KEY STEPS IN NASOGASTRIC TUBE INSERTION: A PRACTICAL APPROACH FOR NURSES AND DOCTORS

The insertion of a nasogastric (NG) tube is a common medical procedure performed across various healthcare settings. An NG tube is a flexible plastic tube passed through the nostril, down the pharynx and esophagus, and into the stomach. This procedure is critical for several therapeutic and diagnostic purposes, requiring meticulous technique, thorough understanding, and a commitment to patient safety and comfort.

Introduction to Nasogastric Tubes

Nasogastric tubes serve multiple vital functions in patient care. They can be used for gastric decompression in cases of bowel obstruction or ileus, administration of medications and enteral nutrition (tube feeding) when oral intake is impossible or unsafe, aspiration of gastric contents for diagnostic analysis, and gastric lavage in situations of poisoning or overdose. The judicious application of this procedure necessitates a robust understanding of its indications, contraindications, and the precise steps involved to ensure efficacy and minimize patient discomfort and risks. Proper technique is paramount to prevent adverse events such as respiratory aspiration, esophageal trauma, or incorrect tube placement.

Indications for Nasogastric Tube Insertion

The decision to insert an NG tube is guided by specific clinical situations:

1. Enteral Nutrition: For patients unable to ingest food orally due to conditions like dysphagia, altered consciousness, severe anorexia, or critical illness, NG tubes provide a temporary route for nutritional support.
2. Gastric Decompression: In cases of gastrointestinal obstruction, paralytic ileus, or gastric dilation, an NG tube can decompress the stomach and intestines, reducing nausea, vomiting, and abdominal distension.
3. Medication Administration: When oral medication is contraindicated or impossible, an NG tube allows the delivery of liquid formulations directly into the stomach.
4. Gastric Lavage: In emergency situations involving poisoning or overdose, an NG tube is used to irrigate the stomach to remove harmful substances.
5. Diagnostic Purposes: Aspiration of gastric contents can be performed to analyze gastric pH, obtain samples for microbiological studies, or assess for upper gastrointestinal bleeding.
6. Prevention of Aspiration: In post-operative settings or for intubated patients, NG tubes can reduce the risk of aspiration by emptying gastric contents.

Contraindications for Nasogastric Tube Insertion

While generally safe, NG tube insertion is contraindicated in certain conditions due to the risk of severe complications:

1. Severe Facial or Head Trauma: Especially fractures involving the cribriform plate, which could lead to intracranial insertion of the tube.
2. Esophageal Strictures or Obstruction: Conditions like esophageal cancer, large diverticula, or varices increase the risk of perforation.
3. Recent Esophageal or Gastric Surgery: May compromise the surgical site’s integrity.
4. Basilar Skull Fracture: High risk of intracranial tube placement.
5. Cocaine Use: May cause nasal septum perforation.
6. Coagulation Abnormalities: Increased risk of bleeding from nasal or esophageal trauma.
7. Uncontrolled Vomiting: Can increase the risk of aspiration during insertion.
8. Unprotected Airway: Patients with impaired gag reflex or altered consciousness without intubation are at high risk of aspiration.

Essential Equipment

Before initiating the procedure, gather all necessary equipment to ensure a smooth and efficient process:

• Nasogastric Tube: Appropriate size (adults typically 14-18 Fr; pediatric sizes vary). Salem sump tubes are commonly used for decompression due to their dual lumen (main lumen for aspiration, smaller lumen for air vent).
• Water-Soluble Lubricant: Essential for reducing friction and discomfort during insertion.
• Towel or Chux Pad: To protect the patient’s clothing and bedding from secretions.
• Emesis Basin: For potential nausea or vomiting.
• Glass of Water with Straw: For patient sips during insertion, if not contraindicated.
• Syringe (60 mL, Toomey or catheter tip): For aspiration of gastric contents and air insufflation.
• pH Indicator Strips: To test the acidity of aspirated fluid.
• Non-Allergenic Tape or NG Tube Securement Device: To secure the tube in place.
• Stethoscope: For auscultation during air insufflation (though less reliable for confirmation).
• Personal Protective Equipment (PPE): Gloves, eye protection, and gown as per universal precautions.
• Flashlight/Penlight: To assess the oral cavity.
• Suction Equipment (optional but recommended): In case of aspiration.
• Topical Anesthetic Spray (e.g., lidocaine): To numb the nostril and pharynx, reducing discomfort (use with caution and physician order).

Patient Preparation

Thorough patient preparation is crucial for a successful and tolerable procedure:

1. Verify Order: Confirm the physician’s order for NG tube insertion, including the type and purpose.
2. Patient Identification: Verify the patient’s identity using two identifiers.
3. Explain Procedure: Clearly explain the procedure, its purpose, and what the patient can expect. Address any concerns or questions. Emphasize cooperation, particularly regarding swallowing.
4. Assess Allergies: Document any allergies to latex, tape, or local anesthetics.
5. Assess Nasal Patency: Ask the patient to occlude one nostril at a time and breathe through the other. Choose the more patent nostril. Inspect for septum deviation, polyps, or trauma.
6. Position Patient: Assist the patient into a high-Fowler’s position (head of bed elevated 45-90 degrees) or sitting upright. This position aids gravity and helps prevent aspiration.
7. Provide Privacy: Close curtains or doors.
8. Place Towel: Drape a towel or chux pad over the patient’s chest.
9. Prepare Emesis Basin: Place it within the patient’s reach.

Procedure: Step-by-Step Guide for NG Tube Insertion

1. Hand Hygiene and PPE: Perform thorough hand hygiene and don appropriate PPE (gloves, eye protection).
2. Measure the Tube: This is a critical step to ensure the tube reaches the stomach without being too short or too long.
   • Place the tip of the NG tube at the tip of the patient’s nose.
   • Extend the tube to the earlobe.
   • Continue extending the tube from the earlobe to the xiphoid process (the inferior tip of the sternum). This is often referred to as the “NEX” measurement (Nose-Earlobe-Xiphoid).
   • Mark this length on the tube with a piece of tape or a permanent marker. This mark indicates the approximate depth for gastric placement.
3. Lubricate the Tube: Apply copious amounts of water-soluble lubricant (at least 2-4 inches) to the distal end of the tube. This reduces friction and minimizes discomfort and trauma during insertion. Local anesthetic spray can be applied to the nostril and posterior pharynx at this stage, if ordered.
4. Insert into Nares:
   • Gently insert the lubricated tip of the NG tube into the chosen nostril, directing it posteriorly and slightly inferiorly, following the natural curvature of the nasal passage.
   • If resistance is encountered, do not force the tube. Withdraw slightly, re-lubricate, and try redirecting or using the other nostril.
5. Advance to Nasopharynx:
   • Once the tube reaches the nasopharynx (typically after 5-6 inches), you may feel slight resistance.
   • At this point, instruct the patient to tuck their chin towards their chest (“chin to chest” position). This manoeuvre helps close the trachea and open the esophagus, facilitating correct passage.
   • Ask the patient to swallow sips of water through a straw, if permitted, or perform dry swallows. Each swallow helps propel the tube down the esophagus.
6. Continue Advancing:
   • Continue to advance the tube gently, coordinating with the patient’s swallowing efforts.
   • Observe the patient closely for signs of distress. If the patient begins to cough excessively, choke, experience respiratory distress (e.g., dyspnea, cyanosis), or their voice changes (hoarseness), immediately withdraw the tube. These signs indicate possible tracheal intubation. Allow the patient to recover before attempting re-insertion if necessary.
7. Advance to Marked Length: Continue advancing the tube until the pre-measured mark reaches the nostril.
8. Temporary Securement: Once the tube is inserted to the appropriate depth, temporarily secure it to the patient’s nose with a small piece of tape to prevent accidental dislodgement before confirming placement.

Confirmation of Tube Placement (Crucial for Patient Safety)

Accurate confirmation of NG tube placement is paramount to prevent adverse events, especially pulmonary aspiration. Never assume correct placement based solely on visualization or patient tolerance.

1. X-ray Verification (Gold Standard): A chest X-ray is the most reliable method to confirm NG tube placement in the stomach or small intestine. It is mandatory before initiating feeds or medications, especially for critically ill patients or those with impaired consciousness.
2. Aspiration of Gastric Contents:
   • Attach the 60 mL syringe to the end of the NG tube.
   • Gently aspirate gastric contents. The presence of green, yellow, brown, or clear fluid is suggestive of gastric placement. Note: Absence of aspirate does not definitively rule out gastric placement, as the tube may be against the stomach wall.
3. pH Testing:
   • Place a drop of the aspirated fluid onto pH indicator paper.
   • Gastric fluid typically has an acidic pH (0-5.5). Pleural fluid (if in the lungs) or intestinal fluid usually has a pH ≥6. Tracheobronchial fluid is generally alkaline (pH ≥7).
   • Caution: Patients on acid-suppressing medications (e.g., proton pump inhibitors, H2 blockers) may have a higher gastric pH, making this method less reliable.
4. Air Insufflation (Not Recommended as Primary Method):
   • Inject 10-30 mL of air into the NG tube rapidly with the syringe while auscultating over the epigastrium with a stethoscope. A “whoosh” sound is commonly associated with gastric placement.
   • Caution: This method is unreliable and should never be used as the sole determinant of placement, as a “whoosh” sound can be heard even if the tube is in the esophagus or lungs. It is associated with a high rate of false positives and negatives.
5. Visual Inspection of Oropharynx: Briefly inspect the back of the patient’s throat with a flashlight to ensure the tube is not coiled in the pharynx.

Securing the Tube

Once placement is confirmed by X-ray, secure the NG tube firmly to the patient’s nose to prevent dislodgement:

• Use a suitable NG tube securement device or non-allergenic tape.
• Fashion a “pant leg” or “Y” shape with tape, applying one strip horizontally across the nose and wrapping the split ends around the tube.
• Ensure the tape is secure but not irritating to the skin. Change the tape daily and inspect the skin for pressure areas or breakdown.
• Secure the remaining length of the tube to the patient’s gown to prevent tension on the nostril.

Post-Procedure Care and Documentation

1. Connect to Suction/Feeding: Once secured and placement confirmed, connect the tube to the prescribed suction settings or initiate feeding as ordered.
2. Patient Comfort: Provide oral hygiene, as NG tubes can cause dry mouth and throat irritation. Offer throat lozenges or ice chips if permitted.
3. Monitoring: Monitor the patient for any signs of discomfort, nasal irritation, abdominal distension, nausea, or displacement of the tube.
4. Documentation: Document the date and time of insertion, type and size of the tube, length inserted, nostril used, amount and characteristics of aspirated fluid, pH of aspirate, method of confirmation (especially X-ray), patient tolerance, and any complications.

Potential Complications

Despite best efforts, complications can occur:

• Aspiration: Gastric contents entering the lungs, a severe and potentially fatal complication.
• Nasal/Pharyngeal Trauma: Epistaxis, mucosal irritation, ulceration, or perforation.
• Esophageal Perforation: Rare but serious.
• Tracheal Intubation: Tube inadvertently inserted into the respiratory tract.
• Discomfort/Pain: Sore throat, nasal irritation.
• Sinusitis/Otitis Media: Due to obstruction of nasal passages.
• Electrolyte Imbalance: Particularly with prolonged gastric decompression.

Removal of NG Tube

Removing an NG tube is typically a straightforward process:

1. Verify the order for removal.
2. Explain the procedure to the patient.
3. Position the patient in a high-Fowler’s position.
4. Don gloves.
5. Disconnect the tube from suction/feeding.
6. Remove the tape or securement device from the nose.
7. Instruct the patient to take a deep breath and hold it (to close the epiglottis).
8. Rapidly and smoothly withdraw the tube.
9. Provide oral hygiene and document removal details.

Conclusion

Nasogastric tube insertion is a foundational skill for healthcare professionals, demanding precision, patient-centered care, and a thorough understanding of anatomical landmarks and physiological responses. Adhering to the step-by-step procedure, prioritizing patient comfort, and meticulously confirming tube placement (with X-ray as the gold standard) are non-negotiable elements for ensuring safety and optimizing patient outcomes. Continuous assessment, vigilance for complications, and comprehensive documentation further underscore the professional responsibility associated with this essential medical intervention. Healthcare providers must receive appropriate training and demonstrate competency before performing this procedure independently.

References

1. Crispin, S., & Miller, H. (2022). Nasogastric Tube Insertion. StatPearls [Internet]. Retrieved from https://www.ncbi.nlm.nih.gov/books/NBK535391/
2. Metheny, N. A., & Meert, K. L. (2014). A review of current techniques to detect feeding tube misplacement. AACN Advanced Critical Care, 25(4), 302-312.
3. Phillips, M. A., & Compher, C. W. (2018). Aspire to Inspire. Nutrition in Clinical Practice, 33(4), 543-551.
4. Royal College of Nursing. (2016). Guidance for Nurses on the Insertion and Ongoing Care of Nasogastric Tubes in Adults. Retrieved from https://www.rcn.org.uk/__data/assets/pdf_file/0009/786481/NG_tube_guidance.pdf
5. The Joint Commission. (2016). Quick Safety: Preventing Enteral Feeding Misconnections. Issue 27. Retrieved from https://www.jointcommission.org/-/media/tjc/newsletters/qs_27_enteral_feeding_final.pdf