Enteral Access Procedures

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CHAPTER 10 Enteral Access Procedures

Benjamin Herdrich, Jon B. Morris

Case Study

A 63-year-old male with an extensive smoking history presents to his physician complaining of 2 months of increasing hoarseness and difficulty swallowing. Workup, including laryngoscopy, reveals a large pharyngeal tumor. Plans are made for radical surgical resection, including partial pharyngectomy. The patient is referred to a general surgeon for placement of a feeding tube at the time of his operation in anticipation of postoperative difficulty tolerating oral intake.

BACKGROUND

Nutritional support is an essential component of the treatment of critically and chronically ill patients. Patients who cannot meet their own nutritional needs through oral intake can be supported with parenteral (intravenous) or enteral (gastrointestinal tract) feeding. Parenteral feeding is an effective means of providing nutritional support to those patients who cannot be fed enterally and provides lifesaving therapy for patients with limited gastrointestinal tract absorptive capacity. The shortcomings of parenteral nutrition, however, have become increasingly evident as experience with this approach has grown; these include high rates of catheter-related, infectious, and metabolic complications as well as liver dysfunction. In contrast, enteral feeding is associated with fewer complications, is less expensive, and is not dependent on central venous access.

A number of options for enteral access exist; each has unique advantages and disadvantages. These include nasoenteric tubes, gastrostomy tubes, and jejunostomy tubes. Nasoenteric tubes, which include large-bore nasogastric tubes and small-bore nasoenteric tubes, can be placed at the bedside without the need for surgery and provide safe, short-term enteral access. Nasoenteric tubes are associated with several complications, including errors in tube placement (e.g., intracranial or intrabronchial intubations), sinusitis, nasal synechiae, and nasal alar necrosis. Surgically placed gastrostomy tubes (G-tubes) provide more durable, long-term enteral access and can be used for feeding or gastric decompression. In appropriate patients, they may be placed percutaneously with endoscopic assistance, obviating the need for larger open incisions. Jejunostomy tubes (J-tubes) are indicated in patients with contraindications to gastrostomy tube placement (e.g., patients undergoing a transhiatal esophagectomy) and patients with severe reflux or delayed gastric emptying. A variety of laparoscopic approaches to tube gastrostomy and jejunsotomy are in use, increasing the options further. This chapter focuses on the most common enteral access procedures: percutaneous endoscopic gastrostomy (PEG) tube placement and open approaches to tube gastrostomy and tube jejunostomy.

CORRECT PLACEMENT OF NASOENTERIC TUBES SHOULD BE CONFIRMED RADIOGRAPHICALLY BEFORE THE INITIATION OF ENTERIC FEEDING.

INDICATIONS FOR SURGERY

I. Nutritional Support: Enteral access is required when patients’ oral intake is insufficient to meet their nutritional needs. Nutritional support should be considered if: (1) a patient has been without nutrition for 5 to 7 days; (2) the duration of the condition is expected to exceed 10 days; or (3) the patient is malnourished. Enteral nutritional support is only feasible in patients with sufficient small bowel absorptive capacity. Patients who do not meet this requirement (e.g., patients with short gut syndrome) require parenteral nutrition.
II. Prophylactic Enteral Access: Patients with upper-airway or foregut cancers who undergo extensive surgical resection and adjuvant radiation and chemotherapy often have difficulty maintaining adequate caloric intake during the treatment period. In anticipation of this, many of these patients undergo either gastrostomy or jejunostomy placement at the time of surgical resection.
III. Decompression: Patients who cannot tolerate gastric feeding because of severe reflux, gastric atony, or inoperable bowel obstruction (e.g., patients with metastatic cancer) may benefit from G-tube placement for gastric decompression.

PREOPERATIVE EVALUATION

I. History: The preoperative history should allow for a determination of the amount of time enteral access will be needed and whether gastric or jejunal feeding is preferable. A history of feeding intolerance should be elicited in patients already being fed through a nasoenteric tube; patients who are not tolerating gastric feeding through a nasogastric tube may be better served by a J-tube (Fig. 10-1).
II. Laboratory Testing: Laboratory testing should include a complete blood count, electrolytes, and coagulation studies. Thrombocytopenia and coagulopathies should be corrected before enteral access procedures.
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Figure 10-1 Preoperative evaluation for enteral access.

COMPONENTS OF THE PROCEDURE AND APPLIED ANATOMY

Preoperative Considerations

I. Prophylactic antibiotics to cover gram-positive organisms should be given within 1 hour before the procedure.
II. G-tubes and J-tubes are placed under general anesthesia. PEG tubes can be placed with intravenous sedation and local anesthetics.

Positioning and Preparation

I. The patient is placed in the supine position with the arms extended. The head of the bed is elevated.
II. The surgical preparation should extend to the nipples superiorly, the pubic symphysis inferiorly, and the midaxillary lines laterally.

PEG Tube

I. Placement of a PEG tube is best accomplished by two surgeons, one operating the endoscope and the other positioned next to the patient’s abdomen.
II. Passing the Endoscope

A. The endoscope is lubricated and passed through the pharynx and esophagus, into the stomach.
B. The stomach is insufflated with air.

III. Choosing the Gastrostomy Site

A. The ideal site for gastrostomy placement is identified by palpation, transillumination, and needle aspiration. The site is typically two fingerbreadths below the costal margin, just to the left of the midline.
B. Potential sites for tube insertion are palpated with a single finger. The impression of the finger on the stomach wall is noted by the endoscopist. Inability to appreciate this impression suggests interposition of other organs, such as the colon or liver, between the stomach and the abdominal wall (Fig. 10-2).
C. Once an appropriate site is identified using palpation, the room lights are dimmed. Transillumination of the abdominal wall with endoscopic light can be appreciated in most patients unless colon or liver is interposed between the stomach and the abdominal wall.
D. The presence of bowel interposed between the abdominal wall and the stomach can also be excluded by inserting a 21-gauge needle attached to a syringe partially filled with saline at the site while aspirating. If bubbles are noted in the syringe before the needle is seen entering the stomach by the endoscopist, a different site should be identified.
E. If a safe site cannot be identified, tube gastrostomy should be performed through an open incision.

image

Figure 10-2 During PEG tube placement, the proposed gastrostomy site is palpated. The impression of the finger on the stomach wall is noted by the endoscopist.

(From Yeo C: Shackelford’s Surgery of the Alimentary Tract, 6th ed. Philadelphia, Saunders, 2007.)

PALPATION, TRANSILLUMINATION, AND NEEDLE ASPIRATION AT THE PROPOSED INSERTION SITE MINIMIZE THE RISK OF LIVER OR COLON INJURY.

IV. Accessing the Stomach

A. A 14-gauge angiocatheter is inserted into the stomach under endoscopic visualization.
B. A wire is passed through the catheter into the stomach.
C. A snare is threaded through the endoscope and used to grasp the wire.
D. The endoscope is withdrawn with the snare and wire, and one end of the wire is pulled out of the patient’s mouth.

V. Tube Placement

A. The distal end of the PEG tube is attached to the end of the wire that has been pulled through the patient’s mouth.
B. The proximal end of the PEG tube (the bumper) is grasped with the endoscopist’s snare (still threaded through the endoscope).
C. The wire is withdrawn through the abdominal wall, thus pulling the PEG tube through the esophagus, into the stomach, and out the anterior abdominal wall. The endoscopist follows the tube into the stomach.
D. The endoscopist opens the snare when the bumper is in place, within the stomach, and the gastrostomy site is inspected to ensure hemostasis.
E. A self-retaining bar is threaded over the distal end of the PEG tube to secure it at the skin. Care is taken not to advance the bar too far; by applying gentle traction on the PEG tube, the physician should easily be able to lift the bar 1 cm off the skin and rotate it 360 degrees (Fig. 10-3).

image image

Figure 10-3 A, The gastrostomy tube is pulled through the mouth and esophagus, into the stomach, and out the abdominal wall. B, An inner plastic bumper and an outer self-retaining bar are approximated to hold the tube in place.

(From Sabiston DC Jr [ed]: Atlas of General Surgery. Philadelphia, Saunders, 1994.)

STOMACH WALL NECROSIS MAY RESULT IF THE SELF-RETAINING BAR AND BUMPER ARE BROUGHT TOO CLOSE TOGETHER AROUND THE INTERPOSED ABDOMINAL AND STOMACH WALLS.

F. Air is suctioned out of the stomach. The endoscope is removed.

Open Tube Gastrostomy

I. Incision: Open G-tube placement is performed through an upper midline incision, 6 to 8 cm in length. Alternatively, a left paramedian incision can be used.
II. Insertion of the Gastrostomy Tube

A. The stomach is identified and grasped with an instrument.
B. The site for the gastrostomy tube is chosen, typically in the midportion of the stomach, closer to the greater curvature. Two concentric purse-string sutures are placed at the proposed site.
C. A gastrotomy (an opening in the stomach) is made at the center of the purse-string sutures, and the tube is inserted into the stomach (Fig. 10-4).
D. The inner and outer purse-string sutures are tied down, invaginating the stomach wall around the gastrostomy tube.

III. Securing the Stomach to the Anterior Abdominal Wall

A. The distal end of the tube is brought out through a stab incision in the anterior abdominal wall left of the midline.
B. The stomach surrounding the tube is sutured to the anterior abdominal wall around the exit site (Fig. 10-5).

IV. Closure of the Wound

A. The fascia and the skin are closed.
B. The gastrostomy tube is secured to the abdominal wall with either a self-retaining bar or sutures.

image

Figure 10-4 During placement of a gastrostomy tube, two purse-string sutures are placed around the proposed site. The tube is placed through an enterotomy in the center of those sutures.

(From Yeo C: Shackelford’s Surgery of the Alimentary Tract, 6th ed. Philadelphia, Saunders, 2007.)

image

Figure 10-5 A and B, The purse-string sutures are tied down and invaginate the gastric wall around the gastrostomy tube.

(From Yeo C: Shackelford’s Surgery of the Alimentary Tract, 6th ed. Philadelphia, Saunders, 2007.)

Open Tube Jejunostomy

I. Incision: Open J-tube placement is performed through an upper midline incision, 6 to 8 cm in length. Alternatively, a paramedian incision can be used.
II. Insertion of the Jejunostomy Tube

A. The transverse colon is retracted cephalad, and the ligament of Treitz is identified.
B. A site for insertion of the J-tube, typically 30 to 40 cm distal to the ligament, where the mesentery is mobile enough to allow the small bowel to reach the abdominal wall, is identified.
C. A single purse-string suture is placed at the chosen site, and an enterotomy is made in the center of the purse string.
D. The J-tube is inserted through the enterotomy and passed approximately 10 cm distally. The purse string is tied.

III. Creation of a Serosal Tunnel: Beginning at the insertion site and extending proximally, the jejunal serosa is closed over the tube with four to six interrupted sutures (Fig. 10-6).

image

Figure 10-6 Seromuscular sutures create a serosal tunnel for the jejunostomy tube.

(From Sabiston DC Jr [ed]: Atlas of General Surgery. Philadelphia, Saunders, 1994.)

CARE MUST BE TAKEN TO AVOID NARROWING THE LUMEN OF THE JEJUNUM BECAUSE DOING SO MAY CAUSE AN OBSTRUCTION.

IV. Securing the Jejunum to the Anterior Abdominal Wall

A. The end of the tube is brought out through a stab incision to the left of the midline.
B. The jejunum around the J-tube is sutured to the anterior abdominal wall in multiple locations.

V. Wound Closure: The fascia and skin are closed. The J-tube is sutured to the skin.

NEWLY PLACED ENTERAL TUBES SHOULD BE SECURED WITH A BULKY DRESSING TO PREVENT EARLY TUBE DISLODGEMENT.

POSTOPERATIVE COURSE

Benign pneumoperitoneum is common immediately after PEG tube placement and does not require further workup unless the patient has peritonitis or other concerning findings.

During recovery from anesthesia, enteral tubes are attached to drainage bags or capped. The latter approach is often preferable, particularly during patient transport, to avoid early tube dislodgement. Patients requiring immediate enteral nutrition can usually begin enteral feeding on the first postoperative day. G-tube feeding is typically administered in intermittent boluses. Residual gastric volumes should be checked before each bolus. If residual volumes exceed 200 mL, feedings should be held until gastric emptying improves. In contrast, J-tube feeding is usually administered as a continuous infusion. Enteral tubes should be flushed at least once a day or after each feeding to avoid clogging.

MINIMIZE ASPIRATION BY CHECKING RESIDUAL VOLUMES AND ELEVATING THE HEAD OF THE BED BEFORE THE ADMINISTRATION OF FEEDING.

After enteral tube placement, formation of an epithelialized tract requires approximately 6 weeks. Gastrostomy and jejunostomy tubes should not be removed or replaced before this time.

COMPLICATIONS

I. Wound complications are common after enteral tube placement. Even mild drainage of enteral contents around a gastrostomy tube or jejunostomy tube may lead to skin excoriation. Antacid therapy can help to make the draining enteral contents less irritating. However, in severe cases, tube feeds may need to be held or the tube may need to be removed to allow for healing. The pressure exerted by the tube on the abdominal wall can also result in skin ulceration. If severe, the tube may need to be removed to allow for wound healing. It is usually counterproductive to replace the tube with a larger one because this enlarges the defect and causes continued erosion.

UPSIZING A TUBE TO TREAT DRAINAGE IS RARELY EFFECTIVE AND MAY CAUSE ABDOMINAL WALL EROSION.

II. Although rare, fungal and bacterial skin infections sometimes develop around the tube site. Such infections usually respond to topical antifungal agents and systemic antibiotic therapy.
III. Bleeding after PEG tube placement may result from trauma during passage of the tube through the stomach and abdominal wall. Bleeding is usually self-limited and in some cases can be controlled by transiently tightening the self-retaining bar. Pressure should be released once the bleeding has stopped to avoid pressure necrosis of the gastric wall. Rarely, bleeding requires operative exploration.
IV. Mechanical obstruction must be distinguished from postoperative ileus in all patients who cannot tolerate feeding after an enteral access procedure; computed tomography scanning with contrast administered through the tube is frequently a useful study in this regard. Mechanical obstruction can be caused by proximal or distal migration of the tube, volvulus of the jejunum around the point of fixation to the abdominal wall, or adhesions. If the tube has migrated, repositioning it is often sufficient treatment. Other causes of mechanical obstruction typically require reoperation.
V. Injury to other organs, including the liver and bowel, can occur during PEG tube placement. If recognized at the time of the procedure, such injuries are immediately repaired. Unrecognized colonic injuries can result in fistula formation between the stomach and colon and may present with feeding intolerance or diarrhea. If the diagnosis of a gastrocolic fistula is made, operative repair is indicated.
VI. Diarrhea is often associated with enteral feeding. Mild antidiarrheal agents (i.e., bismuth subsalicylate [Kaopectate]) and bulking agents (i.e., psyllium) may provide symptomatic improvement. Decreasing the feeding rate or bolus volume and switching formulations (e.g., isotonic, low-fat, lactose-free) may also help to relieve symptoms if other causes have been ruled out. Antimotility agents can be used only if infection has been ruled out.
VII. Dislodgement of a PEG tube in the postoperative period (i.e., <2 weeks after placement) may result in free spillage of gastric contents into the peritoneal cavity and generally necessitates immediate operative exploration and repair of the gastrotomy. Surgical approaches to tube placement that involve approximation of the bowel or stomach to the anterior abdominal wall safeguard against spillage of enteric contents into the peritoneal cavity. Patients may be observed without immediate intervention in the event that such tubes are dislodged in the early postprocedure period. Tubes dislodged 6 weeks or more after placement can usually be replaced through the tract, which is well epithelialized by this time. Radiographic confirmation of appropriate positioning is recommended before reinitiation of tube feeding.
VIII. Metastases at the abdominal insertion site have been reported after PEG tube placement in patients with cancers of the head, neck, or esophagus.

SUGGESTED READINGS

Gorman R, Nance ML, Morris JB. Enteral feeding techniques [[ed]]. Torosian MH, editor. Nutrition for the Hospitalized Patient: Basic Science and Principles of Practice. CRC Press, New York, 1995, 329-351.

Mullen JL, Morris JB, Yu JC. Enterostomies. In: Daly JM, Cady B, editors. Atlas of Surgical Oncology. Philadelphia: Mosby-Year Book; 1993:19-37.

Tapia J, Murguia R, Garcia G, et al. Jejunostomy: techniques, indications, and complications. World J Surg. 1999;23:596-602.

Weltz CR, Morris JB, Mullen JL. Surgical jejunostomy in aspiration risk patients. Ann Surg. 1992;215:140-145.

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