ICU nutrition in the shocked, starved surgical patient — dose, route, protein, refeeding and glucose

Examiner probes

1. Day-two post-laparotomy, fluid-resuscitated but still on low-dose noradrenaline with a distended abdomen. Start full enteral feeds, trophic feeds, or parenteral nutrition — and defend the dose with the trials?^[1][3][6]
2. Vasopressors escalate overnight with rising lactate and no stool. Force the enteral rate up or switch strategy — what does the shock-gut evidence say?^[11]
3. He develops oliguric kidney injury. What protein dose — and what happens if you prescribe 2.2 g per kg per day?^[13][14]
4. Glutamine and antioxidant supplements are suggested for his multiorgan failure, and immunonutrition was mentioned for his upcoming GI-cancer resection. Separate the two answers.^[16][18]
5. He was starved 8 days pre-operatively and his phosphate falls after feeds start. Restrict or push through — with what numbers?^[21][9]
6. Glucose runs 12 to 15 on steroids and sepsis. Target 81 to 108 or 180 or less — and what convinced the world to switch?^[25]

Model responses

1. Trophic enteral early, no early PN — the deficit is tolerated physiology. EDEN: 1000 patients, 400 versus 1300 kcal for 6 days — vent-free days and death tied, intolerance worse on full.^[1] PermiT: 894 patients, 46 versus 71 percent of requirements with equal protein — 90-day death tied with no tolerance or infection difference.^[3] EPaNIC: 2312 versus 2328 — PN within 48 hours versus day 8, and day 8 won on speed, infections, cholestasis, ventilation and renal days.^[6] Start EN low-volume now, advance on tolerance and perfusion, and hold PN unless EN fails toward day 8.

2. Stop forcing — shock gut ischaemiates. NUTRIREA-2 randomised 2410 ventilated shock patients to isocaloric EN versus PN: death and infections equal, but enteral raised vomiting, diarrhoea, bowel ischaemia 19 versus 5 cases, and pseudo-obstruction.^[11] Bridge with PN while vasopressors escalate, examine and image the distended abdomen rather than prokineting through ischaemia, and re-attempt EN as shock resolves.

3. Usual-dose protein — high dose harms AKI. EFFORT: 2.2-plus versus 1.2-or-less g per kg per day — discharge alive 46.1 versus 50.2 percent, death 34.6 versus 32.1, harm in AKI and high failure scores.^[13] AKI post-hoc: HR 0.5 for discharge alive, RR 1.4 for 60-day death across all stages, harm gone only on replacement therapy.^[14] Prescribe usual dose, go lower with high SOFA, and never chase protein targets in multiorgan failure.

4. ICU cocktails harm; GI-cancer formulas help — never cross them. REDOXS: 1223 multiorgan-failure patients — glutamine trended death up with higher hospital and 6-month death, antioxidants nil.^[16] But perioperative arginine, nucleotide and omega-3 formulas in GI cancer surgery cut leak (OR 0.62), infections and stay by about 2 days across 90 trials — omega-3 alone nil, cystectomy nil.^[18] Refuse the ICU cocktail, offer the perioperative formula for the cancer resection.

5. Restrict — the phosphate fall is the signal the trial treated. The refeeding RCT: 339 adults, restriction versus standard — days alive after discharge tied but day-60 survival 91 versus 78 percent with longer survival and no safety concerns.^[21] Relative phosphate fall marks early-PN harm and poor admission prediction means serial measurement, not history, finds these patients.^[9] Restrict macronutrients temporarily, replete, go slow — especially with protein.

6. Cap at 180 or less — NICE-SUGAR ended tight control. 6104 patients: intensive 81-to-108 raised 90-day death 27.5 versus 24.9 percent through thirteen-fold severe hypoglycaemia, operative patients trending worse.^[25] The 5202-patient switch cohort then halved adjusted death odds on abandoning intensive control. Cap, measure often, treat lows as emergencies.