Page 560 - Clinical Small Animal Internal Medicine

528 Section 6 Gastrointestinal Disease

conditions. Placement of these devices is relatively compression and the gastric wall transilluminated to
VetBooks.ir simple, but care must be taken to minimize the risk of ensure that there are no major structures (particularly the
spleen) present between the gastric and abdominal walls.
complications.
The description given below assumes that a manufac-
Indications and Patient Choice tured PEG tube kit is being used, which are provided
Percutaneous endoscopic gastrostomy tube placement with the tube mechanically bonded to a loop of wire at
should be considered in patients with significant dyspha- the proximal end, and a guide wire that features a loop at
gia, anorexia, esophageal or oral pathology with an antic- the distal end. Techniques for the assembly of PEG tubes
ipated need for nutritional support beyond 3–5 days. using sterile pipette tips and standard suture materials
PEG tubes may be placed in both canine and feline have been described, but with the ready availability of
patients, but are of particular use in dogs (particularly commercial PEG kits in the veterinary market, the man-
larger breeds) where the placement of esophagostomy ufacture of tubes from a miscellany of materials is no
tubes is more difficult due to the anatomy of the neck longer recommended.
and cervical esophagus. PEG tubes have the advantage of Once the point of insertion is established, the sterile‐
larger lumens than are typically used in nasoesophageal gloved assistant passes a large hypodermic needle (typi-
or esophageal feeding, and are generally well tolerated cally 18–16 ga, 2+ inches) through the skin and gastric
such that they can be maintained for weeks to months. wall, typically placed just ventral and slightly caudal to
After formation of a stable adhesion of the gastric wall to rib 13. The endoscope operator monitors the hypoder-
the peritoneum and abdominal wall (generally after mic needle entry. Once the hypodermic needle is placed,
10–14 days), it is feasible to convert PEG tubes to lower a guide wire with a terminal loop is threaded through the
profile gastrostomy tubes that are somewhat easier for lumen of the needle by the assistant, and captured by the
clients to maintain and do not feature extraabdominal endoscopist using either flexible alligator or cup biopsy
tubing that must be restrained and maintained. forceps. Once the guide wire loop is captured, it is care-
Placement of PEG tubes is straightforward in most fully pulled through the stomach, esophagus, and oral
patients. Difficulty can be encountered in patients with cavity by withdrawing the endoscope. The assistant
megaesophagus, due primarily to negotiating the lower should feed the guide wire via the needle, while monitor-
esophageal sphincter in these patients. Large, deep‐ ing closely to ensure that the full length of the guide wire
chested dogs can also be more difficult as the normal is not pulled into the stomach lumen.
gastric position in these patients is high under the tho- After the loop of guide wire is withdrawn via the
racic cage, these patients can require substantial insuffla- mouth, it is attached to the proximal end of the tube by
tion of the stomach to allow access, and the resulting passing the tube mushroom tip through the guide wire
ostium and adhesions are under tension after the stom- loop, then through the tube’s own bonded wire loop,
ach is deflated. Larger breed, debilitated dogs have a resulting in the tube proximal end being attached to the
greater risk of tube failure and peritonitis so in these guide wire via linked loops.
patients it may be more prudent to place gastrostomy The guide wire and linked tube, bonded tip first, are
tubes surgically. withdrawn into the oral cavity, through the esophagus
While the procedure is relatively easy to describe, and and into the stomach lumen by the sterile‐gloved assis-
manufactured kits designed to make tube insertion sim- tant. As the guide wire and linked proximal tube end
ple are available, it is still prudent to have at least some encounter the gastric wall, the wall is pulled up against
guidance from an experienced endoscopist when first the flank. The bonded sharp tip of the tube is drawn
learning to place these tubes. through the abdominal wall by continuous gentle trac-
tion. A small stab incision will usually be necessary at the
General Procedure point of tube exit.
Percutaneous endoscopic gastrostomy tubes are placed As the tube is withdrawn through the abdominal wall,
exiting the flank on the left side, so the patient should be the endoscopist replaces the endoscope into the gastric
placed in right lateral recumbence. The left paracostal lumen and monitors the positioning of the distal mush-
region is clipped and surgically prepared. The endoscope room tip against the gastric wall. The mushroom tip
is passed into the stomach, and air insufflated to distend should be placed with sufficient tension to hold the gas-
the stomach against the abdominal wall. While the endo- tric wall against the abdominal wall, but excessive ten-
scope operator is visualizing the gastric wall, an assistant sion should be avoided as this may lead to gastric wall
wearing sterile gloves palpates and presses on the region necrosis below the mushroom tip and failure of the gas-
of maximum distension, to allow the endoscopist to trostomy site. The mushroom tip should gently flatten
establish where the tube will eventually be placed. The the gastric mucosa, but blanching of the mucosa should
endoscope is then manipulated to the point of not be visible on examination. If the mucosa is blanched,