[Perioperative parenteral nutrition. For whom? How?]

Preoperative artificial feeding (for 7 to 15 days) through an enteral or parenteral route is justified only in a subgroup of patients suffering form severe denutrition, who are scheduled for surgery with high morbidity or mortality. Postoperatively, the field of indication is broader, and it includes any patients who cannot soon feed themselves enough to catch their resting energy expenditure plus 20%. The administration route should use the technique with the lowest morbidity (enteral feeding) and the lowest costs. The role of new substrates (structured lipids, glutamine, trace elements) on immunity should be specified.