Tube feeding, formally known as enteral nutrition, is a medical process designed to deliver essential nutrients directly into the digestive system when a person cannot safely or adequately consume food by mouth. This method uses a soft, flexible tube to bypass the oral cavity and esophagus. Tube placement is highly individualized, depending primarily on the patient’s condition and the anticipated duration of nutritional support. The location of the tube tip determines whether the stomach or the small intestine receives the nutrition, a decision based on clinical assessment and the functional status of the patient’s gastrointestinal tract.
Short-Term Access: Tubes Placed Through the Nose or Mouth
For patients expected to need nutritional support for only a few weeks, the feeding tube is typically inserted through the nose or mouth. This approach utilizes the natural pathway of the upper digestive tract, making it a less invasive and temporary solution. The tube is carefully guided through the nasal passage or mouth, down the pharynx, and into the esophagus.
The ultimate destination of the tube tip determines its specific name and function. A nasogastric (NG) tube is the most common type, resting within the stomach. This placement allows for easy administration of nutrition and can also be used to remove air or fluids from the stomach, a process known as decompression.
When the stomach needs to be bypassed, the tube is advanced further into the small intestine, becoming a nasojejunal (NJ) tube, positioned in the jejunum. To reach this point, the tube must pass through the stomach and the pylorus. Another variation is the orogastric (OG) tube, inserted through the mouth instead of the nose, a method often preferred for infants or when nasal passages are compromised.
Long-Term Access: Tubes Placed Directly Through the Skin
When nutritional support is required for more than four to six weeks, a permanent and comfortable solution is preferred: direct placement through the abdominal wall. These procedures are performed percutaneously (through the skin), often using endoscopic or radiological guidance. This method avoids the irritation and discomfort associated with a tube resting in the nasal or pharyngeal area for an extended time.
The most common long-term device is the gastrostomy tube, often called a G-tube or Percutaneous Endoscopic Gastrostomy (PEG) tube. This tube enters through a small incision in the abdomen directly into the stomach. An internal bumper or balloon holds the tube securely against the inner stomach wall, while an external fixation device secures it on the skin’s surface.
An alternative long-term route is the jejunostomy tube (J-tube), placed directly through the abdominal skin into the jejunum. A frequently used option is the gastrojejunostomy tube (GJ-tube), which is placed into the stomach but features a thinner extension threaded into the jejunum. This provides access to both the stomach and the small intestine, allowing for feeding into the jejunum while simultaneously permitting gastric decompression.
Clinical Factors Influencing Tube Placement
The decision regarding tube placement is rooted in several clinical factors. The primary consideration is the anticipated duration of the need for tube feeding. Short-term use (typically less than a month) dictates the use of non-surgical, easily removable nasoenteric or oroenteric tubes.
A significant factor is the risk of pulmonary aspiration, which occurs when stomach contents are inhaled into the lungs. Patients with impaired consciousness, poor gag reflex, or mechanical ventilation are at a higher risk. In these cases, a post-pyloric feeding site, such as the duodenum or jejunum, is often selected to bypass the stomach and reduce the risk of reflux and aspiration.
Issues with gastric motility also influence the site choice. Conditions like gastroparesis or critical illness can cause delayed gastric emptying, meaning the stomach cannot effectively move food forward. When the stomach cannot tolerate the feeding formula, the accumulated volume can lead to vomiting or reflux. Bypassing the stomach entirely with an NJ-tube or J-tube ensures nutrition is delivered directly to the small intestine, which is typically still functional and capable of nutrient absorption.