Table 1 Areas of uncertainty – opposing views

Optimal caloric intake

Early match of EE.

Less than EE during the early phase.

Supplemental PN

When EN provision is less than 60% in early course of ICU stay not contraindicated.

Not before day 8 in patients with a body mass index of at least 17.

Optimal protein intake

Equal to nitrogen losses, up to 1.5 g/kg per day.

Less than nitrogen losses.

Re-feeding syndrome

Slowly increase nutritional support to prevent re-feeding syndrome consequences even if this results in increased energy deficit.

Early nutritional support improves outcome also in malnourished patients; re-feeding syndrome consequences should be monitored and immediately treated if necessary.

Role of indirect calorimetry

Yes (patients staying more than 4 days).

No.

Autophagy

Provision of nutrients should be reduced so as not to reduce autophagy capacity as early nutrients provoke a phenotype of suppressed autophagy in human and animal experiments, with functional consequences that impair recovery.

Although experimentally autophagy may be reduced in early critical illness, pharmacological autophagy activation remains to be tested clinically.

Antioxidants

Supplement in case of low levels of antioxidants.

Use pharmacological dosages.

Glutamine

In all patients on PN.

High-dose glutamine increases mortality in critically ill patients, regardless of route of administration.

Omega-3 lipid formulations

Use continuous enteral administration and avoid bolus administration.

Not beneficial in acute respiratory distress syndrome.

High-dose selenium 800 to 4,000 μg/day

High-dose trials (1,000 μg) show greater improvement than low-dose trials.

Potential for toxicity.

In selenium-replete populations, 800 to 1,000 μg may be ineffective.

Probiotics

Safe. Avoid use in pancreatitis patients with multiple organ dysfunction syndrome.

May be harmful in ICU patients when given post-pyloric with fiber.

Monitoring GRV

Accept GRV of 250 up to 500 mL per 6 hours.

Abandon GRV monitoring in medical patients and consider in surgical patients.