Parenteral nutrition (PN) is used when dogs and cats are unable to consume or tolerate adequate enteral nutrients. A total parenteral nutrition (TPN) solution typically covers 100% of a patient’s nutritional and caloric needs, while partial parenteral nutrition (PPN) covers a fraction of that. PN must be delivered into a central or peripheral vein, depending on osmolarity of the mixture. This study investigated whether PN can effectively deliver the energy requirements of critically ill animals without increased risk for death. Cases from 319 dogs and 112 cats were retrospectively reviewed, with the most common diagnosis being pancreatitis (n =109 dogs, n = 34 cats). The only metabolic risk factor associated with death was hypercreatininemia in dogs (8/79), which was independent of the association between chronic kidney disease (CKD) and death. Negative associations for survival included longer duration of inadequate caloric intake before PN, hepatic lipidosis in cats, and CKD in dogs. Despite the frequency of some complications, hyperglycemia was the only metabolic complication that could have interfered with PN administration. Prevention of mechanical complications and concurrent administration of enteral feeding are essential for improving patient outcome. Overall, PN adequately met the resting energy requirement for many critically ill animals.

Commentary: Although PN can be a lifesaver when enteral feeding is not an option for critically ill patients, it invariably includes some “real world” concerns. First, to administer TPN, a large-gauge catheter must be aseptically placed in either the caudal vena cava or jugular vein. When PPN with a small-gauge catheter is elected, daily patient monitoring for phlebitis also is necessary. In addition, catheter placement requires special training, and the patient may need to be sedated or lightly anesthetized. Second, PN must be ordered individually for every patient (ideally by a veterinary nutritionist) and requires daily monitoring of serum electrolytes, glucose, and phosphorus. Individual bags only last up to 24 hours and thus can be cost-prohibitive for some clients. On the other hand, PN raises the bar for clinical excellence when incorporated into a practice. Practitioners who choose PN need to emphasize its importance in a patient that is hospitalized for more than 48 to 72 hours.—Heather Troyer, DVM, Diplomate ABVP, CVA

Factors associated with adverse outcomes during parenteral nutrition administration in dogs and cats. Queau Y, Larsen JA, Kass PH, et al. J VET INTERN MED 25:446-452, 2011.