Feeding
Feeding tests enteral nutrition timing, energy and protein targets, refeeding syndrome and parenteral nutrition indications.
Core rules
- Start enteral nutrition within 24–48 h in haemodynamically stable ICU patients. Trophic feeding is acceptable during shock with escalating vasopressors.
- ESPEN targets: 25–30 kcal/kg/day and protein 1.2–2.0 g/kg/day; use adjusted weight in obesity.
- Refeeding syndrome: hypophosphataemia, hypokalaemia and hypomagnesaemia. Risk is higher with low BMI, weight loss and little recent intake. Give thiamine before feeding.
- Parenteral nutrition is indicated when enteral nutrition is contraindicated and nutrition is likely inadequate for more than 3–7 days.
- Do not routinely measure gastric residual volumes; elevate the head of the bed 30–45°.
Worked example
A 70-kg man with BMI 22 needs 25 kcal/kg = 1,750 kcal/day and 1.5 g/kg = 105 g protein/day. If he is on norepinephrine 0.3 µg/kg/min, start trophic enteral feed and reassess; do not push full calories during unresolved shock.
Traps
- Overfeeding raises CO2 and worsens hyperglycaemia.
- Missing refeeding syndrome because phosphate was not checked.
- Delaying enteral nutrition for absent bowel sounds.
- Using actual body weight in severe obesity without adjustment.