Placement of an enteral feeding tube is a recognized method of supportive care, and the esophagostomy tube is an accepted route that is generally well tolerated by patients and relatively easy to place. In clinical avian patients, esophagostomy tube placement has been described in parrots, raptors, and ostriches (Fig 1) (Huynh et al 2014, Aguilar et al 2012, Wynne and Stringfield 2007, Bowles et al 2006, Bennett and Harrison 1994, Honnas et al 1992).
Esophagostomy tube placement is indicated in cases of severe beak trauma or disease, as well as diseases of the oral cavity or proximal esophagus, such as abscesses and neoplasia. Esophagostomy tubes may also be used to bypass the crop in cases of severe crop trauma such as burn injury, crop laceration, or refractory crop dysfunction (Fig 2) (Aguilar et al 2012, Wynne and Stringfield 2007, Harris 2001). Esophagostomy tubes can also prove useful for proventriculotomy postoperative care (Huynh et al 2014).
Esophagostomy tubes are not recommended for regurgitating or vomiting individuals or for patients with respiratory disease.
Potential patient-related complications to esophagostomy tube placement include aspiration due to tube placement or migration into the airway, damage to cervical vascular structures or nerves, cellulitis or infection at the tube insertion site, esophageal irritation and reflux, and tube dislodgement during vomiting or regurgitation (Table 1) (Eirmann and Michel 2015, Huynh et al 2014). The tube can also be misplaced into soft tissue surrounding the esophagus (Huynh et al 2014) or it can cause trauma or even perforation of the proventriculus from the installation of an excessively long tube. Potential mechanical complications to esophagostomy tube placement include tube migration, tube obstruction, or clogging of the tube (Table 1) (Eirmann and Michel 2015).
|Table 1. Complications that occur with esophagostomy tube placement (Eirmann 2015, Huynh 2014)|
Survey radiographs may be performed post-installation to verify appropriate tube placement. A comparison on the efficacy of various solutions to dissolve clogged feeding tubes found that infusion of a solution containing 0.25 tsp. (1.25 cc) of pancreatic enzyme and 325 mg sodium bicarbonate in 5 ml warm water was most effective (Parker and Freeman 2013).
In a survey of 18 falconry birds, esophagostomy tube placement was generally well tolerated (Huynh et al 2014). Complications included unexpected removal of the tube by the patient, misplacement of the tube (into the crop), and regurgitation in two patients. In one bird, regurgitation was associated with tube placement into the crop instead of the distal esophagus. Although skin infection is a common complication in cats and dogs, no birds in the survey by Huynh et al developed such problems. A granuloma and associated skin necrosis was observed in one California condor (Gymnogyps californianus) in which ingluviotomy technique (see long-necked birds below) was used for tube placement (Aguilar et al 2012 ).
- Pre-emptive analgesia like butorphanol tartrate
- General anesthesia: inhalant anesthesia, face mask, uncuffed endotracheal tube
Silicone or polyurethane catheters (i.e. Kendall Argyle Feeding Tube, Kendall Co.) are softer and stiffen less with age than red rubber or polyvinylchloride tubes. Tube size will vary with the size of the patient; 14 French tubes can be used in large parrots and are ideal because a syringe will attach at any point where the tuber might be trimmed (Fig 3). Up to 18 Fr tubes can be placed in many medium to large raptors (Huynh et al 2014).
- Curved hemostat
- Iris scissors or scalpel blade, size 15 or 11
- Suture or acrylic glue
- White porous tape
- Male adapter plug
- Non-toxic permanent marker
- ± Cotton-tipped applicator
- ± Bandage material
- ± Restraint collar
- Place the bird under general anesthesia and intubate with an uncuffed endotracheal tube.
- Position the patient on its side, preferably in left lateral recumbency.
- Pre-measure the length of tube to be placed in the distal esophagus or proventriculus. In cats and dogs, tubes are often passed into the distal esophagus to minimize the risk of esophageal reflux and esophagitis. The tip of the tube should go approximately to the level of the fifth rib or approximately one-third of the total length of the bird (Huynh et al 2014).
- An assistant determines the volume of fluid needed to flush the tube.
- Aseptically prepare the skin overlying the right side of the neck, plucking feathers if necessary. For an esophagostomy tube, the mid-cervical region is prepped. A higher segment of skin, extending from the caudal aspect of the mandible to the mid-cervical region is prepared for pharyngostomy tube placement.
Note: Classically, esophagostomy tubes have been considered far superior to pharyngostomy tubes in small mammals because the latter have been associated laryngeal movement and a delay in spontaneous feeding, however pharyngostomy tubes are still a potential option in select cases (Huynh et al 2014, Abdelfatah et al 2012, Jones and Bodenham 2005).
- Gently insert a curved hemostat into the oropharynx along the right side of the neck.
- Select an avascular region overlying the jaws of the hemostat and make a small incision through the skin and esophageal wall using the scalpel blade or scissors.
- Grasp the distal tip of the feeding tube with the hemostats.
- Pull the feeding tube through the incision and into the esophagus. There are two possible methods for passing the tube:
- Retrograde: Direct the tip of the tube up and out of the mouth to confirm placement of the tube into the lumen of the gastrointestinal tract. Then redirect the tube tip caudally. Although this technique can be relatively challenging in some mammals—due to a narrow pharynx—and the tube can become trapped around the endotracheal tube, such complications are rare in birds due to their relatively wide oropharynx.
- Normograde: Directly feed the tip of the tube into the distal esophagus or proventriculus. This technique has the advantage of being quicker and easier, however this method does not serve to confirm tube placement within the esophagus.
- Guide the tube down through the crop and into the distal esophagus or proventriculus. Some manipulation is often necessary to pass the tube from the distal crop into the thoracic esophagus (Huynh et al 2014, Harris 2001). If deliberately entering the proventriculus, pass the tube until resistance is felt, then withdraw slightly. In small animals, placement of the tube end in the distal third of the esophagus prevents irritation and minimizes gastric reflux. Tube placement within the gastroesophageal junction can stimulate vomiting (Huynh et al 2014, Devitt and Seim 1997).
- Mark the tube with indelible ink where it exits the body so that migration can be detected (Eirmann and Michel 2015).
- Perform at least a lateral survey radiograph to confirm tube placement (Eirmann and Michel 2015).
- Fasten the tube in place with tape butterflied to the catheter. The tape is then secured using acrylic glue or suture. The tube can be secured to the skin with a Chinese finger-trap suture. Alternatively, a purse-string suture pattern can be placed. An additional suture can be used to attach the tube to the bird’s back (Fig 4) (Huynh et al 2014).
- The incision site generally does not require suturing unless it is unusually large.
- Although it is not strictly necessary to wrap the neck, bandaging can reduce the risk of premature tube removal by the patient. Bandaging also helps to direct the external portion of the tube dorsally to prevent patient chewing or manipulation (Bowles et al 2006). An Elizabethan collar may also be necessary in the select patient.
- Instill warm water into the tube to ensure patency.
- Cap the tube with a male adapter plug between feedings (Fig 5).
Selection of a more distal insertion site, closer to the thoracic inlet, is often needed in long-necked birds. A technique recently described in condors consisted of first performing an ingluviotomy before esophagostomy tube placement because the standard-length feeding tube did not reach the distal esophagus or proventriculus in these birds (Aguilar et al 2012).
Feeding via esophagostomy tube
First, flush the tube with warm water. If medication must be administered, infuse these agents after flushing but before feeding. Slowly infuse warm food, then flush the tube with water again after feeding. Although crop (and stomach) volume is estimated as 3-5% body weight, the proventriculus is much less distensible when compared to the crop and conservative amounts should be fed initially (Fig 6). Huynh et al have recommended starting with 1% body weight or 10 ml/kg per meal. It is particularly important to keep track of the volume infused, including flushes, in very small patients to minimize the risk of patient aspiration.
Although esophagostomy tubes are frequently used in outpatients in other taxa, avian patients are generally maintained in a hospital setting. As treatment progresses and clinical status improves, birds are offered solid food items. Be sure to offer birds of prey cast-free food items (free of skin, feathers, large bone) to prevent egestion and potential tube displacement (Huynh et al 2014).
Monitor the patient closely. Regularly evaluate body weight, body condition, hydration status, as well as the tube site at least once or twice daily. Nutritional assessment should occur at least once daily and feeding orders must be reviewed carefully (Eirmann and Michel 2015). Monitor pertinent laboratory values such as total protein, uric acid, and electrolytes as needed.
Esophagostomy tubes can be used for fairly long periods and have been reportedly left in avian patients as long as 7 weeks without complication (Harris 2001). One advantage of this route, however, is the tube can be removed at any time (Eirmann and Michel 2015). Tube removal is generally based on the presence of clinical improvement, including voluntary eating, paired with a surgical insertion site that has started to retract. The average duration of tube placement was 6.1 + 3.7 days in one survey of 18 raptors (Huynh et al 2014). In two condors with lead poisoning, tubes were tolerated up to 15 and 17 days (Aguilar et al 2012).
To remove an esophagostomy tube, cut the stay sutures, gently extract the tube, and allow the opening to heal by second intention. The incision site will seal in 1 to 2 days, and it usually heals within one week.
Esophagostomy tube placement can serve as a reliable technique for nutritional support of the avian patient. Esophagostomy tubes are generally well tolerated and can reduce patient stress while improving delivery of medications and nutrition.