A gastrostomy tube (G-tube) is indicated in patients with a need for long-term pre-pyloric feeding. Endoscopic gastrostomy tube placement is now the preferred modality over surgical gastrostomy owing to a less invasive nature and faster time to start feeding. During endoscopic gastrostomy tube placement, a small incision is made over anterior abdominal wall through which tube is placed via push method (the tube inserted percutaneously through the incision) or pull technique (the tube is pulled out from the stomach through the incision). Once the tube is placed, the percutaneous tract starts maturing in about 1 to 2 weeks and usually well formed in 4 to 6 weeks. However, in certain conditions such as severe malnutrition, immunocompromised patients, and large ascites, tract maturity is further delayed. If a PEG tube is dislodged within a month after placement, then endoscopic replacement is recommended. However, if the tube is dislodged after 4 to 6 weeks when tract maturity is expected, bedside replacement is usually sufficient. If the tube is dislodged within 4 weeks of initial placement, patients are at significant risk of peritonitis and perforation due to peritoneal spillage of gastric contents through the immature track, and replacement should not be attempted without surgical consultation. Blind attempt to re-insert the tube or even foley placement in an immature tract can lead to inadvertent placement of the tube into the peritoneal cavity. If the tube needs to be replaced after the track is expected to be matured, will be discussed here in this topic.
During endoscopic placement of G-tube placement, a gastroscope is inserted, and air insufflation inflates the stomach. About 2.5 cm below the costal margin and medial to xiphoid process, an area of maximal transillumination is identified while shining an endoscope light through the anterior gastric wall transillumination. A good 1:1 contact is confirmed by firmly applying pressure on this point and visualizing stomach wall sliding off by this pressure at the same time. Once the site is confirmed, this area is marked with a surgical pen for incision site. After the tube placement with an endoscope, the mechanism of track maturation include anterior gastric wall adhering to the abdominal wall forming a gastrocutaneous fistula.
The indications of percutaneous endoscopic gastrostomy (PEG) tube replacement are:
Bedside/bling PEG tube replacement is contraindicated in following situations:
For bedside replacement of G-tube:
First, if the tube is still in place, it should be examined. There are cases of a malfunctioning tube. It is vital that the clinician take a careful history and review prior records when they are available, to know the type of tube (with internal mushroom cap versus internal balloon). The dressing is removed, and percutaneous incision site is examined for any signs of infection, track closure, or tube displacement in subcutaneous tissue. The area should be appropriately cleaned with sterilizing alcohol or povidone iodine. The area is covered with either sheath in PEG replacement kit or surgical drapes to avoid contaminating the surroundings during PEG replacement.
If PEG tube is not completely dislodged but has been clogged or malfunctioning, the old tube needs to be removed. If the old tube is endoscopically placed tube with internal mushroom tip, then gentle traction is applied to the external portion of the tube to remove internal mushroom. This has to be done with very gentle traction, and excessive force should be avoided at all cost as it can lead to disruption of an even well-formed track. If unusual resistance is felt during attempted removal of the tube by gentle traction, it is best to remove tube after endoscopic cutting of internal bumper/mushroom cap and removal of rest of the tube through external puling. If the old G-tube is with an internal balloon, the balloon is deflated by aspirating fluid through the balloon port which usually consists of 8 to 10 mL of fluid. After this step, once the tube is removed, the similar size PEG tube is prepared to be inserted.
For replacement G-tube, tubes with the balloon tip are usually preferred to minimize the risk of disruption of the old track. A similar diameter PEG tube as the prior tube should be used as a replacement tube. First, the balloon functioning is confirmed outside the body by injecting 8 to 10 mL of saline in balloon port. Once confirmed, the balloon is then deflated again. The balloon tip G-tube is either inserted into track blindly or via the use of guidewire with or without fluoroscopy and is advanced within the track. Once fully inside, the balloon is inflated with 8 to 10 mL of saline or distilled water. The tube is slowly retracted till gentle resistance is encountered due to internal balloon opposing gastric wall. At this point, the external portion of the tube is secured with dressing. Both ports of traditional G-tube (feeding port and meds port) are flushed and then capped. A dressing is then applied based on institutional policy. It is vital to apply protective dressing to avoid accidental pulling or dislodgement in patients with altered mentation.
The final step in PEG tube replacement is to confirm the placement. There are certain ways, gastric placement can be confirmed. The simplest method could be bedside method such as flushing air through the tube and auscultating for gastric gurgle. However, this method is quite unreliable. The most accurate tests are confirming internal balloon placement with an endoscope. However, this might not be cost-effective. The most commonly used technique in most practices is to obtain water-soluble contrast through the replacement tube and obtaining a post, contrast-enhanced, abdominal x-ray to confirm placement in the stomach.
The major complication of PEG tube replacement is the accidental peritoneal placement of the tube. Peritoneal tube placement should be suspected when after tube replacement or after resuming feeding through the tube, the patient starts having abdominal pain, fever, and signs of frank peritonitis on the exam. If this happens, a prompt investigation should be performed using contrast x-ray with water-soluble contrast or with CT scan of the abdomen. Tube feeds should be stopped immediately. Surgical consult should be obtained, and broad-spectrum antibiotics should be initiated as soon as possible. The patient is then managed conservatively with close hemodynamic monitoring along with surgical assistance if needed.
Other complications are rare, but the tube replacement site can get infected especially if the balloon is underinflated or not opposing the gastric wall. This can lead to leakage of gastric contents into the track. Bleeding due to trauma during tube replacement is rare but can happen.
G-tube malfunction is a commonly encountered in clinical practice both in inpatient and outpatient practice. At some institutes, G-tube replacement is exclusively done by either gastroenterology service or interventional radiology service depending on who initially placed the tube. However, if the patient is seen in the clinic, emergency room, or a nursing home for malfunctioning G-tube, an appropriate service, either gastroenterology or interventional radiology, should be consulted. If the tube has dislodged or come out, the gastrocutaneous fistula track will start to close as soon as in 8 hours but definitely in 24 hours. The longer the duration the tube has been out of place, higher the chances that the track has narrowed or closed. If more than 24 hours has elapsed after G-tube has been displaced, a blind forceful attempt to put a Foley or G-tube should not be done, and replacement should be referred to specialized services (gastrointestinal or interventional radiology). If G-tube has been dislodged for less than 24 hours, consider putting a temporary tube such as a Foley catheter (similar size as G-tube) to prevent the closure of the track and contact a specialty service for replacement. Once the tube is replaced, gastric placement confirmation with contrast-enhanced, abdominal x-ray is recommended. If the patient develops any signs of peritonitis after tube replacement, accidental intraperitoneal tube placement should be suspected and further evaluated.