【排头兵学海】重症评估工具专题

肠内营养评估

　　当前，重症病人营养支持治疗相关指南及共识推荐危重症患者入住ICU24h-48h内尽早启动肠内营养。肠内营养有助于营养胃肠黏膜，增强神经内分泌功能，有益于保留肠道黏膜屏障功能和免疫功能。早期肠内营养与降低感染率，加速伤口愈合，缩短机械通气时间、ICU住院时间和总体住院时间，以及降低病死率有关。在临床实践中，由于ICU病人的个体差异性较大，不同病种或病程病人胃肠功能受损程度不同、对肠内营养的耐受性差异很大，胃肠功能障碍重症病人开展肠内营养支持治疗仍充满挑战。本期，对于胃肠耐受性和胃残余量的评估进行介绍。　　

1.Gastric emptying and gastric retention monitoring【胃排空与胃潴留监测】

Gastric residual measurement is the most common method for evaluating gastric retention, including classical measurement, modified measurement and ultrasound assessment. Gastric residual volume≥250 mL indicates feeding intolerance, and intervention therapy should be started as soon as possible.

胃残余量测量是评估胃潴留最常见的方法，包括经典测量法、改良测量法和超声检查评估法。胃残余量≥250 mL提示喂养不耐受，需尽早启动干预治疗。

胃残余量的测量方法

Classical measurement: After stopping nasogastric feeding, the nutrition pump tube was removed, and the nasogastric tube was connected with a 50 mL or 60 mL syringe. The total amount of stomach contents extracted from multiple syringes was the gastric residual amount.

经典测量：停止鼻饲后，脱开营养泵管，使用50 mL或60 mL规格注射器连接鼻胃管后回抽，多个注射器回抽得的胃内容物总量即为胃残余量。

FIGURE1-1 Gastric fluid is aspirated to determine gastric residual volume

（抽吸胃液确定胃残余量）

Ultrasound measurement: Bedside ultrasound evaluation of gastric residual volume in healthy or critically ill patients has a good linear relationship with its stomach contents. Measurements of the cross-sectional area (CSA) of the gastric antrum by ultrasound are performed as follows: The patient is supine, the head of the bed is raised 30°(if the vertebra or pelvis is fractured, the overall slope of the bed is raised 30°), and the convex array ultrasound probe is placed in the superior abdominal area of the patient. The probe is parallel to the longitudinal axis of the body, and the indicator point is pointed at the patient's head side. The probe is scanned from left to right, and the fundus of the stomach, the body of the stomach and the section of the pylorus can be observed in turn, and the sagittal cross-section image of the pylorus can be obtained. Anterior and posterior diameter (Dap) and cephalic and tail diameter (Dcc) were measured according to the formula: usCSA (cm2) = (Dap×Dcc×π) /4, stomach volume (mL) =27.0+14.6×CSA -- 1.28×age. Results of a systematic review showed that gastric volume >1.5 mL/kg indicated a high risk of aspiration.

超声检查测量：床旁超声检查评估胃残余量在健康人或重症病人的测量结果与其胃内容物量有良好的线性关系。通过超声检查测量胃窦横截面积（cross-sectional area，CSA）评估胃残余量的具体操作如下：病人仰卧位，床头抬高30°（若椎体或骨盆骨折，则床整体斜坡抬高30°），将凸阵超声探头放置在病人腹上区，探头与身体纵轴平行，指示点指向病人头侧，探头自左向右滑动扫描，依次可观察胃底、胃体及幽门切面，获取幽门部矢状位横截面图像，测量前后径（Dap）及头尾径（Dcc），根据公式：usCSA（cm2）=（Dap×Dcc×π）/4，胃容量（mL）=27.0+14.6×CSA‒1.28×年龄。一项系统性回顾分析结果显示：若测得胃内容量>1.5 mL/kg，提示高误吸风险。

FIGURE 1-2 The gastric contents were quantitatively determined by ultrasound

（经超声胃内容物定量测定）

2.Evaluation of tolerance to enteral feeding【肠内喂养耐受性评估】

Feeding intolerance refers to the reduction of enteral nutrient infusion during feeding due to various reasons. Assessment of feeding intolerance is usually based on gastrointestinal symptoms such as high residual stomach volume, vomiting, bloating, diarrhea, etc.

喂养不耐受指喂养过程中由于各种原因导致的肠内营养输注量减少。评估喂养不耐受通常基于胃肠道症状，如高胃残余量、呕吐、腹胀、腹泻等。