A nasogastric (NG) tube is a flexible tube inserted through the nose into the stomach. The primary function of connecting it to suction is gastric decompression, which removes accumulated air and fluid. This procedure relieves uncomfortable symptoms like bloating, nausea, and vomiting, often caused by a blockage or slowed digestive system. Removing gastric contents also helps prevent aspiration, where stomach contents enter the lungs.
Necessary Preparation and Equipment Check
Before connecting the NG tube to suction, proper preparation ensures patient safety and procedural success. Begin with hand hygiene and position the patient in a semi-Fowler’s position (head of the bed elevated 45 to 90 degrees). This upright posture facilitates drainage and minimizes the risk of fluid reflux and aspiration.
Specialized equipment is needed to complete the connection safely. This includes the NG tube, a suction machine or wall suction source, the collection canister, suction tubing, and a specialized connector piece. You will also need clean gloves, a securing device or tape, and a large 60-milliliter syringe to check for tube patency.
Checking that the tube is patent, or clear, is an essential pre-step. Gently attempt to aspirate stomach contents using the 60-milliliter syringe; resistance indicates the tube may be kinked or blocked. Also, check the external length marking at the nostril to confirm the tube has not moved since placement.
The Physical Connection Process
Once materials are ready and patency is confirmed, the physical connection can begin. The NG tube typically has two ports: the main, larger lumen used for suction, and a smaller auxiliary lumen, often called the “sump” or “pigtail,” which acts as an air vent. Connect the suction tubing only to the main, larger suction lumen.
The auxiliary air vent prevents the tube from creating a vacuum and suctioning the stomach lining; therefore, this port must never be clamped or connected to the suction source. Attach the suction tubing to the main NG tube port, often using a connector to ensure a snug fit. This connection must be secure and airtight to maintain the necessary negative pressure for effective suctioning.
Next, connect the suction tubing to the collection canister, which is seated in the suction machine or attached to the wall unit. The tubing from the NG tube attaches to the canister port labeled “patient.” A second length of tubing connects the canister’s “vacuum” port to the actual suction source, and verifying the canister lid is sealed completes the circuit.
Operating and Monitoring Suction Settings
Once the physical connection is secure, turn on the suction device and apply the appropriate setting. Nasogastric decompression typically uses low suction pressure to minimize damage to the gastric mucosa. The pressure setting is usually set within the low range of 40 to 80 millimeters of mercury (mmHg), often starting between 40 and 60 mmHg.
Suction is applied using one of two methods: continuous or intermittent. Continuous suction provides an uninterrupted flow of negative pressure, typically reserved for high-volume drainage or when rapid decompression is required. Intermittent suction applies negative pressure in cycles, turning on and off, and is the preferred method for most patients to prevent the suction eyelets from adhering to the stomach wall.
Once the machine is operating, observe the tubing for the flow of gastric contents into the collection canister. Regular monitoring of the drainage is necessary, including checking the volume, color, and consistency of the fluid, often every eight hours or as directed. Any sudden change in the amount or appearance of the drainage should be noted and reported.
Identifying and Addressing Complications
Even with careful management, complications such as tube blockage or patient discomfort can occur during NG suctioning. If drainage suddenly stops, first check the tubing for any visible kinks or bends. A lack of output accompanied by renewed abdominal distension, nausea, or cramping signals a potential obstruction or tube migration.
If a blockage is suspected, attempt to clear the tube by gentle irrigation, using a large 60-milliliter syringe and 30 to 60 milliliters of warm water. Use a gentle push-pull motion on the syringe plunger to dislodge the obstruction, but never use excessive force, as this can damage the tube or stomach lining. If this fails to restore patency, or if the patient reports worsening pain, the suction must be immediately turned off.
Tube displacement is a concern, suspected if the external length marking has changed or if the patient begins to cough or experience respiratory distress. If you cannot clear a blockage with gentle irrigation, or if you suspect the tube has moved, immediately disconnect the NG tube from the suction. In any situation involving persistent blockage, excessive drainage volume, or signs of tube migration, contact a healthcare professional for guidance.