Page 636 - Fluid, Electrolyte, and Acid-Base Disorders in Small Animal Practice

CHAPTER • 26

Enteral Nutrition

Melissa L. Holahan, Sarah K. Abood, Mary A. McLoughlin, and C.A. Tony Buffington

NUTRITIONAL ASSESSMENT be broken down more quickly than adipose tissue, the
body condition may appear normal when an overcoat
Identification of patients needing nutritional support of fat is covering a malnourished animal. These patients
requires a thorough history, physical examination, and usually can be recognized by their poor hair coat quality,
evaluation of laboratory data. A diet history is obtained abnormal prominence of the bones of the head, and by
to ascertain the quality, total daily intake, and appropri- palpation.
ateness of the diet fed (Figure 26-1). Identify current Many biochemical and hematologic abnormalities may
drugs the animal may have been prescribed (e.g., occur during prolonged anorexia, 62 including
corticosteroids, antibiotics, diuretics, cancer chemother- hypoalbuminemia, lymphopenia, and anemia, but they
apeutic agents), as these drugs can affect nutritional are notspecific “markers ofmalnutrition.” Serumalbumin
homeostasis. To assess the need for nutritional support, concentration often is decreased in patients secondary to
the medical history includes inquiries about: involuntary increased permeabilityofthe vascularendothelium, aswell
weight loss, voluntary dietary intake, and presence of as to decreased synthesis (or increased degradation) rates.
persistent gastrointestinal signs. Historical information Serum albumin concentration also is affected by hydration
suggestive of malnutrition includes rapid weight loss status and the presence of gastrointestinal, hepatic, or
(greater than 10% of usual body weight); recent surgery renal disease. 51 Lymphopenia caused by malnutrition,
or trauma; and increased nutrient losses from wounds, stress, or immunosuppressive drugs. Starvation may inter-
vomiting, regurgitation, diarrhea, or burns. Infection, fere with immune competence even when the total lym-
trauma, burns, and surgery can increase nutrient needs, phocyte count remains within the normal range. 21
whereas prolonged use of antinutrient or catabolic drugs The main objective of nutritional assessment is to iden-
may result in nutrient depletion. The number of days an tify malnutrition as an independent problem. If not pres-
animal has not consumed adequate calories (hyporexia or ent initially, the animal should be periodically reevaluated
complete anorexia) before hospitalization may be during hospitalization to ensure that malnutrition does
determined from the history. not develop secondary to an ongoing disease process,
Physical evaluation begins with the assignment of a drug therapy, inability to eat, inappetence, or food depri-
body condition score, 14 ranging from 1 (cachexic) to 5 vation. 15 Nutritional support should be instituted in mal-
(obese), with 3 being normal (Table 26-1). Other scoring nourished patients and in those for which voluntary food
systems have been developed for dogs and cats. 59,60 intake is impossible for prolonged periods. 2
Underweight and malnourished animals often have a
body condition score less than 3 out of 5 because of loss EVIDENCE FOR EARLY
of muscle mass and subcutaneous fat. Thin, dry skin, hair ENTERAL NUTRITION
that is easily epilated, pressure sores, and poor wound
healing may be seen, indicating the body has redirected Numerous studies in human medicine have demonstrated
its nutrient resources to support visceral protein synthesis multiple benefits to the early initiation of enteral nutri-
at the expense of peripheral tissues. tion (EEN), including improved gut barrier function,
In patients with a condition score greater than 3 out of decreased bacterial translocation, and reduced septic
5, the possibility that an “overcoat syndrome” has devel- complications and disease severity.* Early enteral
oped must be considered. Because metabolic changes
associated with critical illness cause lean body mass to
*References 17, 37, 43, 52, 56, 67, 76, 99.

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