MANAGEMENT OF FEEDING TUBES
The care of enteral feeding tubes is critical for their success. The first step is keeping tubes securely in place with sutures.
A light bandage should be used to cover all E, G, and J tubes. The tube site should be checked daily for redness, swelling,
and discharge as well as for tube displacement. Drawing a line with a permanent marker at the insertion site on an E or a
G tube allows owners to monitor for tube displacement at home. NE and E tubes may become malpositioned if the animal vomits.
Displacement or early removal of a G or J tube constitutes a surgical emergency if it occurs before a strong stoma forms because
food or gastrointestinal contents will leak into the peritoneum.
Exercise caution when administering medications through feeding tubes as they may not be compatible with enteral formulas
or may clog the tube.16,17 Some medications should not be crushed (e.g. chemotherapeutic agents, extended-release tablets) or removed from capsule form (e.g. enteric coated). Some medications have better bioavailability when administered with food while others should be administered
on an empty stomach.
Feeding tubes are typically well-tolerated, but complications can arise and are characterized as mechanical, metabolic, or
gastrointestinal.16,18,19 They are minimized by providing good instructions and careful monitoring.
Mechanical complications include tube clogging, inadvertent removal of tubes, and tube migration. To reduce the risk of tube
clogging, a few precautions should be taken. Only liquid enteral diets should be administered through small-bore (< 10-Fr)
tubes. Canned diets should be blenderized thoroughly (at least two or three minutes in a blender) before administering them
through E or G tubes. Crushed tablets should not be administered through small-bore tubes.
Tubes should be flushed well with room temperature water before and after food and medication administration. Depending on
the size, tubes generally require between 3 and 10 ml of water to adequately flush them. If a tube does clog, inject a solution
of ¼ teaspoon pancrelipase plus 325 mg of sodium bicarbonate in 5 ml of warm water, let it sit for five minutes, and then
flush the tube with water.20 Keeping the tube capped between feedings will also help prevent clog formation.
To prevent the inadvertent removal of tubes, E-collars and bandages or stockinets should be used.
Inadvertent food aspiration can occur because of underlying disease (e.g. megaesophagus), inappropriate tube placement, or the migration of tubes. Tube placement should be confirmed radiographically
before the first feeding. Some clinicians recommend techniques to help ensure proper tube placement before feeding, such as
aspirating the tube before each feeding to test for negative pressure or injecting a small amount of saline solution into
the tube. However, further studies are needed to determine whether these measures provide additional safety benefits. Animals
at risk for aspiration should be fed in an upright position.
Potential metabolic complications include overhydration, electrolyte disturbances, and refeeding syndrome. Concurrent intravenous
fluids must be adjusted when initiating enteral feeding to account for the water volume provided by the food and for multiple
flushes, which can greatly contribute to daily water intake.
Refeeding syndrome, which results in hypophosphatemia, hypokalemia, and hypomagnesemia, is most likely to occur in animals
that have not eaten for marked periods. In patients that have been anorectic for more than a week, feeding should be initiated
slowly (25% to 33% on day 1 and progress over three or four days) and electrolytes should be closely monitored during the
first 12 to 72 hours after initiating feedings.21
Refeeding syndrome can have serious consequences, but incidence rates for this complication are not well-documented. One study
reported that 2.5% of cats receiving parenteral nutrition developed refeeding syndrome,22 and another study of 46 dogs fed by nasoenteral tube reported that none developed refeeding syndrome.23 However, it is important to note that most studies of enteral and parenteral nutrition do not specifically assess the rates
of refeeding syndrome but more commonly report individual electrolyte abnormalities. For example, a retrospective study of
cats receiving enteral nutrition reported that 2% of cats developed hypophosphatemia,24 while retrospective studies of parenteral nutrition in dogs and cats report rates of hypophosphatemia between 0% to 28%.25-29
Gastrointestinal complications may include vomiting, diarrhea, or abdominal discomfort. Antiemetic therapy may have some benefit
and was recently reviewed,30 but feedings may need to be adjusted (e.g. decrease volume, increase frequency, change of diet). Changing to a lower-fat diet may benefit some animals but will often
result in feeding an increased volume of food.