is minimal. To qualify for Medicare reimbursement, home TPN must be required

for at least 3 months, fat malabsorption must be documented, and enteral feeding must have failed.

The patient’s home environment should be evaluated. A room, preferably the bedroom—definitely not a

―dirty‖ room, such as the kitchen or bathroom—should be identified for TPN to be set up prior to use. The

patient should be instructed to purchase a small refrigerator to be used solely for TPN storage. A local support group under the umbrella of the Oley Foundation (1- 800-776-OLEY) should be contacted. Transition from hospital to home may be smoother if the patient has another patient contact who previously has undergone the same process. The patient should undergo some

education about TPN prior to hospital discharge, including the indications for TPN, basic instruction on getting their solutions ready for use (they will need to add their vitamins, insulin, and H2 blockers if prescribed, and

flush catheter), catheter care, dressing changes, and information on their intravenous pump. It is often useful

for the patient to meet their home care nurse (who will continue the education process at home until the patient or caregiver is self-sufficient) prior to discharge. The

treating physician should have some familiarity with

appropriate catheter care and the identification of complications associated with long-term TPN, including

catheter-related infections, occlusions, and metabolic complications.

Patients should not be discharged home until their

fluid and electrolyte requirements have stabilized. Once home, office visits and laboratory monitoring should initially be more frequent, although the stable patient who has minimal difficulty generally can visit the office and have routine laboratory testing done as infrequently as 3 times a year.

Patients in whom TPN is being weaned, and who acquire _75% of the nutritional needs parenterally, should have vitamin (usually fat-soluble vitamins) and trace metal (Zn, Cu, Se) analyses performed 2–3 times yearly, and whenever possible deficiencies are clinically recognized. Vitamin K is not a constituent of all parenteral multivitamin solutions, although vitamin K is

present in the intravenous lipid emulsion. Therefore, the prothrombin time should be regularly monitored, especially in those patients who lack residual colon. During clinic visits, the catheter exit site or skin overlying an implanted infusion port should be examined for warmth, erythema, and tenderness, and the catheter dressing should be examined for purulent exudate, which may signal infection. A properly maintained catheter may remain in place for many years.

Medication Absorption

Oral medication absorption is often impaired and

larger doses, intravenous, or sublingual delivery may be

required; significant interpatient variability may be observed.

Role of Surgery

Nontransplant Surgery

Restoration of intestinal continuity, such as reanastomosis of small intestine with colon, should be

performed whenever possible, because it can be performed with relatively low morbidity and mortality (often with discontinuation of TPN). Other forms of bowel

lengthening surgery have significant associated morbidity and mortality, and therefore should be considered only in select patients.

短肠综合征及其处理

临床外科杂志 2000年第2期第8卷 综述与讲座

作者：吴肇汉

单位：吴肇汉（200032 上海医科大学附属中山医院外科）

关键词：短肠综合征；诊断；治疗

［摘要］短肠综合征(SBS)是消化、吸收不良所致的营养不良综合病征。因病使残留小肠不足60 cm或＜1 cm/kg，易致本病。影响SBS代偿的因素有年龄、摄食情况、回盲瓣和结肠是否完整等。肠外营养和肠内营养已可能使SBS者得以长期生存。谷氨酰胺、生长激素及膳食纤维的联合应用可促使SBS者之代偿。

［分类号］R574.5 ［文献标识码］C

［文章编号］1005-83(2000)02-0113-02

短肠综合征(short bowel syndrome,SBS)是由于小肠消化、吸收面积不足而引起的营养不良综合病征。最常见的原因是小肠被广泛切除，例如肠扭转、肠系膜血管栓塞或血栓形成，以及Crohn病多次手术等。术后主要表现为消化、吸收功能不良，继而发生不同程度的营养不良，严重者可危及生命。

在临床实践中，当由于病变而需广泛切除小肠时，外科医师很需要有一个明确的SBS预测标准，即多少小肠被切除、或残留多长小肠必然会导致SBS，这一标准对手术方案的确定是具有很重要的指导意义的。在经典书籍中，曾把“切除小肠70%”作为诊断SBS的标准，但这种方法的实用价值不大，而且病人小肠总长度的个体差异也很大。另外，“残留小肠不足100 cm”的诊断标准也欠妥当，因为其中相当多的病人最后并不出现SBS症状。目前认为，SBS的预测标准应是残留小肠＜60 cm，或以体重计＜1 cm/kg。这一标准很实用，也容易记忆。这里需要强调一点，病人的结肠情况与其SBS表现及其代偿有密切关系。如果SBS病人保存着完整的结肠及回盲瓣，则症状较轻，而且较易代偿。反之，同时缺失部分结肠及回盲瓣者，症 状可很显著，代偿也更困难。根据这些标准，外科医师应在手术中尽量保留至少60 cm的小肠，也不要轻易切除回盲瓣及结肠，使病人术后仍能保持基本的消化、吸收能力。据此标准，在术中就可预测其术后的发展，制定术后治疗方案将会更确切。

SBS所致的一系列病理生理改变已不必再予赘述。关于SBS的代偿及其影响因素，尚有进一步强调之必要。大量临床资料表明，除残留小肠＜30 cm并同时丧失右半结肠之外，大多数SBS病人经过代偿几乎都能使肠道消化、吸收功能基本恢复。在影响代偿的许多因素中，以年龄的影响最大。年轻人或儿童，代偿能力很强。反之，老年人就很难代偿。保留回盲瓣是利于代偿的另一个主要因素。SBS病人应坚持摄食，尽管此时食物难以被完全消化吸收，但食物的刺激对于促进残留小肠代偿具有十分重要的作用。克服恐惧心理也很重要。失代偿期的SBS病人在摄食之后，往往便次增多，粪便稀。而且含有较多消化液，肛周皮肤可有不适感，甚至糜烂。此时不应因此而停止摄食，可采取口服一些止泻剂、肛周皮肤涂抹油膏等措施，症状大都能缓解。另外，克服SBS症状还需要足够的耐心，其代偿期相当长，约需1～2年。视残留小肠长度、结肠完整性及年龄等的情况，各病人的代偿期也长短不一。

在SBS病人的失代偿期，以肠内营养(EN)或肠外营养(PN)补偿口服摄食之不足可以达到十分理想的效果，在临床上已被普遍采用。EN制剂的品种很多，其中以含肽类、氨基酸及脂肪酸的产品适合SBS病人使用。常用的产品有百普素(pepit-2000)及爱伦多(Elental)等。其中的各种成分无需再消化即可被充分吸收，提供机体以全面的营养成分。遗憾的是这些产品的口味欠佳，虽已调配成适合口服，但毕竟与食物不同，病人往往不愿每天大量服用。而间断、少量服用这类EN制剂就难以达到维持营养的目的了。

近10余年来，肠外营养在治疗SBS病人方面已取得了显著成绩，从根本上改善了SBS病人的预后。PN可能补充SBS病人所需要的全部营养物质，包括葡萄糖、脂肪、氨基酸、电解质、维生素及微量元素。目前可供PN的市售产品种类很多。常用的氨基酸溶液有凡命(Vamin)、氨复命、14-氨基酸-823及乐凡命(Novamin)等。不同产品的浓度及含氮量也不同，可根据供氮(0.15～0.2) g/kg·d计算其用量。热量物质应兼含葡萄糖及脂肪乳剂。其中葡萄糖浓度常需达到20%～50%，脂肪乳剂可任选10%或20%浓度。脂肪乳剂有长链(LCT)及中长链(MC/LCT)二种。后者适用于肝功能不良者。糖脂比例以1～2∶1为宜，总供热量以体重计为(20～30) Kcal/kg*d。上述热、氮物质需在无菌环境下混合在3 L塑料袋内。溶液中再酌情加入电解质、维生素及微量元素，然后经中心静脉途径输入。如上所述，SBS病人的代偿期相当长，因此PN的输入应为中心静脉途径。为防止导管败血症的发生，导管的置管过程应严格无菌技术，在经锁骨下静脉或颈内静脉穿刺置管后，导管经皮下隧道(20 cm左右)从前胸壁引出。另外，为提高病人的生活质量、节省开支，可在对病人及其家属培训后，在家中由病人自行实施PN，称家庭肠外营养(home parenteral nutrition,HPN)。至今已有不少成功经验，值得推广。

但是，长期PN毕竟还会发生一些并发症，例如肝脂肪浸润、胆汁淤积、肝功能受损及导管性败血症等。因此，努力探索一些方法以加快残留小肠的消化吸收功能的代偿，使病人最终摆脱HPN，已成为近年来研究的热点。现已发现，谷氨酰胺(glutamine,Gln)、生长激素(growth hormone,GH)及膳食纤维(diet fibre)对残留小肠有明显促代偿作用。Gln是肠粘膜细胞的能源物质，对肠粘膜细胞的增殖及代谢具有显著的促进作用。食物中含Gln很丰富，但在常规HPN中并不含Gln，需要专门给予补充。关于GH，以往在成人学科甚少应用，但其促进增生的作用是完全能被临床医师所接受的。膳食纤维的作用主要是能在细菌作用下产生短链脂肪酸(SCFAs)，后者对结肠有营养及促代偿作用。已有报道，用Gln+GH+含纤维的高碳水化合物、低脂的饮食对150例SBS患者进行综合治疗，取得了相当好的效果。Gln用量为0.16 g/kg*d(静脉)或口服30 g/d。GH为(0.03～0.14) mg/kg*d，26 d为一疗程。全组病人有58%能完全摆脱HPN。但至今类似的报道的文章还不多，还有待进一步探索、证实。

在分析SBS病人代偿的资料中，有些情况引起人们很大兴趣。在上述150例SBS病例中，残存小肠＜30 cm者有21例，其中小肠仅留0～10 cm者有6例。这些病例经过上述综合治疗后居然有76%的病人可摆脱HPN，或是明显减少HPN用量。我院1例因肠扭转坏死作全小肠切除及右半结肠切除的病人，术后持续HPN已超过13年，生活质量很好。在她HPN后5年及10年时，曾用15N-氨基酸作肠吸收试验，测定结果显示，其15N-氨基酸吸收率竟然高达66%。由此可知，上述SBS病人残留肠道中的一部分——结肠，在代偿中扮演了重要的角色。当小肠严重残缺时，结肠也开始承担一定程度的吸收功能。尽管这种代偿还不足以满足机体的需要，但至少能使SBS症状有所缓解。由此，我们在处理SBS相关的手术时，千方百计保住结肠及回盲瓣的完整性是具有重要意义的。

对于SBS病人的治疗，除上述EN、PN支持，以及一系列促代偿措施之外，手术治疗方面尚未有突破性的进展。理论上，小肠移植应属SBS病人最理想、最彻底的治疗手段。但由于小肠及其系膜富含淋巴组织，移植后的排斥反应很难控制，至今其结果远不及肝、肾及心脏移植。因此，目前尚不能列为SBS病人的常规治疗手段。除此之外，小肠倒置术及结肠间置术被用于SBS病人已有多年，有一定疗效。小肠倒置是取末端小肠8 cm，切断后带蒂转180°后，再重新吻合。结肠间置术是取15～20 cm带系膜横结肠间置于小肠之间。这两种手术都是能使食物在小肠的停留时间延长，有利于食物的消化吸收。

随着医学科学的发展，SBS的治疗已有了相当进步，改善、维持各类SBS病人的营养状况已成为可能，HPN的发展更使病人的生活质量大为提高，一些促代偿的措施也正逐步完善。小肠移植中的难点也在深入研究，有望在不久的将来取得新进展。总之，SBS的治疗具有美好的前景。

短肠综合征 [编辑本段]

疾病概述

短肠综合征是由于不同原因造成小肠吸收面积减少而引起的一个临床症候群，多由广泛小肠切除所致，有时也可由小肠短路手术造成，由于上述疾病造成保留肠管过少，引起营养物质的吸收障碍，而表现为腹泻和营养障碍。严重者可危及病人生命。 [编辑本段]

疾病分类

普通外科 [编辑本段]

疾病描述

短肠综合征是因小肠被广泛切除后，小肠吸收面积不足导致的消化、吸收功能不良的临床综合病征。 [编辑本段]

症状体征

其主要临床表现为早期的腹泻和后期的严重营养障碍。早期的症状是不同程度的水样腹泻．多数病人并不十分严重，少数病人每天排出水量可达2.5—5.0L，可使脱水、血容量下降、电解质紊乱及酸碱平衡失调。数天后腹泻次数逐渐减少，生命体征稳定，胃肠动力开始恢复，但消化吸收功能极差。 若无特殊辅助营养支持治疗措施，病人则会逐渐出现营养不良症状，包括体重减轻、疲乏，肌萎缩、贫血和低清蛋白血症等。短肠综合征者促胰液素、促胆囊收缩素及肠抑胃素的分泌均减少，而幽门部胃泌素细胞有增生现象，以致约40％-50％病人有胃酸分泌亢进。这不仅可使腹泻加重，消化功能进一步恶化，并可能并发吻合口溃疡。十二指肠内PH值的降低使胰脂酶失活，从而脂肪泻增加。由于胆盐吸收障碍，影响肠肝循环，胆汁中胆盐浓度下降．加之上述肠激素分泌减少使胆囊收缩变弱．易发生胆囊结石(比正常人高3-4倍)。钙、镁缺乏可使神经、肌肉兴奋性增强和手足搐

搦。由于草酸盐在肠道吸收增加，尿中草酸盐过多而易形成泌尿系结石。长期缺钙还可引起骨质疏松。长期营养不良，可恶化导致多器官功能衰竭。

[编辑本段]

疾病病因

最常见的病因是肠扭转、肠系膜血管栓塞或血栓形成和Crohn病行肠切除术所致。 [编辑本段]

病理生理

食物的消化、吸收过程几乎均在小肠内进行，其中某些营养成分的吸收有其特定部位，例如铁、钙主要在空肠吸收．而胆盐、胆固醇、维生素B12等则是在回肠吸收。当该段小肠被切除，则相应成分的营养物质的吸收就会受到明显影响。回盲瓣在消化、吸收过程中具有很重要的作用，既可延缓食糜进入结肠的速度．使其在小肠内的消化、吸收更完全，又能阻止结肠内细菌的反流，保持小肠内的正常内环境。正常人的小肠长度长短不一，个体差异较大，但任何个体的肠吸收能力均远超过正常的生理需要。因此，当50％小肠被切除后可不出现短肠综合症。但若残留小肠﹤l00cm,则必定会产生不同程度的消化和吸收功能不良。小肠越短，症状就越重。切除回肠后引起的营养障碍比切除空肠更明显。如同时切除了回盲瓣，则功能障碍更严重。 短肠综合征者残留小肠的代偿改变表现为小肠粘膜高度增生，绒毛变长、肥大，肠腺陷凹加深，肠管增粗、延长，使吸收面积及吸收能力增加。食物的直接刺激可使小肠代偿性增生。代偿期约需1-2年，可望有半数病人完全得到代偿，恢复饮食并维持正常营养状态。 [编辑本段]

诊断检查

本病的诊断主要依靠病史和临床表现。 [编辑本段]

治疗方案

由于对短肠综合征代谢变化的充分认识，以及日趋成熟的营养支持治疗和促代偿措施，本病的治疗效果较以往已大为改善。 在术后最初几天，首先需治疗的是由于严重腹泻而导致的脱水、低血容量、电解质紊乱及酸碱失调。根据生命体征(血压、脉率、呼吸率)、动脉血气分析及血电解质(钾、钠、氯、钙、镁及磷)测定结果．确定静脉补充晶、胶体溶液量及电解质量。若有代谢性酸中毒，应补充5％碳酸氢钠溶液以纠正之。 待病人循环、呼吸等生命体征稳定后(约3-5天)，则应尽早开始全肠外营养(TPN)支持．以补充病人所必需的营养物质，包括能量物质(葡萄糖、脂肪乳剂)、蛋白质合成的原料(复方氨基酸溶液)、各种电解质及维生素等。目前的TPN已能满足机体的需要，并发症也不多，因此已被广泛应用。为减少排便次数，可酌情给予肠动力抑制药物，如口服阿片酊、可待因或洛哌丁胺等。口服消胆胺可消除胆盐对结肠的刺激，也能减轻腹泻。为控制高胃酸分泌，可口服抗酸药和静脉用H2受体阻滞剂如西咪替丁、雷尼替丁等。 病情渐趋稳定后，可以开始经口摄食。先以单纯的盐溶液或糖溶液，逐步增量。随肠代偿的过程．可逐步过渡到高碳水化合物、高蛋白、低脂肪、低渣饮食。经口摄食所不足的那一部分，仍需经肠外营养途径补充。可选用专用于短肠综合征者的肠内营养制剂。其主要成分是含肽或氨基酸、葡萄糖及游离脂肪酸等。各成分不必再消化即可被很快吸收。这类产品常有特殊味道，故常需经管饲给予。 有些特殊物质对小肠功能的代偿具有显著促进作用，如谷氨酰胺、短链脂肪酸、纤维素、生长激素及胰岛素样生长因子等，都已开始临床应用。上述几种物质的联合应用可望使短肠综合征者的代偿过程提早完成。但如果残留小肠仅为0-30cm，其中相当多的病人最终仍难以代偿，以致单靠经口摄食无法维持正常的营养状态，必须长期依赖肠外营养的支持。这种长期局外营养支持常可在病人家中实施，病人及其家属需先接受培训，掌握无菌术及营养液配制技术。国内已有实行家庭肠外营养长达14年的成功经验。 短肠综合征的手术治疗方面，小肠移植术虽被认为是短肠综合征最彻底的治疗方法，但由于移植术后严重的排斥反应至今尚难克服，因此目前还无法广泛用于临床。此外，小肠倒置术及结肠间置术均能延长食物通过肠道的时间，有一定的实用价值，可根据病人的具体情况选择使用。 [编辑本段]

疾病预防

尽量避免过多切除小肠，是预防本综合征发生的关键。 [编辑本段]

用药安全

肠功能初步恢复时，可选用低蛋白、低脂肪流质，如稀米汤、稀藕粉、果汁等，少量多餐。

短肠综合征

2008年03月13日 星期四 23:13

短肠综合征常见于小肠大部分切除后，由于小肠吸收面积不足，患者会出现以腹泻、水电解质紊乱、严重营养不良为主的临床表现，其症状的轻重与预后取决于小肠切除的长度、部位和是否保留回盲瓣。一般切除50%以下的小肠不会出现短肠综合征，但切除70%或更多的小肠则会出现严重营养障碍，如不予以合理的营养支持则会危及生命。由于每个人小肠的长度不尽相同，也主张以剩余小肠的实际长度来预测，多数认为剩余的小肠尚有100cm以上时，通过及时合理的营养治疗，小肠可发生代偿性变化如：肠粘膜增生、肠管扩张及延长、运动减缓，从而增加吸收面积及延长排空时间，同时胃的消化及大肠的吸收功能也会代偿性增加，若有完整的回盲瓣，患者就能吸收足够的营养物质而不发生短肠综合征。剩余小肠在100cm以下甚至60cm以下时，则会出现严重的营养吸收障碍。由于食糜在回肠中停留的时间比在空肠中停留的时间长，并且胆盐、胆固醇、维生素B12只在回肠吸收，因此切除回肠更易引起脂肪泻而导致严重营养障碍。切除回盲瓣会加速小肠中的食糜排入结肠，加重营养物质吸收不全。在患者出现短肠综合征时，应根据病情和残留小肠的长度及切除部位积极进行合理营养支持，挽救患者生命。

临床上最初以严重腹泻为主，每日可高达5~10L，导致进行性脱水、血容量降低、血压下降、水电解质平衡失调。此时也可发生感染。数日至数周后腹泻趋于减少，残留小肠吸收功能有所恢复，但存在严重营养不良，表现为体重持续下降、肌萎缩、贫血、血浆蛋白低下，吻合口不易愈合等。钙、镁丢失可引起神经肌肉兴奋性增强及肢体抽搐。胃酸分泌亢进，易并发溃疡病。高草酸尿症易形成泌尿系结石。胆盐吸收障碍易导致胆结石。维生素D和钙的吸收障碍可引起骨质疏松和骨质软化症。维生素B12吸收障碍可引起巨幼红细胞性贫血。 营养相关因素

小肠是人体主要的消化吸收器官，长达5m以上，分为十二指肠、空肠和回肠。它的吸收功能主要在十二指肠、空肠近端及回肠远端完成，完整的回盲瓣可提高残留小肠的吸收能力。小肠不同部位对营养物质的吸收具有选择性，除维生素B12、胆盐、胆固醇仅在回肠吸收外，其它营养物质几乎均能在小肠各段被吸收。小肠广泛切除后会引起营养物质在体内代谢改变：

1、净吸收面积的减少 小肠变短后小肠的吸收面积减少，食糜在肠腔内停留时间变短，各种营养物质吸收不完全，能量摄取不足、负氮平衡、体重减轻、免疫功能下降。

2、切除小肠上段对吸收功能的影响 由于碳水化合物、蛋白质、脂肪及钙、铁等矿物质主要在十二指肠、空肠近端吸收，若主要切除上段小肠，三大生热营养素部分矿物质的吸收会受到影响，出现血浆蛋白低下，缺铁性贫血，血钙下降使甲状旁腺功能亢进而引起骨质疏松、骨质软化症等。如果有足够长的回肠和完整的回盲瓣，以上影响会减轻。

3、切除小肠下段对吸收功能的影响 由于胆盐、维生素B12只在回肠末段吸收，若下段小肠切除，可造成胆盐吸收障碍。胆盐的肝肠循环被阻断，肝脏不能合成足够的胆盐，从而影响脂肪的吸收，使大量脂肪滞留在肠腔内而引起脂肪泻。脂

肪吸收障碍同时伴有脂溶性维生素的大量丢失，维生素D缺乏加重了骨质疏松和骨质软化症。肠腔内的脂肪酸还与草酸竞争与钙离子结合成钙皂，不但使钙的吸收率下降，而且使草酸与钠离子结合成可溶性草酸盐被大肠重新吸收入血，形成高草酸尿症，易引起泌尿系结石。胆汁中胆盐的缺乏会造成胆结石。维生素B12的缺乏会导致巨幼红细胞性贫血。腹泻使体液大量丢失，引起水电解质紊乱，酸碱平衡失调，营养素吸收不全，甚至造成严重的蛋白质—能量营养不良，重者危及生命。

4、切除回盲部对吸收功能的影响 回盲瓣可延缓食糜进入结肠，使食物中的营养成分充分吸收，若切除回盲瓣则会加重营养不良。

5、对胃酸分泌的影响 小肠的大段切除会加速胃的活动并产生大量胃酸，过量的胃酸易造成溃疡，进而影响营养物质的消化吸收。 营养治疗原则 1、肠外营养支持

术后应立即采用静脉方式补充营养，并使肠管得到必要的休息。根据手术具体方案和临床表现积极进行肠外营养支持，这不但能减少腹泻而且能纠正因严重腹泻造成的水电解质紊乱和营养不良。肠外营养可提供机体基本的能量需求，维持正氮平衡，并根据临床监测的生化指标和营养指标补充维生素及矿物质。一般可按如下供给：能量125.52~167.36KJ（30~40kcal）/(kg·d)，蛋白质占总能量15%（氮热比为1׃166.66），碳水化合物和脂肪占总能量85%左右，二者之比为1׃ 1，其它营养素根据生化检查结果适量补充。 2、肠内营养支持

患者肠道功能初步恢复后，应尽早经口或管饲进行肠内营养支持。食物对肠道的刺激可促进肠粘膜增生、肥大，增加刷状缘酶的活性，有利于剩余小肠建立功能代偿。肠内营养要循序渐进，使患者能逐渐增加通过肠道吸收营养物质的量，同时逐渐减少肠外营养供给量，最终达到完全肠内营养。开始时一般以单纯葡萄糖液、单纯盐溶液试食，以确定患者肠道是否通畅及其适应能力。随后可用无蛋白、无脂肪流食作为过渡，少量多餐，增加对肠道的刺激。待肠道适应后，可用要素膳。要素膳要遵循剂量由少到多、浓度由稀到稠、速度由慢到快的原则，逐渐增加能量和蛋白质的量，并尽量采用以中链三酰甘油为主的低脂无渣要素膳。营养素可按如下供给：能量125.52~167.36KJ(30~40kcal)/ (kg·d)，蛋白质占总能量的15%，碳水化合物占75%，脂肪占10%。随着病情的好转，肠道吸收功能逐步恢复，最终进食高蛋白、高碳水化合物、低脂肪的少渣软食。此膳食每日提供的营养素如下：能量146.44~167.36KJ(35~40kcal)/(kg·d)，蛋白质占总能量15%，碳水化合物占75%左右，脂肪低于30g/d。少食多餐。若患者仍需管饲可将食物制成匀浆膳。在选用食物时应避免高草酸食物，如菠菜、茄子、青椒、豆腐、草莓、葡萄等。及时、合理的肠内营养可促进肠道功能恢复，改善患者生存质量。 对肠内营养无法提供或提供不足的能量和营养素，如维生素B12、必需脂肪酸、脂溶性维生素、铁、钙、镁、锌等应经静脉及时补充。 3、谷氨酰胺的应用

适当增加谷氨酰胺的供给，可改善肠粘膜营养状态，促进小肠粘膜增生。经口采用L-谷氨酰胺悬浮液，经静脉多采用谷氨酰胺双肽。 食物的选择 宜用食物：

1、肠道功能初步恢复时，宜选用低蛋白、低脂肪流食，如稀米汤、稀藕粉、果

汁水、维生素糖水、胡萝卜水等，每次50~100ml，每日3~6次。

2、肠道功能进一步恢复，可选用营养均衡型肠道营养制剂，如安素、立适康等。 忌（少）用食物：高脂、高纤维、辛辣刺激性食物，如动物脂肪、芹菜、菠菜、韭菜、葱、蒜、辣椒等。 食谱举例

以肠道功能已恢复的成年男性患者为例（见下表）。 短肠综合征软食食谱

早餐 糖花卷（面粉100g），鸡蛋50g 加餐 牛乳150ml，面包50g

午餐 米饭100g，虾仁（虾仁50g）炖小白菜（150g） 加餐 冲藕粉100ml（藕粉15g，糖10g，鸡蛋25g） 晚餐 馒头100g，冬瓜氽丸子（鸡肉50g，冬瓜100g） 加餐 牛乳100ml，松糕50g

能量 8.18MJ(1955kcal) 蛋白质 76.8g(16%)脂肪 25.4g(12%) 碳水化合物 3.6g(72%)