A guide to enteral nutrition in intensive care units: 10 expert tips for the daily practice

Abstract

The preferential use of the oral/enteral route in critically ill patients over gut rest is uniformly recommended and applied. This article provides practical guidance on enteral nutrition in compliance with recent American and European guidelines. Low-dose enteral nutrition can be safely started within 48 h after admission, even during treatment with small or moderate doses of vasopressor agents. A percutaneous access should be used when enteral nutrition is anticipated for ≥ 4 weeks. Energy delivery should not be calculated to match energy expenditure before day 4-7, and the use of energy-dense formulas can be restricted to cases of inability to tolerate full-volume isocaloric enteral nutrition or to patients who require fluid restriction. Low-dose protein (max 0.8 g/kg/day) can be provided during the early phase of critical illness, while a protein target of > 1.2 g/kg/day could be considered during the rehabilitation phase. The occurrence of refeeding syndrome should be assessed by daily measurement of plasma phosphate, and a phosphate drop of 30% should be managed by reduction of enteral feeding rate and high-dose thiamine. Vomiting and increased gastric residual volume may indicate gastric intolerance, while sudden abdominal pain, distension, gastrointestinal paralysis, or rising abdominal pressure may indicate lower gastrointestinal intolerance.

Keywords: Critically ill; Energy metabolism; Gastrointestinal dysfunction; Muscle wasting; Refeeding syndrome; Sarcopenia; Stress response.

Fig. 1

Acute phase catabolic response to critical illness and need for protein and non-protein calories. Adapted from: Ref. [57]

Fig. 2

Recommendations for the progression of enteral nutrition delivery, micronutrients delivery and management of refeeding. Adapted from: CHUV Lausanne and Gelderse Vallei Hospitals. The X axis represents the time from admission (days, arbitrary example) and the Y axis the percentage of nutritional goal determined by a computer protocol using sex, height, weight (first 3 days) and later by indirect calorimetry or calculation prioritizing the avoidance of energy overfeeding. Regular (hourly) checks of intakes including the amount of non-nutritional energy (propofol, glucose, citrate) are recommended to adapt the infusion rate. Multi-micronutrients are administered IV until the dietary recommended intakes are met by the EN solution. The screening for refeeding syndrome is based on daily phosphate determination from day 2. In case of hypophosphatemia (hypoP) (serum phosphate (PO4) < 0.65 mmol/l, or a drop from baseline > 0.16 mmol/l occurring within 72 h of the start of EN) decrease the amount of energy delivered to a maximum of 500 kcal/day, supplement phosphate, magnesium (Mg) and potassium (K) and additional boluses of thiamine (vit B1, 500–1000 mg IV)

Fig. 3

Screening for enteral feeding intolerance (ARB). Differentiation between EFI in different parts of GI tract and respective terminology has not been uniformly established. *Suggested contraindications to EN are uncontrolled shock, uncontrolled hypoxemia and acidosis, uncontrolled upper GI bleeding, gastric aspirate > 500 ml/6 h, bowel ischemia, bowel obstruction, abdominal compartment syndrome, and high-output fistula without distal feeding access. # GRV between 200 and 500 ml can be considered increased and > 500 ml a cut-off for discontinuation of EN