重症患者营养治疗(压疮护理学习班)课件.ppt

* 谷氨酰胺是体内浓度最高的游离氨基酸，因此，它起着在体内的各种组织和器官之间转运氮源的作用。所以，人们又称谷氨酰胺为机体中的“氮梭”。 谷氨酰胺的生理作用有两大方面： 一方面，谷氨酰胺可以促进蛋白质的合成，是蛋白质合成的前体；也是嘌呤、嘧啶、核苷酸和氨基糖合成的前体； 另一方面，谷氨酰胺是快速增殖细胞的主要代谢原料，比如肠粘膜细胞、免疫细胞等快速增殖细胞主要能量就来自于谷氨酰胺。 * 我们说谷氨酰胺是一种条件必需氨基酸，因为，在某些特定的条件下，比如分解代谢时，谷氨酰胺会严重缺乏。 引起谷氨酰胺缺乏的原因很多，比如：创伤、局部或全身性损伤、大手术、感染、肠代疾病、烧伤、营养不良、胰腺炎等都会引起细胞内谷氨酰胺水平显著下降。并且，这种下降不能被传统的营养支持所扭转。 * 如果此时得不到谷氨酰胺补充的话，谷氨酰胺水平持续下降的后果将导致： 1、病人肌肉蛋白降解—病人将处于持续分解代谢状态，不利于病人的恢复； 2、肠道黏膜的通透性增加—导致肠道细菌和毒素移位入血； 3、病人免疫功能受损—病人免疫机能下降。 而只有补充谷氨酰胺才能纠正这种不良状况！ * 胃肠功能障碍发生的时间长短和严重程度不同，所带来营养不良的风险也不同。 * 营养不良肿瘤40%~80%，结肠癌50%，食管、胃、胰腺癌85% To avoid underfeeding and overfeeding and to optimize the benefits of nutrition support in ICU patients, precise measurement or calculation of caloric need is crucial. Accurate determination of REE is necessary in patients receiving nutritional support to ensure that their energy needs are met and to avoid the complications associated with over or underfeeding. Overfeeding caused by excess carbohydrate (CHO) or fat administration can result in fatty infiltration of the liver and subsequent pulmonary compromise and mild to moderate hepatic dysfunction. Underfeeding can lead to poor wound healing, decreased immune function, and reductions in respiratory muscle strength, vital capacity, with redistribution of body mass from muscle to visceral tissue. * In the patient in the ITU meeting energy requirements does not prevent loss of lean body mass, and exceeding requirements causes metabolic complications and may precipitate organ dysfunction leading to increased ventilator dependence and length of ITU stay. Energy balance is the difference between energy in and energy used. A negative energy balance occurs when demands are not met with appropriate nutritional support. Maintenance of a positive metabolic balance is imperative for optimal patient outcomes. Accumulation of a negative energy balance is detrimental and leads to complications and a longer hospital stay. To achieve a balance between appropriate nutritional