Feeding tube options (Proceedings)

Nutritional needs of the anorectic or debilitated animal are sometimes overlooked, since most of the focus is placed on curing the disease and not the whole patient. Nutritional support can provide the energy the body needs to help combat disease. Diets are now being formulated to meet the caloric requirements of the individual patient depending on such factors as disease process, age, caloric requirements, and route of ingestion. While one canine patient in kidney failure might require a protein restricted diet, another might require low fat diet. Most of these formulated diets, while nutritionally appropriate, are not palatable to the patient. So here's the dilemma--how do we feed our patient their correct diet if they are not willing to eat it?

Dietary stimulants such as cyproheptadine and mirtazapine are an option, but only offer temporary support and are minimally effective, especially in the anorectic animal. TPN (total parenteral nutrition) or PPN (partial parenteral nutrition) can be very costly and can lead to catheter-related infections. Force feeding is not recommended--most of the food ends up on the floor or on you instead of in the patient. Patients can also become fractious after several feeding attempts.

Feeding tubes offer the most options for nutritional support. There are many factors to take into consideration when choosing a feeding tube in regards to the patient -

• Does the patient have a functional gastrointestinal tract?

• How long will the patient need the feeding tube?

• Will the animal's temperament allow for a feeding tube?

• Will the owner be able to maintain and use the feeding tube at home?

One more factor to consider is risk of anesthesia. Your patient may need to be stabilized before a feeding tube can be placed. This may take several days. In the interim, a short-term option such as a nasoesophageal tube (if not vomiting) or TPN can be implemented.

The material that your feeding tube is made of is very important. Gastric juices can render some tubes brittle and stiff. Tubes that are too flimsy or thin may burst if too much pressure is applied. Silicone catheters are usually the best option, and can withstand the abdominal environment. Latex is another good option. Latex tubes create a reaction on the skin, allowing a stoma to form and making it easier to replace if needed. Latex tubes can discolor and break in the presence of digestive juices and should be removed and/or replaced after about 12 weeks. Red rubber feeding tubes (Sherwood Medical) are used frequently at the VMTH, especially for esophagostomy tube placements. These tubes can also discolor and turn brittle and should be monitored closely and replace if needed.

Outer diameter of feeding tubes is dependent on where the tube will be placed and the size of the patient. Keep in mind that the bigger the diameter, the easier it will be to get the food into the patient. Tubes are measured at the outer diameter using the French (fr.) unit which is equivalent to 0.33 mm per unit.

Nasoesophageal tube placement

These tubes are for short-term use, the simplest to place, and require only topical anesthetic. Only a liquid diet may be used through these tubes. A functional nasal cavity and GI tract are necessary for these tubes to work properly. A gag reflex must also be present to prevent reflux. Small diameter catheters such as 5 or 8 fr. infant feeding tube or red rubber catheter work well for this procedure. Additional materials needed are Proparacaine ophthalmic drops, Lidocaine jelly, tape, and either suture, tissue glue or staples to secure the tube.

Procedure

• Place 2-3 drops proparacaine into the nasal cavity about 3 minutes apart.

• Measure your tube from the tip of the nose to the ninth rib and mark with a piece of tabbed tape. This will prevent the tube from entering the stomach and causing GI reflux.

• Lubricate the distal end of your tube with Lidocaine jelly.

• With the patient's head in a normal position, gently direct the tube in a ventromedial direction into the nasal cavity. The tube should move easily into the esophagus. If you encounter any resistance, retract the tube and try again.

• When the tube is placed with the mark on the tube at the tip of the nose, secure the tube first near the nostril, then either above the eyes on the forehead or on the side of the face below the ear. You may need to shave a small area to adequately secure the tube to the skin.

• To check positioning, there are several options-

      o Inject 5 ml. of air through the tube while auscultating the stomach and listening for gut sounds.

      o Inject 3-5 ml. of saline through the tube. If the patient coughs, this could indicate that the tube might be in the trachea.

      o Performing a lateral thoracic radiograph.

Esophagoscopy tube placement

Esophagostomy tubes are the most common feeding tube we place/use at the VMTH. The procedure takes about 15 minutes and requires general anesthesia. The tube's larger diameter allows for well-blended food and/or crushed medications to be used. Red rubber catheters are used most commonly for this procedure. For cats and dogs the sizes can range from 14 fr to 18 fr depending on the size of the patient. Large breed dogs can usually accommodate a 24 fr. latex tube. Other materials needed are a small suture set with #11 scalpel blade, skin suture, mouth gag, sterile gloves and drape, and an appropriate sized right-angled forcep such as a Kantrowicz or Mixter. These tubes can be replaced after about 6-8 weeks, providing a stoma tract has been formed. Indications for utilizing the esophagostomy tube include chronic kidney disease, fatty liver disease, and trauma to the oral cavity.

Procedure

The esophagostomy tube is most commonly placed on the left side of the neck, since the esophagus lies slightly to the left of midline. Once the patient is anesthetized and in right lateral recumbency, shave and surgically prep a small area on the cervical region, starting from the left side of the trachea. Your tube should also be premeasured from the midcervical esophagus to the 8th rib and marked with a permanent marker to ensure correct placement within the esophagus. With a mouth gag in place, gently slide the right-angled forceps through the mouth and to the midcervical esophagus. The tips of the forceps should be pointed up and be visible under skin, avoiding critical areas such as the jugular vein. Incise the skin and esophageal mucosa over the tips of the forceps. Open the forceps and place the end of the feeding tube into the forceps. Withdraw the forceps, being careful not to scrape the tips across the esophageal mucosa. Unclamp the forceps from the tube and cut off the tip of the red rubber catheter to make the diet flow through the tube easier. The tip of the catheter can now be gently fed back into the esophagus, and at the same time slowly pulling out the other end until the tube is facing caudally with the feeding end of the tube facing cranially. The tube should be able to move freely at this stage, with no internal kinks or bends in the tube. Be sure your pen mark is visible at the level of the skin. Use retention sutures, such as a Chinese finger-trap suture, to hold the tube in place. A lateral radiograph should be taken to confirm that the tube is not in the stomach. Place an adapter on the end of the tube to keep food from coming out. A sterile gauze pad can be placed at the stoma site and gauze wrap should be placed loosely around the neck. Patients should be watched carefully post-anesthesia for difficulty breathing, which could indicated that the bandage is too tight. The stoma site should be observed and the dressing changed daily. Replace the tube by placing a guide wire through the old tube, removing the tube and thread the new tube down the wire and resuture.

Gastrostomy tube placement

These tubes are reserved for those patients who will require long term nutritional support. Indications include megaesophagus, myasthenia gravis and chronic kidney disease. The large diameters (20 fr for cats and smaller dogs, 24 fr for dogs) allow for blended pet foods with medications. These tubes are placed in the body of the stomach and exit out the left side of the patient, usually in back of the rib cage. It is recommended to surgically place a gastrostomy tube in patients over 30 kg., since the heavier abdominal wall tends to "slip" off of the tube and could lead to food entering into the peritoneal space.

Specialized tubes are required for this type of placement. The distal end of the tubes must have a wide tip, or bumper, so as to not pull out of the stomach. The Mushroom and Pezzer type catheters also have 3 eyes to make feeding easier. These tubes also have a loop of suture at the top and come with a clamp, as well as an external flange that sits at the stoma site. These tubes may be purchased as a kit or individually.

Gastrostomy tubes can be placed either percutaneously or surgically. A PEG (Percutaneous Endoscopic Gastrostomy) tube technique refers to the placement of a tube endoscopically. Materials for this procedure include a suture set, 1-0 and 2-0 or 3-0 nylon, mouth gag, 18g needle or catheter, lubricating jelly, sterile gloves and prep, and surgical blade.

Procedure

The anesthetized patient is placed in right lateral recumbancy. An endoscope is placed into the stomach. The stomach is insufflated and an optimal site for placement on the body wall is selected by digitally palpating the left side just below the ribs. A small incision is made through the shaved and surgically prepped skin. An 18 g. needle is then pierced through the incision and into the stomach, making sure that any vital organs are not in the needle's path. A 1-0 nylon suture is threaded through the needle and into the stomach. The suture is grabbed with a biopsy forcep and the endoscope with forceps is removed. The suture is then attached to the tube. The needle is removed from the suture and the suture is pulled out at the skin incision, moving the tube into the stomach and against the wall. The skin incision may need to be widened to accommodate the tube. Correct placement is checked with the endoscope making sure that the mushroom tip is against stomach mucosa. The external flange is then placed against the skin, the clamp is placed in the center of the tube and a feeding adapter is placed on the end. The tube can be sutured to the skin using tabbed tape. A stockinette and e-collar are also recommended.

BPG (Blind Percutaneous Gastrostomy) technique utilizes a rigid tube that is passed into the stomach, pushed tightly up against the stomach mucosa, with a needle pierced through the skin and into the placement device. A wire is then placed into the needle and out the other end of the device. The device is then removed and a tube is attached to the wire and pulled into the stomach.

Gastrostomy tubes can be replaced with a Low Profile Gastrostomy Device, or LPGD. These tubes lie relatively flat against the skin and are therefore more comfortable and better tolerated than the longer tubes. These devices contain an anti-reflux valve that keeps the food from leaking out of the tube. LPGDs can last for several years. They can be easily replaced with just sedation.

Client education is a key factor in properly maintaining these feeding tubes. A client handout and feeding demonstration should be included with every patient. Vital information should include how to maintain the tube, how much to feed and what to do if the feeding tube is somehow removed.