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Br Med J 2001。（C）7. 危重病患者急性應(yīng)激期營養(yǎng)支持熱量目標(biāo)為20~25 kcal/；在應(yīng)激與代謝狀態(tài)穩(wěn)定后，能量供給量需要可適當(dāng)增加至25~30 kcal/。（B）。（C）4. 只要胃腸道解剖與功能允許，應(yīng)首選EN。（A）3. 早期營養(yǎng)支持有助于改善危重病患者的臨床結(jié)局(A)。三、推薦意見1. 危重病患者，營養(yǎng)支持只有在生命體征穩(wěn)定（血流動力學(xué)、呼吸功能穩(wěn)定－包括藥物、呼吸機(jī)等治療措施控制下）的情況下才能進(jìn)行。對于病程較長、合并感染和創(chuàng)傷的危重病患者，在應(yīng)激與代謝狀態(tài)穩(wěn)定后能量補(bǔ)充需要適當(dāng)?shù)脑黾?，目?biāo)喂養(yǎng)可達(dá)30~35 kcal/，否則將難以糾正患者的低蛋白血癥[44,45]。此外，存在嚴(yán)重胃潴留或胃食管反流的患者，輔助胃動力藥物（胃復(fù)安等）有利于改善胃腸道動力[23,25,4143]。同樣，文獻(xiàn)證據(jù)表明，對于腸道功能存在的危重患者，經(jīng)胃管飼與經(jīng)空腸管飼對改善臨床結(jié)局無明顯的差別[3436]，但是對于胃、十二指腸功能障礙患者或具有高風(fēng)險(xiǎn)的危重病患者可以行空腸喂養(yǎng)，研究顯示經(jīng)胃十二指腸EN可刺激胰腺并引發(fā)大量胰酶分泌，而經(jīng)空腸EN則無此作用[37]，在這些患者中空腸喂養(yǎng)應(yīng)該在嚴(yán)格的臨床觀察下進(jìn)行[38,39]。但近來關(guān)于腸外營養(yǎng)的meta分析指出，對于那些嚴(yán)重營養(yǎng)不良、高代謝狀態(tài)、連續(xù)幾周時(shí)間不能進(jìn)行腸內(nèi)營養(yǎng)的患者，實(shí)施靜脈營養(yǎng)的有效性尚不確定[30]。EN不充分并存在營養(yǎng)不良風(fēng)險(xiǎn)患者需要PN支持[29]。研究顯示，危重病患者不能行EN提供營養(yǎng)且合并營養(yǎng)不良，如不給予有效的PN治療，死亡危險(xiǎn)將增加3倍[2628]。危重病患者胃腸結(jié)構(gòu)與功能可耐受EN時(shí)應(yīng)該選擇EN[21,22]。危重病患者應(yīng)首先考慮EN，因?yàn)樗稍讷@得PN相似的臨床營養(yǎng)效果，而且在全身性感染等并發(fā)癥發(fā)生及費(fèi)用方面優(yōu)于PN[19]。而一旦早期EN不能改善營養(yǎng)不良，即可于3d~5d起添加PN[14]。營養(yǎng)支持不足及蛋白質(zhì)能量負(fù)平衡，將直接導(dǎo)致營養(yǎng)不良發(fā)生，并與血源性感染相關(guān)，影響ICU患者預(yù)后[12]。對重癥顱腦損傷患者早期營養(yǎng)支持可能提高生存率，減少致殘率[10]。嚴(yán)重應(yīng)激后機(jī)體代謝率明顯增高，~ kg/d，發(fā)生營養(yǎng)不良（體重丟失≥10％）[3]。2002年，Kondrup等的Meta分析表明，常見重癥如大手術(shù)后、重癥急性胰腺炎、重度創(chuàng)傷、APACHE II10的住院患者即存在重度營養(yǎng)不良的風(fēng)險(xiǎn)[1]。二、證據(jù)臨床營養(yǎng)支持；營養(yǎng)支持開始時(shí)機(jī)對危重病患者來說，維持機(jī)體水、電解質(zhì)平衡屬于救命治療。只有在恢復(fù)階段，才能夠逆轉(zhuǎn)負(fù)蛋白質(zhì)平衡。但不同于饑餓所至的自身消耗，營養(yǎng)支持只能通過減少負(fù)能量—氮平衡，起到一定的代償作用，卻無法扭轉(zhuǎn)機(jī)體的分解代謝狀態(tài)。 122(7):1763–70.53. 江華，蔣朱明，羅斌，等. 免疫腸內(nèi)營養(yǎng)用于臨床營養(yǎng)支持的證據(jù):中英文文獻(xiàn)的系統(tǒng)評價(jià). 中國醫(yī)學(xué)科學(xué)院學(xué)報(bào)，2002，24：552558第四節(jié) 危重病一、背景許多危重疾病患者存在明顯的應(yīng)激過程，在創(chuàng)傷后最初階段以代謝減少為特征的“退潮期”后，分解代謝激素（胰高血糖素、兒茶酚胺和腎上腺皮質(zhì)激素）分泌增加，出現(xiàn)胰島素抵抗以及細(xì)胞因子、氧自由基、以及其他局部介質(zhì)增加等。132(5): 805–14.51. 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