Page 425 - Small Animal Clinical Nutrition 5th Edition

Chapter
25

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Critical Care Nutrition and

Enteral-Assisted Feeding

Korinn E. Saker
Rebecca L. Remillard

“Let food be your medicine and medicine be your food.”
Hippocrates

function, antibody affinity and cytokine production (Shikora et
CLINICAL IMPORTANCE
al, 1994; Chandra, 1992; Redmond et al, 1991). Although
Patients of any age may become malnourished from inade- fewer studies are available for review, similar alterations in the
quate nutrient intake. Malnutrition is any disorder with inad- immune system are seen in pets with insufficient caloric intake
equate or unbalanced nutrition associated with either nutri- (Freitag et al, 2000; Simon et al, 2000). Studies have shown that
tional deficiencies or excesses. By most estimates, many hos- protein deficiencies that limit amino acid and nucleotide sub-
pitalized people and companion animals do not receive ade- strates for cell proliferation result in reduced numbers of circu-
quate nutrition. Hospitalized veterinary patients are more lating T-lymphocytes, helper cells and suppressor cells
commonly malnourished due to decreased total food intake. (Chandra and Kumari, 1994). Malnutrition also decreases
The major consequences of malnutrition in all patients, but immune function of existing cells through reduced complement
more prominently in sick or injured patients, are decreased secretions, less effective macrophage function and decreased
immunocompetence, decreased tissue synthesis and repair killer cell activity (Saxena et al, 1984). Cytokine production and
and altered drug metabolism. release are independently impaired in protein-calorie malnutri-
tion and in several micronutrient (zinc, iron, pyridoxine, vita-
Immunocompetence min A, copper and selenium) deficiencies (Meydani, 1990;
The reciprocal relationship between nutrition and immunity Chandra, 1992a).
has been recognized for centuries. A malnourished patient is Numbers of T helper cells and T cytotoxic suppressor cells
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more susceptible to infections and a septic patient is more like- in malnourished people return to normal quickly with refeed-
ly to be anorectic, which results in malnutrition. Nutrient ing (Chandra, 1983). Immunoglobulins and circulating anti-
imbalances suppress immune function, which increases the risk bodies are maintained at relatively low levels during malnutri-
of disease; conversely, certain diseases alter some nutrient tion, but are highly responsive to appropriate refeeding stimuli.
requirements (Semba et al, 1997; Burkholder and Swecker, For example, investigators measured serum globulin concentra-
1990). Decreased protein-calorie intake is the most common tions in 12 healthy beagles before and 24 hours after small
cause of secondary immunodeficiency in people and can cause bowel resection. All dogs were fed via gastrostomy tube imme-
progressively poorer responses in several components of the diately after surgery. Six dogs received a monomeric food
immune system including significantly impaired cell-mediated whereas the other six were fed an electrolyte solution. Twenty-
responses,secretory IgA production,phagocytosis,complement four hours postoperatively, the dogs fed the monomeric food