A nasogastric (NG) tube is a thin, flexible tube inserted through the nostril, down the throat, and into the stomach. This device is used when a person experiences a bowel obstruction, a blockage preventing the normal passage of food, fluid, and gas through the intestines. The primary role of the NG tube is to provide relief by addressing the immediate consequences of the blockage. It is a temporary, non-surgical measure used to manage symptoms while the underlying obstruction is addressed.
Why Decompression is Necessary: The Function of the NG Tube
The fundamental goal of placing an NG tube for a bowel obstruction is gastric decompression. When the intestine is blocked, the contents of the stomach and upper small bowel—including digestive fluids, air, and gas—cannot move forward and begin to back up. This buildup causes significant pressure and distention within the stomach and the bowel section just above the obstruction.
The NG tube is attached to suction, creating a direct pathway to remove accumulated fluid and air. By draining the excess contents, the tube effectively reduces pressure inside the digestive system, which rests the bowel. This decompression provides significant symptomatic relief from severe bloating and abdominal pain.
Removing the buildup also prevents vomiting. Uncontrolled vomiting carries a high risk of aspiration, the inhalation of stomach contents into the lungs. The NG tube helps mitigate this serious complication by keeping the stomach empty. Tube placement is a standard component of conservative management for partial obstructions, allowing time for the blockage to potentially resolve.
Criteria for Removal: Determining the Tube’s Duration
The duration an NG tube remains in place is not fixed, but depends entirely on objective clinical signs that the obstruction is resolving. The tube’s stay is highly individualized, ranging from a few hours to several days. The goal is to remove the tube as soon as decompression is no longer needed, as prolonged placement increases discomfort and the risk of complications.
A primary indicator for removal is a significant decrease in the volume of fluid drained through the tube. Clinical guidelines often look for output to drop below a specific threshold, such as less than 100 to 200 milliliters over 24 hours. This reduction suggests that backed-up fluid is moving past the obstruction and through the digestive tract, rather than returning to the stomach.
The resolution of the patient’s physical symptoms is equally important. The physician monitors for the complete cessation of nausea and vomiting, along with a noticeable reduction in abdominal distention and tenderness. When the abdomen softens and the patient reports feeling less bloated, it suggests that the gut pressure has normalized.
The most definitive sign that the bowel is recovering is the return of coordinated digestive function. This is evidenced by the patient passing flatus, which confirms that air is successfully moving through the intestine. Following the passage of flatus, a spontaneous bowel movement confirms that the obstruction has cleared and the digestive tract has resumed normal activity.
Imaging studies, such as abdominal X-rays, may also be used to confirm the clinical assessment. An X-ray can show a reduction in the size of dilated bowel loops or the movement of ingested contrast material past the former blockage site. Once the medical team confirms these combined indicators—low output, symptom resolution, and return of bowel function—the NG tube is removed to promote patient comfort and recovery. For non-operative management, signs of resolution often appear within 24 to 72 hours.
Patient Experience and Tube Management
The insertion of an NG tube can be uncomfortable, as the tube passes through the nasal passage and the back of the throat. Patients often report feeling pressure and a strong gag reflex during the brief placement procedure. To manage this discomfort, a topical anesthetic spray, such as lidocaine, may be used to numb the nasal and throat tissues before insertion.
Once the tube is in place, it is secured to the nose with a specialized dressing or tape to prevent displacement. Despite proper securing, the tube often causes throat irritation and dry mouth, compounded by the patient remaining “nothing by mouth” (NPO). Frequent oral care, including brushing teeth, using mouthwash, and moisturizing the lips, is encouraged to maintain comfort and hygiene.
Patients must be aware of the tube’s function and the importance of not tampering with its placement or the continuous suction. Any discomfort or feeling that the tube has moved should be immediately communicated to the nursing staff. Gentle movement, such as walking, is often encouraged as it can help stimulate the return of normal bowel activity.
Recovery and Diet Progression After Removal
Once the NG tube is removed, the period of “gut rest” ends, and the patient begins a cautious progression of reintroducing food and fluids. This slow progression ensures the resolved obstruction does not recur and that the bowel can tolerate its workload. The initial step typically involves starting with small sips of water or allowing the patient to suck on ice chips.
The diet then advances to clear liquids, which are easily digestible and leave no undigested residue. This includes broths, clear juices like apple or white grape, and gelatins. If these are tolerated without the return of nausea, vomiting, or abdominal pain, the diet progresses to full liquids, adding items like milk, cream soups, and milkshakes.
The next stage involves soft, low-fiber foods, which are gentle on the recovering intestine. Examples include mashed potatoes, scrambled eggs, and well-cooked vegetables without skins. This step-by-step approach is maintained while the medical team watches closely for any signs of distress before moving to a regular diet.