Nitrogen utilization in uremic patients fed by continuous nasogastric infusion.

Patients with severe renal failure were continuously fed an electrolyte-free solution containing oligosaccharides plus 35 g of a mixture of six amino acids and four (or, in one study, five) nitrogen-free analogues via a small-bore nasogastric tube attached to a pump. They also ingested three small meals daily. Total caloric intake averaged 34 kcal/kg (of which 76% was infused). Total nitrogen intake averaged only 3.3 g (of which 68% was infused). Nevertheless, nitrogen balance was positive (average + 1.22 g/day). All components of nitrogen excretion fell to unusually low average values: urea nitrogen appearance, 1.14 g/day; non-urea urinary nitrogen. 0.63 g/day; fecal nitrogen, 0.48 g/day. Nitrogen requirement for balance on this regimen, estimated from linear regression, was only 2.0 g/day. Body weight did not change significantly. Serum albumin and transferrin remained normal. Thus, this regimen induces positive nitrogen balance despite low nitrogen intake.