Abood and Buffington 1992; Marks 1998).
Each of those feeding tubes has its advantages and disadvantages. The choice of feeding tube is based on the underlying disease, the goal of the enteral nutrition, and the length of time the tube will be needed. Combination of tubes is also possible. It is not rare to combine a gastrostomy tube with a jejunostomy tube to support a patient in the short term and the long term. The jejunostomy tube will be used in the short term to support the patient in the recovery phase of the surgery, especially if the patient is vomiting, while the gastrostomy tube will be used in the long term to support the patient if still anorexic.
Enteral feeding is also very important to support the integrity of the gastrointestinal tract. The enterocytes are getting their nutrient directly from the metabolite present in the lumen of the gastrointestinal tract.
4.1 Nasoesophageal and Nasogastric Tubes
Nasogastric or nasoesophageal feeding tubes can be used in dogs and cats. Since the tubes are of a small diameter they can be advanced in the stomach without increasing the risk of gastric reflux and esophagitis (Crowe 1986; Armstrong et al. 1990a; Abood and Buffington 1991; Yu et al. 2013; Herring 2016).
4.1.1 Indications
Nasoesophageal and nasogastric tubes are mostly used for the short‐term support of a patient. It is an interesting tube for a patient that may not tolerate general anesthesia since it can be placed with only local anesthesia.
It can be used to feed a patient with a liquid diet since the tubes are of a small diameter. This tube is more efficient for small dogs and cats than for large‐breed dogs, since only liquid can be used.
It can also be used to keep the stomach decompressed or empty to prevent gastroesophageal reflux, regurgitation, and/or vomiting (Crowe 1986).
Nasoesophageal tubes are contraindicated if the patient has esophageal motility disorders. Nasogastric tubes are contraindicated for patients with esophageal strictures.
Feeding with these tubes should not be attempted if the patient is vomiting or lateral recumbent because it will increase the risk of aspiration pneumonia. However, a nasogastric tube can still be used to keep the stomach decompressed as mentioned above.
4.1.2 Materials and Equipment
Feeding tube of small diameter is required. Size 5 or 6 Fr is commonly used in dogs and cats. Polyurethane or silicone tubes are used. The tube needs to be long enough to reach the stomach. Weighted tubes can be used to facilitate their migration in the stomach (Figure 4.1). Because of the size of the tube only liquid diet can be used.
Local anesthetic mixed with a lubricant is needed to facilitate the placement of the tube. Usually 1 ml of 0.5% bupivacaine can be mixed with 1 ml of water‐soluble lubricant.
General anesthesia is not required to place a nasoesophageal or nasogastric tube. Heavy sedation might be required.
4.1.3 Surgical Techniques
Local anesthesia is applied in the ventral meatus of the nasal cavity. The extremity of a nasoesophageal tube is usually sitting in the middle of the thoracic esophagus. The length of the tube is measured from the tip of the nose to the level of the 8th or 9th rib. If a nasogastric tube is placed, it is measured from the tip of the nose to the last rib. The tube is introduced in the ventral meatus of the nasal cavity after the nares are gently pushed dorsally with the thumb while the hand is holding the head of the dog or cat. The tube is advanced and when it reaches the nasopharynx the dog or cat will start swallowing, which will facilitate the passage of the tube in the esophagus. The tube is then advanced to the desired length to reach the middle of the thoracic esophagus or the stomach (Figure 4.2).
If the patient is coughing, the tube should be withdrawn because it is progressing into the larynx and the trachea.
After placement of the tube it is stabilized on the side of the nares with a simple interrupted suture. Another suture is placed on the side of the lips and cheeks to stabilize the tube.
It is paramount that appropriate placement of the tube is confirmed before it is used to provide nutrition to the patient. Since the tubes are small it may not be possible to palpate the tube in the neck. First aspiration of the tube should generate negative pressure if it is in the esophagus or gastric content if it is in the lumen of the stomach. If air is aspirated it has been placed in the airway. If the tube is in the stomach, injection of 5 ml of air should induce borborygm, easily detected with a stethoscope placed over the stomach. Injection of 5 ml of sterile saline will induce coughing reflex if the tube is in the airway. Finally, since the feeding tubes are radiodense a lateral radiograph should confirm the accurate placement of the tube (Figure 4.2).
4.1.4 Utilization
Nasoesophageal and nasogastric feeding tubes can be used immediately to support the patient. Only liquid diet can be used. After calculating the daily calorie requirement of the patient the diet is delivered in six feedings very slowly. The tube is then flushed with saline to prevent obstruction.
The nasogastric tube can also be used to keep the stomach decompressed in case of severe ileus after abdominal surgery.
4.1.5 Tips
The administration of a long‐acting local anesthesia in the nasal cavity every four to six hours greatly improves the tolerance of the tube by the patient.
4.1.6 Complications
Nasoesophageal and nasogastric tubes can be dislodged if the patient is vomiting. Epistaxis and sneezing can occur with a nasoesophageal or nasogastric tube. Local anesthesia reduces the risk of sneezing. Nasogastric tubes may trigger gastroesophageal reflux and regurgitation. In this case it is then recommended to convert the tube into a nasoesophageal tube by pulling the tube into the esophagus. Obstruction of the tube can occur. It is important to regularly flush the tube with saline.
4.2 Esophagostomy Tube
4.2.1 Indications
Esophagostomy tubes are used to provide long‐term support to the patients. Esophagostomy tube can be maintained for several weeks to months. They are mostly used to support anorexic patients with chronic systemic disease. They are also used for patients with severe trauma to the head, after surgery of the oral cavity, or to keep the stomach decompressed (Crowe and Devey 1997a; Devitt and Seim 1997; Levine et al. 1997; Kanemoto et al. 2017).
