A gastrostomy is a surgical procedure in which an opening is cre-ated into the stomach for the purpose of administering foods and fluids. In some instances, a gastrostomy is preferred for prolonged nutrition (greater then 3 to 4 weeks)—for example, in the elderly or debilitated patient. Gastrostomy is also preferred over NG feedings in the comatose patient because the gastroesophageal sphincter remains intact. Regurgitation and aspiration are less likely to occur with a gastrostomy than with NG feedings.
Different types of feeding gastrostomies may be used, includ-ing the Stamm (temporary and permanent), Janeway (perma-nent), and percutaneous endoscopic gastrostomy (temporary) systems. The Stamm and Janeway gastrostomies require either an upper abdominal midline incision or a left upper quadrant trans-verse incision. The Stamm procedure requires the use of concen-tric purse-string sutures to secure the tube to the anterior gastric wall. To create the gastrostomy, an exit wound is created in the left upper abdomen. The Janeway procedure necessitates the cre-ation of a tunnel (called a gastric tube) that is brought out through the abdomen to form a permanent stoma.
A percutaneous endoscopic gastrostomy (PEG) is a proce-dure that requires the services of two physicians (or a physician and a nurse with specialty skills). After administering a local anes-thetic, one physician inserts a cannula into the stomach through an abdominal incision and then threads a nonabsorbable suture through the cannula; the second physician looks through an en-doscope that has been passed into the upper GI tract and uses the endoscopic snare to grasp the end of the suture and guide it up through the patient’s mouth. The suture is knotted to the dilator tip at the end of the PEG tube. The endoscopist then advances the dilator tip through the patient’s mouth while the first physi-cian pulls the suture through the cannula site. The attached PEG tube is guided down the esophagus, into the stomach, and out through the abdominal incision (Fig. 36-8A). The mushroom catheter tip and internal crossbar secure the tube against the stomach wall. An external crossbar or bumper keeps the catheter in place.
A tubing adaptor is in place between feedings, and a clamp or plug is used to close or open the tubing. If an endoscope is unable to pass through the esophagus, then the gastrostomy can be performed under x-ray guidance through the abdominal wall. This procedure is known as fluoroscopically guided percutaneous gastrostomy, or FGPG ( Johnson, 1997).
The initial PEG device can be removed and replaced once the tract is well established (10 to 14 days after insertion). Re-placement of the PEG device is indicated to provide long-term nutritional support, to replace a clotted or migrated tube, or to enhance patient comfort. The PEG replacement device should be fitted securely to the stoma to prevent leakage of gastric acid and is maintained in place through traction between the internal and anchoring devices.
An alternative to the PEG device is a low-profile gastrostomydevice (LPGD) (see Fig. 36-8B). The LPGD may be inserted3 to 6 months after initial gastrostomy tube placement. These de-vices are inserted flush with the skin; they eliminate the possibil-ity of tube migration and obstruction and have antireflux valves to prevent gastric reflux. Two types of devices may be used— obturated or nonobturated. The obturated devices (G-button) have a dome tip that acts as an internal stabilizer. A major draw-back is the need for a physician to obturate (insert a tube that is larger than the actual stoma). The nonobturated device (MIC-KEY) has an external skin disk and is inserted into the stoma without force; a balloon is inflated to secure placement. A nurse in the home setting can insert these devices easily. The drawbacks of both types of LPGDs are the inability to check residual volumes (one-way valve) and the need for a special adap-tor to connect the device to the feeding container.
Patients with severe gastroesophageal reflux are at risk for as-piration pneumonia and therefore are not candidates for a gas-trostomy. A jejunostomy is preferred, or jejunal feeding through a nasojejunal tube may be recommended.