Nutritional management of convalescing cats

Nutrition is an important therapeutic intervention in the management of critical care patients¹. During illness hormonal and cytokine changes interfere with the normal adaptive responses to a reduced caloric intake. Thus, energy requirements are not down-regulated, and a metabolic shift also causes preferential use of body protein rather than fat to meet ongoing energy demands¹.

ENERGY STORAGE LOSSES DURING FASTING	% ENERGY IN CANINE AND FELINE CN

The consequent protein-energy malnutrition (PEM) that results can have many adverse consequences including:
Impaired immune responses Hypoproteinaemia Anaemia	Delayed healing Muscle weakness Increased morbidity and mortality

Early patient identification for nutritional support minimises PEM consequences. The following are generally recommended as indicators of patients that require support^1,2:

• Anorexia for 3-5 days (cats have very limited glycogen stores and are unable to down-regulate activity of hepatic transaminases that catabolise protein).
• Recent unintentional loss of >10% body weight.
• Inadequate/poor lean body weight.
• Serious underlying disease (e.g., severe trauma, peritonitis, pancreatitis, major surgery).
• Direct protein loss (e.g., protein losing enteropathies, draining wounds).
• Poor wound healing, hypoalbuminaemia and lymphopenia.

Wherever possible, it is strongly recommended that enteral nutritional support is used (voluntary food intake or tube feeding) as this has many benefits over parenteral support^1,2.

Concurrent problems such as nausea, vomiting and pain should be addressed before offering food to the patient to avoid inducing food aversion.

The aim of enteral nutritional support is generally to meet the patient's full caloric requirements within 2-3 days of initiating therapy. If the animal has had prolonged anorexia, a more gradual increase may be required.

Energy requirements are based on estimation of the Resting Energy Requirement (RER):

RER (kcals/day) = 70 x (actual bodyweight in kg)^0.75

This calculation provides a reasonable estimate of RER and avoids complications associated with over-feeding. If body weight is not being maintained an upward adjustment may be needed^1,2.

• Voluntary intake is ideal using a highly palatable food, warmed if necessary.
• Pharmacological appetite stimulation can be used judiciously, but care should be taken to monitor the response to therapy.
• Tube feeding via naso-oesophageal, oesophagostomy, or gastrostomy tubes. In some situations a jejunostomy tube may also be valuable.

Canine and Feline CN provides:

• An energy dense, high protein and high fat diet which is preferred for most cases requiring nutritional support.
• A highly palatable diet designed to meet the increased needs of cats.
• A diet that can readily be used with larger diameter feeding tubes (oesophagostomy and gastrostomy).
• When blended 1:1 with water, CN provides 0.55 kcal/ml and will readily pass through feeding tubes = 9FG. For smaller tubes the mixture must first be passed through a fine sieve.
• A diet supplemented with specific nutrients (omega-3 fatty acids, vitamin A and E, zinc and arginine) to help provide optimum nutritional support.