The cardinal rule of feeding a malnourished or anorectic patient is "use the gut if at all possible."
The cardinal rule of feeding a malnourished or anorectic patient is "use the gut if at all possible." This is a tricky proposition in cats who seem more prone to anorexia than dogs as a result of stress (at home or in hospital), finicky eating behaviors and dietary preferences, and the important role of odor and texture in feline appetite. When these factors are added to an ill cat experiencing nausea, vomiting, diarrhea, malaise, pain or lethargy, it becomes a challenge to keep these patients at an appropriate plane of nutrition. Yet studies have shown that nutrition plays a key role in the full recovery of critically-ill patients. Enteral feeding techniques preserve the mucosal barrier, prevent villus atrophy, help maintain the immunologic function of the GI tract, and can allow owners to treat their pets at home.
Types of feeding tubes
Nasoesophageal tubes (NE tubes)
Require no anesthesia except local lidocaine or proparacaine. These tubes are most appropriate for short-term nutrition in cases where animals are simply anorexic, but not vomiting. The size of the tube limits the type of diet to liquid forms. Radiographs of the chest will confirm that the tube has not been advanced through the lower esophageal sphincter (LES) as this can cause discomfort, esophageal reflux and/or vomiting in the cat, thereby increasing the risk of aspiration. Care must be taken to insure that the tube has not been threaded inadvertently into the trachea prior to administering the diet. A small amount of sterile saline can be injected into the tube and if a cough is elicited, it is safest to replace the tube. The lack of a cough does not completely rule out tracheal placement and therefore is another good reason for post-procedure radiographs. Despite being sutured in place, some cats manage to pull the tube or can vomiting the tube into the mouth where they can chew and swallow the pieces. While an E-collar can be used to prevent this, such measures can be additional stressors that decrease the likelihood the cat will begin to eat on its own.
Esophagostomy tubes (E-tube)
Require a short general anesthesia, but can be placed easily and without the need for special equipment or expertise. A larger bore tube, such as a 16 – 18 French red rubber feeding tube allows for the use of blended diets. As with the nasoesophageal tube, placement should not extend into the stomach past the LES. The red rubber tubes do not usually have a radiodense strip within them but can still be visualized on plain radiographs or with the infusion of contrast material. Vomiting patients are not ideal candidates for E-tubes because the same potential for aspiration exists as with the NE-tube. The owner can easily care for the tube at home and must be instructed to clean the stoma site daily. One retrospective study identified stomal infections/abscesses as the most common complication. Others included swelling of the head from tight bandaging and vomiting the tube into the oral cavity.
Percutaneous Endoscopic Gastrostomy (PEG) tubes
Although these tubes require some additional expertise and endoscopic equipment, they are especially suited for the anorectic cat that is also vomiting. Although the tube can be placed blindly, the endoscopic method allows for visualization of the site before and after placement to ensure that the tube is in the correct position and suitably snug against the stomach wall, without be so tight as to cause pressure necrosis. The tube can remain in place for many months, but needs to be in place for at least 10-14 days before it can be removed to allow time for stomach adhesion to the body wall. Removing the tube too soon after placement and before full adhesion is established can allow the stomach wall to fall away from the body wall and allow gastric contents to leak into the peritoneum. Therefore, we recommend a single suture that is passed from the skin, into the gastric lumen and then back out to the skin. This gives additional insurance that, should the tube become dislodged, and the stomach is more likely to stay up against the body wall, thereby decreasing the risk of peritonitis. Complications include peritonitis and stoma cellulitis/abscessation.
One study comparing the PEG tube to the E-tube found no significant differences in complication rates, ease of owner use and maintenance of body weight. Though not statistically significant, patient removal of the tube occurred in a greater number of cats with E-tubes compared to the cats with PEG tubes.
Jejunostomy tubes and PEG-J tubes
Jejunostomy tubes are generally placed surgically and therefore beyond the scope of this presentation. J-though-G or PEG-J tubes, although still requiring anesthesia, can be placed endoscopically and have the benefits of allowing for gastric content management (such as suctioning) and post-gastric feeding, especially helpful in cases of pancreatitis. Should post-gastric feeding no longer be necessary, but the patient continues to need enteral nutritional support, the J-tube can be pulled while the PEG tube remains in place for gastric feeding. Variable methods exist for the endoscopically-placed tubes. Despite being non-invasive, more expertise is required compared to the placement of the PEG tube only. The primary complication of the PEG-J tube is retrograde migration of the J-tube and diarrhea from alimentary liquid diets.
Cats with unexplained anorexia without vomiting or oronasal disease that requires short-term nutritional support can be managed with NE or esophagostomy tube. In the case of nasal disease, an NE tube can be difficult to place and an esophagostomy tube is preferred. Patients with esophageal disease (motility disorders, megaesophagus, esophageal strictures or esophagitis) are best managed by by-passing the esophagus and feeding directly into the stomach via a PEG-tube. If an animal is vomiting, esophageal and NE tubes should be avoided because of the potential for vomiting the tube into the oral cavity, chewing/swallowing a portion of the tube and creating the potential for pyloric or small intestinal obstruction. If a disease needs to be managed long-term (IBD, neoplasia, severe hepatic lipidosis or cholangiohepatitis or oral neoplasia), PEG-tubes are the wiser choice. Finally, with gastric-emptying disorders, bile duct obstruction and pancreatitis, PEG-J tubes (or surgically-placed J-tubes) provide the best means of enteral nutrition. A few of the following case scenarios will be discussed as time allows:
For any cat that has been anorexic for 3-5 days, aggressive enteral nutrition should be considered. The type of enteral feeding tube chosen depends upon the severity of illness, the estimated duration of therapy, the stability of the patient to undergo an anesthetic procedure, the presence of esophageal disease or vomiting and the ability of the owner to manage the tube properly at home.
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