Page 651 - Fluid, Electrolyte, and Acid-Base Disorders in Small Animal Practice

638 SPECIAL THERAPY

gastritis, enteritis, or colitis without producing additional
irritation. The choice of an appropriate diet for a given
patient depends on the route chosen and any disease-
related nutrient modifications. Injured or diseased
animals should not lose weight while being fed the diet
D
at the recommended dosage. Patients with orogastric
or gastrostomy tubes can be fed by measured amounts
of an appropriate canned food pureed with water in a
blender to the desired consistency.
Numerous commercial products are available for
enteral support, most falling into one of two groups.
The first group includes polymeric diets for use in patients
P S with nearly normal gastrointestinal function. These
products contain casein, soy, or egg albumin as protein;
medium- or long-chain triglycerides as fat; glucose
polymers as carbohydrates; and vitamins and minerals.
Nutrients are provided in high-molecular-weight forms
Figure 26-15 Fluoroscopic image of a recumbent dog showing to maintain osmolality at approximately 350 mOsm/
the correct placement of the nasojejunal tube with the distal tip in kg. These products also are low in lactose and residue.
the jejunum. D, duodenum; P, pylorus; S, body of the stomach.
Defined-formula diets, the other major group, are
those modified to accommodate disease-associated
limitations on nutrient intake. Peptide and “elemental”
Indwelling NJ tubes can cause rhinitis, esophagitis, diets essentially are predigested forms of the polymeric
reflux, and dacryocystitis several days after placement diets, which are recommended for use with enterotomy
but no more than is expected for nasoenteric tubes. Other or jejunostomy tubes (nasojejunal or J through G tubes).
concerns include retrograde movement of the tube into However, a recent study evaluated the short-term use of
the stomach or esophagus. Retrograde movement can polymeric diets (such as Clinicare) (Figure 26-16) and
occur spontaneously or be associated with vomiting, found no difference in outcome or incidence of diarrhea
but is least likely to occur when the tube is advanced when compared with Peptamin. 10 In defined-formula
far into the proximal jejunum. In one study evaluating diets, the protein is present in the form of peptides or
fluoroscopic NJ placement in dogs, 17 of 20 tubes that amino acids, and carbohydrates as oligosaccharides or
were advanced into the jejunum remained in place until monosaccharides. These usually are low in fat, and many
intentional removal. Reported complications included have a portion of the fat present as medium-chain triglyc-
bile leakage from the externalized opening of the tube, eride oil to enhance absorption. The osmolality of these
retrograde movement of the tube if the tube was placed solutions may be higher (450 to 850 mOsm/L) than
proximal to the caudal duodenal flexure, sneezing, and meal replacement formulas because of the inclusion of
nasal discharge. 100 When the tube is no longer necessary, small-molecular-weight nutrients. These diets have been
it is removed without sedation by gentle traction. recommended for patients with abnormal gastrointestinal
Patients should be fed through the gastrointestinal function (e.g., severe inflammatory bowel disease or pan-
tract whenever possible; however, some patients are not creatic insufficiency). 57 Other defined diets have been
candidates for enteral nutritional support. Animals that marketed for impaired hepatic, renal, and respiratory
are vomiting or regurgitating, who cannot be controlled function, and for stress. The efficacy of these formulas
with pharmacologic agents; those with adynamic ileus of has not yet been completely established. 89,91
the small intestine, intestinal obstruction, or severe A third class of enteral product is the feeding module.
mucosal disease; and those that cannot guard their respi- These products are concentrated sources of one nutrient
ratory tract should be fed parenterally (see Chapter 25). (i.e., protein, fat, or carbohydrate). Modules may be
added to increase specific nutrient concentrations or to
DIETS reduce the required volumes. They also may increase
the osmolality of the formulation. In the past, when using
Enteral diets for nutritional support should be palatable, a human enteral product, we supplemented diets
easily digested, readily assimilated, efficiently used with a containing 17% of the kilocalories as protein, with 5 g
minimum of metabolic waste products, and easy to protein powder (ProMod) per 8 oz diet for all cats with
deliver. Box 26-5 presents criteria for selection of an normal protein needs, and for dogs with increased pro-
appropriate diet. 89 The ideal oral food for anorexic tein needs. Commercial nutritional products for humans
animals should be so well tolerated by the gastrointestinal are available at large public and hospital pharmacies, or
mucosa that it can be administered to patients with manufacturers may be contacted for local availability.