Transperitoneal absorption of glucose and amino acids for nutritional support

To evaluate the peritoneal membrane as an absorptive surface for nutritional support, 14 New Zealand rabbits with peritoneal catheters were rapidly infused with 75 mL/kg of a 5% glucose and 2.5% mixed amino acid solution. Plasma and peritoneal fluid glucose, amino acid, and electrolyte concentrations and osmolarities were measured serially for six hours following infusion, and nutrient absorptions were calculated. Plasma osmolarity rose minimally, peritoneal fluid osmolarity declined rapidly, and there was a small increase in peritoneal fluid volume. Peritoneal fluid concentrations of glucose and amino acids fell precipitously during the initial two hours, while plasma concentrations rose in reciprocal fashion. Two thirds of the glucose and 83% of the amino acid loads were absorbed at six hours, with most of the absorption occurring within the first two hours. Amino acid absorption was independent of molecular weight and configuration. While glucose and amino acids were rapidly absorbed in adequate amounts, an intraperitoneal nutrition support system will require fat to provide total energy needs.