A nasogastric (NG) tube is a flexible plastic device inserted through the nose, down the throat, and into the stomach. This common medical procedure serves several distinct purposes in patient care. The tube delivers liquid nutrition and medications directly into the digestive system when a person cannot eat or swallow safely. It is also utilized to remove stomach contents, a process known as gastric decompression, which relieves pressure from accumulated air or fluids, often in cases of bowel obstruction or after surgery.
Preparing for NG Tube Insertion
Careful preparation of the patient and equipment is necessary before insertion. The patient is typically positioned in a high Fowler’s position, seated upright with the head of the bed raised between 45 and 90 degrees. This upright posture utilizes gravity and helps prevent the tube from accidentally passing into the trachea.
The correct length for insertion must be accurately measured using the NEX method. This involves extending the tube from the tip of the patient’s nose (N) to the earlobe (E), and then down to the xiphoid process (X) at the bottom of the sternum. Marking this measurement on the tube provides a target length to guide the insertion.
Necessary equipment includes the tube, a water-based lubricant, a syringe, and an emesis basin. Check the patency of each nostril to select the most open passage for the tube. Lubricating the tip reduces friction and irritation within the nasal passage.
The Step-by-Step Insertion Process
Gently introduce the lubricated tip of the tube into the chosen nostril, directing it along the floor of the nasal cavity. Advance the tube slowly, aiming toward the ear on the same side to follow the natural curvature of the nasal passage. This initial movement requires steady, gentle pressure.
Once the tube reaches the back of the throat (nasopharynx), the patient may experience a strong gag reflex, causing coughing or watering of the eyes. Instruct the patient to tuck their chin toward their chest. This maneuver helps close off the trachea and encourages the tube to enter the esophagus, minimizing the risk of airway entry.
To facilitate the tube’s descent into the esophagus, the patient is asked to swallow repeatedly, often by sipping water or dry swallowing. Each swallow helps the epiglottis close over the trachea, guiding the tube. Advance the tube only a few centimeters with each swallow.
If the patient begins coughing severely, shows signs of respiratory distress, or the tube meets significant resistance, stop immediately and withdraw the tube slightly. These signs indicate the tube may have entered the trachea, requiring immediate correction. Insertion continues until the pre-measured length mark reaches the nostril, suggesting the tip is within the stomach.
Confirming Proper Placement
Verifying the NG tube’s position within the stomach is essential, as misplacement into the lungs can lead to severe complications. The gold standard method for confirmation is a chest X-ray, which provides the tube’s tip location. An X-ray is mandatory before the initial use of a feeding tube.
A common bedside method involves aspirating a small fluid sample from the tube using a syringe. The appearance of the fluid offers a preliminary clue, as gastric contents are typically clear, grassy green, or yellow-tinged. This aspirated fluid is then tested using a specialized pH strip.
Stomach contents are highly acidic; a pH reading of 5.5 or lower generally confirms gastric placement. However, medications or continuous feeding can alter stomach pH, making testing less reliable in some populations. The auscultatory method, involving injecting air and listening over the stomach, is unreliable and should not be used as the sole confirmation method due to its high rate of false-positive results.
Immediate Care and Monitoring
Once gastric placement is confirmed, secure the tube firmly to the nose or cheek using a specialized fixation device or non-irritating tape. Securing the tube prevents accidental dislodgement or migration and protects the nasal tissue from irritation caused by tube movement.
Patients often experience dryness of the mouth and throat because the tube encourages mouth breathing and restricts oral intake. Frequent oral hygiene, including brushing the teeth and rinsing the mouth, is important for comfort and preventing infection. Some patients may suck on ice chips to relieve thirst, provided they can safely manage the melted water without swallowing.
Ongoing monitoring is necessary to detect potential complications and signs of tube migration. A sudden onset of coughing, difficulty breathing, or a change in the external length of the tube requires immediate attention, as these symptoms suggest the tube may have moved out of the stomach. The head of the bed should remain elevated to a minimum of 30 degrees at all times to reduce the risk of aspiration.