Percutaneous endoscopic gastrostomy (PEG).
Percutaneous endoscopic gastrostomy provides a safe, effective, non-surgical route to establish long-term enteral nutrition.
Nasogastric tube vs. percutaneous endoscopic gastrostomy
The most common method of enteral nutrition is the placement of a nasogastric tube. Although effective, this method poses many difficulties and complications when applied clinically. Because these tubes are thick and made of hard rubber or plastic, they cause a lot of discomfort to the patient, often blocking the lumen and forcing constant tube changes, and the tubes are often displaced. The wall of the tube irritates the esophageal mucosa for a long time, and esophagitis can easily occur, and gastroesophageal reflux often occurs because the nutritional tube destroys the normal cardia function. Frequent reflux can lead to aspiration pneumonia. Long-term use of the nasogastric tube is also prone to parotitis and destruction of nasal cartilage. The percutaneous endoscopic gastrostomy (PEG) has been in clinical use since 1980, providing a safe, effective, non-surgical way to establish long-term enteral nutrition access, and is now widely used in clinical practice. The technique is performed on approximately 200,000 patients each year in the United States. The drag-out technique was first utilized by Pon-sky and Gauderer, and although there have been a number of improvements based on this technique, the drag-out method remains the most commonly used method.
Preoperative preparation
Proper preoperative preparation helps to reduce the incidence of complications. Patients should fast for 8 hours before surgery and be routinely given antibiotics against G+ bacteria, cefazolin is well known to kill these and other common organisms. The patient should be placed in a supine position with the head elevated to minimize aspiration, and because this position does not allow easy insertion of the gastroscope into the esophagus, the patient is usually placed in a left lateral position initially and then returned to a supine position. The suction device should aspirate the secretions from the oropharynx in a timely manner and ensure that the patient maintains an adequate oxygen supply.
Pull out technique
After the patient is positioned, oral lidocaine syrup or intravenous sedation is administered, and the abdominal puncture site is cleaned and disinfected. The chamber brightness is reduced after insertion of the gastroscope. When the translucent point of the gastroscope is seen from the abdominal wall, it indicates that the tissue between the stomach and the abdominal wall has been pushed away and the stomach wall is in direct contact with the abdominal wall.
The gastrostomy puncture site should be chosen where the transillumination point of the gastroscope is brightest, usually in the left upper abdomen. The finger pressure on the abdominal wall puncture site is visible through the gastroscope as an acupressure mark on the gastric wall. After the optimal puncture site is selected, local infiltration anesthesia is applied and the needle is withdrawn while the needle is being inserted. When air is withdrawn, the tip of the needle should be visible in the stomach at the same time.
After injection of local anesthetic at the puncture site, an incision of approximately 1 cm is made in the local skin, and a trocar needle is inserted into the gastric cavity. A long wire is then inserted from the trocar into the gastric lumen, and when the wire enters the stomach, it is clamped with a biopsy forceps under the gastroscope and then led out of the mouth as the gastroscope is withdrawn. The end wire of the PEG tube is snapped onto the wire outside the oral cavity, and then the wire is tightened from the abdominal wall puncture site to lead the PEG tube from the esophagus to the stomach and dragged out of the body from the puncture site. At this point, the gastroscope is reinserted and the position of the PEG tube head is checked, noting any excessive tension on the gasket inside the catheter head. When the examination is complete, the gastroscope is withdrawn and the PEG tube is secured by attaching a tab to the root of the PEG tube outside the abdominal wall, thus maintaining close contact between the stomach wall and the abdominal wall.
PEG was originally designed to provide a long-term enteral nutrition route for patients who have normal gastrointestinal function but are unable to consume food orally. All patients who are expected to be unable to consume nutrients for more than 2 weeks or more should be on nutritional support. If the patient has normal gastrointestinal function and the expected duration of enteral nutrition support does not exceed 30 days, a nasogastric or nasoenteric tube can be placed for nutritional support. If the expected duration of enteral nutrition is >30 days, a gastrostomy should be considered. These patients may have severe neurological or developmental dysphagia, traumatic or neoplastic obstruction of the oropharynx, or those who are critically ill and require prolonged tracheal intubation.
PEG has been used in a growing population of patients with burns (even through the skin of the burn site) to facilitate the implementation of enteral hyperthermia nutritional support. It has also been used in patients with esophageal, head and neck cancers receiving adjuvant therapy. Patients with severe maxillofacial trauma can also benefit from PEG.
Non-nutritional applications of PEGs include gastrointestinal decompression for impaired gastric emptying, inoperable intestinal obstruction; pediatric drug administration and biliary fistulas; external drainage of bile back into the patient; and simultaneous placement of multiple PEGs as a method of gastric immobilization in patients with esophageal hiatal hernia and gastric torsion.
Contraindications to PEG are divided into three categories: absolute, relative and potential contraindications.
Absolute contraindications include coagulation disorders, peritonitis, peritoneal dialysis, varices in the gastric wall, absence of the stomach, and any condition that precludes gastroscopy.
Relative contraindications include those conditions that were previously considered absolute contraindications but can be treated with ultrasound imaging, good preoperative preparation, and aggressive treatment for PEG.
The following conditions are not contraindications to PEG, but must be performed with caution as complications are likely to occur.
These include: postoperative, dilated small bowel collaterals, ventriculoperitoneal shunts, and severe cardiac disease. Postoperative abdominal surgery is not contraindicated if precise manipulation and visualization of the transillumination point is possible, but a safe puncture site must be found for such patients.
Good skin care after gastrostomy is very important.
A discharge or granulation around the canal opening due to rejection is often seen. This is easily treated by scrubbing off the discharge with hydrogen peroxide and exposing the area. The granulation tissue can be cauterized with silver nitrate solution. Avoid using impermeable dressings as they can easily damage the underlying skin.
Once the PEG tube has been safely placed, the next question is how to administer feedings through it. Interstitial feeding is preferred because it is easier to perform (no pump required), well tolerated, and physiologically appropriate. The choice of formula should be specific to the patient’s energy requirements, tolerance level and systemic disease status. Gastric residual volume should be routinely measured until fully tolerated, and intolerance should be considered if found to be greater than 100 ml.
PEG tubes should be replaced when worn, obstructed and fistulas occur.
When a PEG tube is removed prematurely and recklessly, peritonitis is likely to occur and must be detected promptly and treated with negative pressure nasogastric drainage, intravenous rehydration and antibiotics. If the patient shows signs of peritonitis or bacteraemia, an emergency caesarean section should be performed at this time.
Some PEG tubes need to be removed or replaced endoscopically. Nowadays, they are designed to be more practical and can be removed directly from outside the body without endoscopic removal. Gauderer et al. invented a low-profile gastrostomy tube with a skin fixation device with an anti-reflux flap that allows for nutrient infusion close to the skin stoma. The device can be placed after the removal of a previously placed gastrostomy tube or directly during the establishment of a PEG channel. For patients requiring monitoring, it is preferable to place a standard nutrition tube in the device to make it easier for nursing staff to handle.