The feeding schedule

Estimating a patient's approximate caloric requirement is important because feeding more of any food than is necessary may cause metabolic complications (acidosis, electrolyte shifts) and overfeeding patients through a feeding tube is possible. Diseased patients have metabolic rates and energy requirements that are less than those of comparable healthy individuals.

Requirements for all other nutrients need not be calculated when the food is "complete and balanced." When the patient consumes the proper amount of balanced food calories, all other nutrient requuirements have been met, unless known losses of particular nutrients occur (e.g., protein and electrolytes).

Calculate the RER using the current body weight because feeding for weight gain will be overfeeding a sick patient. The formula to estimate the RER of a hospitalized patient is:

RER = 70(BW_kg)^0.75 , or simply 15 kcal/lb dog, 20 kcal/lb cat and 25 kcal/lb of either under 5 lbs. Most hospitalized veterinary patients should be fed at their calculated RER, realizing their actual energy requirement is likely to change over the course of the disease process and recovery.

In fact, in human surgical patients, there was relatively little additional benefit to increasing intake after half of the RER requirement had been achieved. And while there are a few exceptions, initially feeding patients at RER, or slightly greater than 50 percent of RER, is a good recommendation that decreases the probability of complications. It is logistically easier to accomplish and still derives benefits of nutritional support. Feeding is preferable to starving, yet underfeeding is preferable to overfeeding.

The feeding schedule often is determined by the patient's ability to tolerate food and the logistics of feeding. Feeding an amount equal to the patient's RER during the first 24 hours of food reintroduction, if physically tolerated, is recommended. The stomach does not "shrink" during a prolonged fast, but rather the stretch receptors are more sensitive and are stimulated by a smaller volume during refeeding.

If the volume of food required to meet RER in 24 hours is not tolerated by the stomach, feeding one-third of RER and then increasing the amount by one-third every 24 hours is a more cautious approach.

Foods should be warmed to room temperature, but not higher than body temperature before feeding, and boluses must be infused slowly (over approximately 1 minute) to allow stomach expansion. Daily food dosage should be divided into several meals according to the expected stomach capacity. Gastric capacities for cats and dogs are typically 5 to 10 ml/kg body weight during initial food reintroduction after a prolonged period of no food intake.

Salivating, gulping, retching and vomiting may occur when too much food has been infused or when the infusion rate is too fast.

Some patients cannot tolerate bolus feeding to the stomach, but they benefit from a slow, continuous-rate infusion (CRI) administration (by pump or gravity flow) of a homogenized liquid food to the stomach. Ideally, homogenized liquid food should be administered through the tube using a slow, continuous drip delivered by a pump.

Foods administered through a J-tube also must be infused slowly and often in either very small quantities or by a slow gravity drip or enteral pump with an hourly rate equal to RER/24 hours because the jejunum is volume-sensitive. The patient's daily fluid requirement must be met, and additional water may be administered through the feeding tube to meet that requirement. Liquid oral medications can be administered easily through feeding tubes and then flushed. If meal feeding, each must be followed by a water-flush to clear the feeding tube of food residue. When the patient is volume sensitive, it is important to know the minimum volume required to flush the tube.