Route

Animals should be offered the option to eat before each feeding. If oral intake is not possible or if an animal will not voluntarily consume enough calories of a complete and balanced diet to meet its energy and nutrient requirements, assisted nutritional support is indicated.

Planning for the feeding route before other procedures are performed is strongly recommended. If an animal with confirmed or anticipated anorexia is to be sedated or anesthetized for a diagnostic or therapeutic procedure, consider placing a feeding tube at that time. Prophylactic placement of a feeding tube can provide a safety net when it is unclear whether an animal will begin eating on its own. In cases in which an animal has intractable vomiting, severe malabsorption, or neurologic disorders in which a gag response is compromised, parenteral nutrition is the preferred route of nutritional support. Information on parenteral nutrition is available from other resources.^14,15

Depending on how long the animal was anorectic, feedings should provide 25% to 50% of RER on the first day, divided into four to six feedings (although most animals can tolerate four feedings a day), with each feeding administered over at least 10 to 15 minutes. As long as the animal tolerates the feedings, the amount fed can be gradually increased to achieve 100% RER over two to four days. In our clinical experience, most animals tolerate volumes between 5 to 20 ml/kg per feeding. When sending the animal home, it is best to adjust to three feedings a day, if possible, to aid in owner compliance.

Feeding hospitalized animals by continuous-rate infusion is appropriate for those that do not tolerate bolus feeding (e.g. delayed gastric emptying, ileus).

Diet

All enteral diets should be refrigerated after opening and should be discarded after 48 hours since contamination can occur. Enteral diets should then be warmed to room temperature before administration to the patient. Choosing the most appropriate diet depends on several factors, including the animal's medical condition and nonpatient factors such as the tube type, diet availability, and cost.

For patients with small-bore tubes (NE, NG, J tubes), a liquid enteral diet must be given. One liquid enteral diet that meets nutritional requirements for dogs and cats is CliniCare Canine/Feline Liquid Diet (Abbott Laboratories). For cats with underlying renal disease that require decreased protein and phosphorus or for dogs requiring phosphorus restriction but minimal protein restriction, CliniCare RF Feline Liquid Diet (Abbott Laboratories) is a better choice; however, this product provides too much protein for a dog that requires significant protein restriction.

Not all enteral diets marketed for dogs and cats are nutritionally complete and balanced, so they should be evaluated carefully to ensure that they meet the Association of American Feed Control Officials minimums for all nutrients before use.

Some liquid enteral diets for people (e.g. Ensure—Abbott Nutrition, Peptamen—Nestlé HealthCare Nutrition) can be used short term in dogs, but these diets do not provide complete and balanced nutrition and modifications are necessary if they are to be given for more than a week. When human enteral products are given to dogs and cats in the short term, additional protein, B vitamins, arginine, and taurine is almost always required, and calcium, zinc, iron, and choline supplementation is almost always required for long-term administration of these products. However, the specific nutrients and amounts that need to be supplemented vary with each product. A board-certified veterinary nutritionist can assist you in selecting (and modifying, if necessary) the most appropriate enteral product for your practice.

Table 2: Nutritional Assessment of Available Veterinary Critical Care Diets

When these critical care diets are contraindicated for an individual animal (e.g. a dog with advanced kidney disease or a cat requiring a novel ingredient diet), commercial canned veterinary diets may be given for enteral feeding if liquified by adding water and using a high-speed blender for two or three minutes. The amount of water added to each diet varies based on the individual diet, but the resulting caloric density is typically well below that of critical care diets (e.g. 0.5 to 1.2 kcal/ml). Additionally, these diets require careful flushing to avoid tube clogging.