Total parenteral nutrition in clinically normal cats

Seven clinically normal cats were maintained on total parenteral nutrition (TPN) with nothing given PO for 2 weeks. The TPN solution consisted of a mixture of dextrose, amino acids, soybean oil emulsion, electrolytes, and vitamins. Three cats were fed calories in excess of published maintenance requirements, and they gained some weight, vomited occasionally, had oral ulcerations, and had signs of depression after 10 to 13 days on TPN. Four cats that were not overfed did well clinically and maintained stable body weights. All cats developed anemia and thrombocytopenia to varying degrees during TPN administration and had polyuria and serum triglyceride concentrations higher than normal fasting values. Some cats had changes in liver-specific biochemical variables. Hepatocellular swelling and vacuolation and small intestinal villous atrophy and fusion were the most common histopathologic changes seen after TPN. These changes were reversible when TPN was discontinued and the cats were returned to enteral nutrition.