A nasogastric tube, also known as an NG tube, is a flexible plastic tube that is passed through the nose, down the esophagus, and into the stomach. It can be used for a variety of purposes, including draining the contents of the stomach.
What is a nasogastric tube?
A nasogastric tube is a long, thin, flexible tube that is inserted through the nose, passes down the esophagus, and ends in the stomach. The tube is usually made of polyurethane or silicone. It typically has multiple small openings at the end in the stomach to allow drainage or feeding.
There are a few different types of nasogastric tubes:
- Levin tube – used for stomach drainage
- Salem Sump tube – used for stomach drainage and decompression
- Dobhoff tube – used for feeding
Nasogastric tubes serve a variety of purposes, including:
- Removing contents from the stomach, such as drainage of gastric secretions or blood
- Decompressing the stomach in cases of gastrointestinal obstruction or ileus
- Delivering nutrition into the gastrointestinal tract
- Administering drugs and medications
What does “on free drainage” mean?
“On free drainage” refers to allowing the nasogastric tube to drain the contents of the stomach freely and continuously. This is done by keeping the tube open to the drainage bag below the level of the stomach and allowing gastric secretions to empty out of the stomach by gravity alone.
The nasogastric tube is connected to a drainage bag or container to collect the drainage. The bag needs to be kept lower than the level of the stomach so that the contents can drain out easily. The tube is not clamped, so the stomach contents are able to drain continuously.
Why is a nasogastric tube put on free drainage?
There are several reasons a nasogastric tube may be put on free drainage:
- Gastric decompression – To decompress a distended or obstructed stomach and relieve pressure
- Gastric lavage – To wash out the stomach as a treatment for certain ingested poisons or drugs
- Pre-operative preparation – To empty the stomach before surgery
- Gastrointestinal bleeding – To monitor bleeding and prevent further bleeding by emptying the stomach
- Intestinal obstruction – To decompress the stomach and rest the bowel
- Pancreatitis – To prevent vomiting and reduce pancreas secretion
- Ileus – To relieve edema and distension
Free drainage allows continuous emptying of stomach contents without buildup of pressure in situations where this is beneficial.
What comes out through the tube on free drainage?
The contents that can drain from the stomach through a nasogastric tube on free drainage include:
- Gastric secretions – Acid, enzymes, mucus
- Bile – From duodenum reflux
- Blood – From gastrointestinal bleeding
- Food particles/nutritional supplements – If recently consumed
- Medications – Liquid medications administered directly into stomach
The drainage is typically greenish-brown in color and very watery in consistency. Food contents may be present if the patient has recently eaten. It can be copious in amount, hence the need for continuous drainage. The contents may be tested if clinically indicated.
What color drainage is expected?
The expected drainage color with a nasogastric tube on free drainage is:
- Greenish-brown – This indicates a normal drainage consisting of gastric secretions, bile, and intestinal contents.
- Yellow – May indicate bile drainage due to duodenal reflux into the stomach.
- Red/blood-tinged – Suggests active upper GI bleeding.
- Brown – Coffee ground material may indicate old blood.
- Milky white – Often formula or nutritional supplements if being administered.
- Clear/light yellow – Gastric secretions.
Any major deviation from greenish-brown drainage or a significant change in color may need further assessment. Unusual colors may reflect problems like active bleeding or intestinal obstruction.
How much drainage is normal?
The amount of expected drainage from a nasogastric tube on free drainage can vary significantly depending on the clinical situation. Normal or average drainage amounts may be:
- Gastric decompression: 100-400 mL per hour initially, decreasing over time.
- Gastrointestinal bleeding: Up to 2000 mL in first 24 hours, decreasing daily.
- Bowel obstruction: 500-1200 mL per day.
- Pancreatitis: 100-300 mL per hour initially.
- Ileus: 200-400 mL per day.
Usually, a high initial drainage rate is expected that gradually decreases over time. If the drainage remains very high or increases despite treatment, it may indicate a complication.
What are some possible complications with free drainage?
Some potential complications that can occur with a nasogastric tube on free drainage include:
- Diarrhea – Excessive loss of fluids and electrolytes
- Dehydration – Due to fluid loss from drainage
- Electrolyte imbalances – Particularly sodium, potassium, magnesium
- Stomach ulceration – From prolonged contact with tube
- Aspiration pneumonia – From reflux of drainage into lungs
- Tube blockage – Due to thick drainage or kinking
- Nasal/esophageal erosion – From the tube rubbing
Patients require close monitoring of fluid status, electrolytes, nutrition, and potential respiratory issues. Proper tube placement must be verified intermittently.
What nursing care is required with free drainage?
Nurses need to provide comprehensive care for patients with a nasogastric tube on free drainage, including:
- Frequent monitoring of drainage amount, color, consistency
- Measure and record drainage on an intake/output sheet
- Monitor patient’s vital signs for fluid imbalance
- Monitor electrolytes and nutrition status
- Provide adequate hydration and nutritional support
- Assess patient comfort and need for suctioning
- Keep drainage bag below level of stomach
- Empty drainage bag regularly to prevent pulling
- Monitor and reposition tube as needed
The nurse should also educate the patient on proper nasogastric tube care when they are discharged home with ongoing drainage needs.
When should free drainage be discontinued?
Free drainage should be discontinued when:
- The underlying condition improves and drainage is no longer indicated – for example, with resolution of an ileus or bowel obstruction.
- The patient develops complications from excessive drainage – like severe dehydration or electrolyte imbalance.
- The drainage becomes excessive with concerning color – suggesting major bleeding.
- The patient has persistent respiratory symptoms – raising concern for aspiration.
- The patient needs to start tolerating feeds orally.
- The tube becomes displaced or clogged.
The physician will make the decision to discontinue free drainage based on the patient’s clinical status, drainage amounts, and related tests.
In summary, a nasogastric tube put on free drainage means allowing continuous gravity drainage of stomach contents into a collection bag without clamping the tube. This is done for gastrointestinal decompression, bleeding, decompression, ileus, or other indications requiring emptying of the stomach. The drainage is typically greenish-brown fluid, with the amount varying based on clinical context. Careful nursing care is required to monitor drainage, maintain hydration, prevent complications, and determine when free drainage is no longer needed.