Orogastric (OG) tube placement is common in mechanically ventilated patients. The primary function of the OG tube is gastric decompression, removing air and fluid from the stomach to prevent distension and reduce aspiration risk. The tube also provides a secure route for administering medications and enteral nutrition. The oral route is chosen over the nasal route because the Endotracheal Tube (ETT) occupies the pharynx and trachea. Using the oral passage avoids complications associated with Nasogastric Tube (NGT) insertion, such as nasal trauma, bleeding, and sinusitis. This procedure requires precision to ensure the tube is correctly positioned in the stomach and not misplaced into the respiratory tract.
Essential Preparation and Tube Measurement
Preparation begins with an equipment check and patient positioning. Necessary items include the Orogastric tube (typically 14-18 French for decompression), water-soluble lubricating gel, a 60-mL catheter-tip syringe, and securing materials to prevent migration. The patient should be supine, with the bed’s head elevated slightly (often 30 degrees) to help prevent reflux.
The most important pre-insertion step is accurately determining the required insertion length. For intubated adults, the length is estimated by measuring the distance from the patient’s earlobe to the xiphoid process (the lower tip of the sternum). This measurement provides the foundational estimate of the distance to the stomach. The calculated length is then marked on the tube with tape or a marker. A safety margin, often 10 centimeters, should be added to ensure the tube’s distal side holes pass completely through the gastro-esophageal junction. Underestimation risks the tube remaining in the esophagus, compromising functionality and increasing aspiration risk.
Step-by-Step Insertion Technique
Insertion requires a careful and gentle approach due to the presence of the ETT. Lubricate the distal tip of the OG tube generously with water-soluble gel to reduce friction and minimize mucosal trauma. Perform a jaw thrust by grasping the patient’s mandible and gently pulling it forward. This maneuver opens the oropharynx and aligns the esophagus, creating a more direct path.
The lubricated tube is inserted orally and advanced toward the back of the throat. A highly effective technique uses the index finger of the non-dominant hand as a guide, inserting it to feel for the ETT and direct the OG tube posteriorly along its side. This manual guidance ensures the tube passes over the epiglottis and into the esophagus, which lies posterior to the trachea. The inflated ETT cuff offers a protective barrier against accidental tracheal placement.
Advance the tube steadily and smoothly, aiming posteriorly and inferiorly toward the esophagus. Pay close attention to any resistance encountered. Significant resistance suggests the tube is coiling or impacting a structure; withdraw it slightly, rotate, and re-advance. Force must never be used, as this risks perforation or injury. Advance the tube until the pre-measured mark reaches the patient’s lips.
During insertion, continuously monitor the patient’s vital signs and ventilator pressures. An increase in airway pressure or a drop in oxygen saturation could indicate the tube has inadvertently entered the trachea, obstructing airflow. Once the tube reaches the pre-measured mark, the insertion phase is complete.
Confirmation and Stabilization
Confirmation of the tube’s location is mandatory before using the OG tube for feeding or medication administration. The gold standard for confirming placement is a chest and abdominal radiograph (X-ray). The X-ray provides a clear, visual image of the tube’s course, confirming that the tip is correctly positioned below the diaphragm and within the gastric bubble. Before obtaining the X-ray, initial bedside methods are employed to rule out immediate misplacement into the respiratory tract.
Bedside Confirmation Methods
One technique involves aspirating contents from the tube using a syringe. The appearance of gastric fluid (typically cloudy, green, or yellow-tan) suggests correct placement. This aspirate should be tested with pH indicator paper; a pH value of 5.0 or less strongly indicates gastric placement, as the stomach is naturally acidic.
The auscultatory technique involves rapidly injecting 10 to 30 milliliters of air into the tube while listening with a stethoscope over the patient’s epigastrium (upper abdomen). A distinct gurgling sound suggests the air has entered the stomach. However, this technique is known to be unreliable and should never be used as the sole method of confirmation.
Once correct placement is confirmed, the tube must be secured firmly to the patient’s face to prevent accidental dislodgement or migration. The OG tube can be taped to the cheek or secured to the existing ETT holder, ensuring that the tape does not cause pressure on the lips or corners of the mouth. Finally, the measurement of the tube length visible from the patient’s lips must be documented in the patient’s chart. This documentation provides a baseline measurement for all future checks, helping to quickly identify if the tube has moved.