A nasogastric (NG) tube is a flexible, small-bore medical device inserted temporarily through the nose, down the throat and esophagus, and into the stomach. Blind insertion refers to placing this tube without visual guidance tools, such as an endoscope or X-ray imaging. Instead, the healthcare provider relies on anatomical measurements and the patient’s cooperation to guide the tube to the stomach. This non-visualized technique is common in emergency and inpatient settings due to its speed and relative simplicity.
Defining the Nasogastric Tube and Its Uses
The NG tube establishes a direct connection to the stomach for various medical purposes. One frequent indication is gastric decompression, which involves connecting the tube to suction to remove accumulated air, fluid, or secretions from the stomach. This relieves pressure and distention in patients with a bowel obstruction or ileus. The tube also provides temporary nutrition (enteral feeding) for individuals who cannot safely consume food by mouth, such as those with swallowing difficulties (dysphagia) or those who are unconscious. Furthermore, the nasogastric route allows for the administration of liquid medications and the removal of toxic substances, such as in cases of accidental poisoning.
The “Blind” Insertion Procedure
The blind insertion technique begins with the patient sitting upright in the high Fowler’s position to align the digestive tract. Before placement, the required length is estimated using the NEX method, measured from the tip of the nose, looped to the earlobe, and extended down to the xiphoid process, which is the bottom tip of the sternum.
The tip of the tube is lubricated with a water-soluble gel to reduce friction and minimize discomfort as it passes through the nasal cavity. The tube is gently advanced along the floor of the chosen nostril until it reaches the nasopharynx. At this point, the patient is asked to flex their head forward, tucking their chin toward their chest, and to swallow small sips of water.
Swallowing temporarily closes the trachea (windpipe) and opens the esophagus, the correct path to the stomach. The tube is advanced a few centimeters with each swallow until the pre-measured mark reaches the nostril. If the patient coughs severely, chokes, or shows signs of breathing distress, the provider immediately stops and withdraws the tube, as this indicates potential airway entry.
Confirming Tube Placement
Following a blind insertion, confirming the tube’s final location is a safety step to ensure the tip is securely in the stomach and not misplaced into the lungs. The most reliable immediate bedside method involves aspirating fluid from the tube and testing its acidity using a pH strip. A highly acidic gastric aspirate (pH 1.0 to 5.5) confirms the tube is in the stomach.
An older, less reliable method involves injecting air into the tube while listening over the stomach with a stethoscope, but this auscultation technique is no longer recommended as a sole confirmation method. The definitive method for confirming tube placement, particularly before administering feed or medications, is a chest X-ray. The X-ray provides a visual confirmation that the tube has followed the esophagus, crossed the diaphragm in the midline, and that its tip is clearly visible below the left hemi-diaphragm.
Living with a Nasogastric Tube
The NG tube is secured to the cheek or nose with medical tape or a fixation device to prevent displacement, tracked by noting the centimeter mark at the nostril. The head of the bed must be elevated to at least 30 degrees, especially during and after feeding, to reduce the risk of stomach contents entering the lungs.
Routine care involves flushing the tube with a small amount of water several times a day or before and after use to prevent clogging. Patients may experience temporary side effects, including mild nasal irritation, a sore throat, or a sinus infection. Skin care around the nostril is important to prevent pressure ulcers, and the tube may need periodic relocation to the other nostril. The NG tube is intended for short-term use and is removed once the underlying condition that necessitated its placement has resolved.