The two broad categories of feeding critically ill cats are enteral feeding, in which some portion of the gastrointestinal tract is utilized, and parenteral feeding, in which nutrients are administered in a manner other than using the gastrointestinal tract, most commonly via the bloodstream.
Enteral feeding is generally achieved via feeding tubes. Nasoesophageal tubes are polyurethane or silicone tubes that are inserted into a nostril. The end of the tube eventually reaches the deep end of the esophagus. The tube is anchored in place on the cat’s head using one or two stitches. An Elizabethan collar is put on the cat to prevent him from using a paw to dislodge the tube. A liquid diet can be administered through the tube. General anesthesia or tranquilization is not necessary to place a nasoesophageal tube, allowing enteral nutrition to cats who are anesthetic risks. These tubes are rarely kept in place for more than 10 days and are usually removed before the cat is sent home.
Esophagostomy tubes have become a very popular method of administering nutrition to cats requiring more long-term support. A tube is inserted into the esophagus through an incision in the cat’s neck, and threaded down the esophagus to the very end, just before it reaches the stomach. These tubes can be kept in place much longer (several weeks), for in-hospital or at-home feeding. Special liquid diets are generally not necessary — a pureed diet made from commercial pet foods can be used. These tubes are very useful in cats that are temporarily unable to eat due to disease or trauma to the nose or mouth. Placement of the tube does require general anesthesia.
Gastrostomy tubes provide nutrition by administering food right into a cat’s stomach. The tubes can be placed surgically or without surgery, through the skin using an endoscope. These tubes can provide nutrition to the cat for months if necessary.
Jejunostomy tubes are small tubes that are placed within the small intestine, usually at the time of surgery, as a way to bypass the mouth, esophagus and stomach. They are usually placed in cats with pancreatitis, as these tubes bypass the pancreas, avoiding stimulation and allowing the pancreas to heal. These high-maintenance tubes require anesthesia and surgery, followed by a liquid diet that has to be continuously pumped into the tube.
Nutrition that is delivered in ways that avoid the gastrointestinal tract completely is termed parenteral nutrition. However, it is very difficult to meet 100 percent of a cat’s nutritional requirements intravenously. Intravenous feeding used to be available only at universities, however, many veterinarians now rely on pharmaceutical companies to compound these mixtures.
Parenteral nutrition is quickly becoming a safe, convenient and economic method of obtaining an all-in-one mixture for the feline patient who desperately needs nutrition, but cannot tolerate the anesthesia necessary for tube placement, or will not tolerate a feeding tube for whatever other reason.
By Sarah Zumhofe