A nasogastric (NG) tube is a slender, flexible tube inserted through the nose, down the esophagus, and into the stomach. This medical device serves several important functions, most commonly providing nutritional support and medication to patients who cannot safely swallow food or liquids by mouth. NG tubes are also frequently used for gastric decompression, which involves suctioning out stomach contents like air and fluid to relieve pressure, particularly in cases of bowel obstruction or after major surgery.
For instance, a Salem sump tube, a common type, has a double lumen allowing for continuous suctioning with an air vent. Inserting an NG tube is a highly skilled medical procedure performed exclusively by trained healthcare professionals. This information is for educational purposes only and should never be used for self-insertion or attempted without professional training.
Essential Preparation and Measurement
Necessary supplies must be gathered, including the NG tube, water-soluble lubricant, a syringe, a stethoscope, securing tape, and personal protective equipment. The patient must be positioned correctly, typically in a High Fowler’s position (60 to 90-degree angle), to facilitate the tube’s passage down the esophagus using gravity.
Determining the correct insertion length is crucial to ensure the tube tip reaches the stomach without coiling or entering the small intestine. The traditional method for estimating this length is the Nose-to-Ear-Lobe-to-Xiphoid process, or NEX measurement. This technique involves measuring the distance from the patient’s nostril, extending it to the earlobe, and then continuing the measurement down to the xiphoid process, which is the lower tip of the sternum.
Once measured, a mark is placed on the tube to serve as a guide during insertion. While the NEX method is widely used, it has been shown to underestimate the required length in some patients. Before proceeding, the most patent nostril is identified by asking the patient to occlude each side and breathe, and the nostril may be lubricated or anesthetized to minimize discomfort.
Step-by-Step Insertion Procedure
Insertion begins by generously lubricating the first three to four inches of the tube tip with a water-soluble gel to minimize friction. The lubricated tip is gently inserted into the selected nostril, following the natural curvature of the nasal floor and aiming straight back towards the ear. If resistance is met, the tube should be slightly withdrawn and re-angled, or the other nostril should be used, because forcing the tube can cause trauma or deviation.
As the tube advances into the nasopharynx, the patient may experience a gag reflex, indicating the tube is nearing the back of the throat. The patient is instructed to tuck their chin down toward their chest; this maneuver anatomically closes the trachea and opens the esophagus. The patient should then be encouraged to swallow small sips of water or perform dry swallows to help guide the tube down the correct pathway.
The tube is advanced in coordination with each swallow, utilizing the esophagus’s peristaltic action to move the tube into the stomach. Pause immediately if the patient begins to cough, choke, or show signs of respiratory distress, as this indicates the tube may have entered the trachea or lungs. Once the tube reaches the pre-measured mark, the insertion is complete, and the tube must be secured provisionally until placement verification is performed.
Confirming Correct Placement
Verification of the tube’s final position is the most important safety step, as administering substances into a tube coiled in the lungs can be fatal. The gold standard method for confirming correct NG tube placement, particularly before initial use, is a chest X-ray. Radiographic confirmation allows providers to visualize the tube’s course and confirm that the tip has passed the diaphragm and is situated correctly in the stomach.
While X-ray confirmation is definitive, bedside methods are often used for initial checks and re-confirmation. Aspiration of gastric contents is a reliable technique where a syringe is used to draw fluid from the tube. If the tube is correctly positioned, the aspirate will typically be clear, cloudy, or yellow-green stomach fluid. The most reliable bedside test involves checking the pH level of this aspirated fluid using specialized indicator strips. Gastric fluid in a fasting patient is highly acidic, usually registering a pH of 5.5 or lower, indicating correct placement.
Auscultation, which involves injecting air into the tube while listening over the abdomen with a stethoscope, is often discouraged by current guidelines. Although a whooshing sound may be heard if the tube is in the stomach, a similar sound can be produced if the tube is in the esophagus, making this test unreliable. No feeding or medication should be administered until the tube’s position is safely confirmed, ideally through pH testing and X-ray, to prevent pulmonary aspiration.
Ongoing Tube Management and Removal
After placement is confirmed, the NG tube must be securely fastened to the patient’s nose and cheek to prevent tension and accidental dislodgement. Specialized adhesive devices or hypoallergenic tape are used to create a secure anchor, and the tube should also be pinned to the patient’s gown. The external measurement mark on the tube should be checked regularly against the nostril to detect any migration.
Maintaining the tube’s patency is achieved through routine flushing with water. Flushing should occur before and after every medication dose or feeding, and at least every four to six hours during continuous feeding, typically using 30 milliliters of water. This irrigation prevents the buildup of formula or crushed medication that can clog the tube’s narrow lumen.
Throughout the time the tube is in place, the patient and the insertion site must be monitored for signs of complications, such as nasal irritation, coughing, or difficulty breathing, which may signal tube displacement or a developing complication. When the tube is no longer required, removal is a quick, straightforward process. The tube is disconnected from any apparatus, and the securing tape is removed. The patient is instructed to take a deep breath and hold it to close the epiglottis, and the healthcare provider rapidly and smoothly pulls the tube out in one continuous motion.