How To Measure Ng Tube

How to Measure and Insert a Nasogastric (NG) Tube: A Comprehensive Guide

Measuring and inserting a nasogastric (NG) tube is a crucial skill for healthcare professionals, particularly nurses. This procedure, used to deliver medications, feedings, or remove stomach contents, requires precision and adherence to strict protocols to ensure patient safety and efficacy. This comprehensive guide will walk you through the process, covering everything from pre-procedure preparations to post-insertion verification. Understanding the proper techniques for NG tube measurement and insertion is vital for minimizing discomfort and complications for the patient.

I. Introduction: Understanding the Importance of Accurate NG Tube Measurement

Accurate measurement of the NG tube is the sine qua non of successful insertion. An improperly measured tube can lead to several complications, including:

Incorrect placement: The tube may end up in the lungs (leading to aspiration pneumonia), esophagus, or duodenum instead of the stomach.
Discomfort and pain: A tube that is too long or short can cause significant discomfort to the patient.
Tube blockage or kinking: An improperly positioned tube may become blocked or kinked, preventing the delivery of medications or feedings.
Nasoesophageal reflux: If the tube isn't properly placed in the stomach, stomach contents can reflux back into the esophagus.

Therefore, mastering the art of NG tube measurement is not just a technical skill; it’s a fundamental aspect of patient safety and comfort. This guide details the step-by-step process to ensure you confidently and accurately measure and insert an NG tube.

II. Pre-Procedure Preparations: Setting the Stage for Success

Before initiating the NG tube measurement and insertion, several vital preparatory steps must be followed:

Gather Supplies: This includes the NG tube itself (of appropriate size and material), measuring tape or ruler, water-soluble lubricant, gloves, an appropriate-sized syringe (for flushing and checking patency), a basin, tissues, patient identification band, patient chart, medication administration record, suction equipment (in case of aspiration), and a stethoscope.
Verify the Doctor's Order: Double-check the doctor's order for the NG tube insertion, ensuring you have the correct patient information, the type of tube, and the purpose of insertion.
Patient Identification and Consent: Confirm the patient's identity using two identifiers (e.g., name and date of birth) and obtain informed consent. Explain the procedure to the patient in clear, simple terms, answering any questions they may have. Address their anxieties and concerns.
Patient Assessment: Assess the patient's overall condition, including respiratory status, level of consciousness, and any potential contraindications (e.g., recent nasal surgery). Note any nasal abnormalities that might affect tube passage.
Hand Hygiene: Perform thorough hand hygiene using soap and water or an alcohol-based hand rub.

III. Measuring the NG Tube: A Critical Step

Accurate measurement is the cornerstone of a successful NG tube placement. There are two primary methods:

Method 1: Using the Distance from the Tip of the Nose to the Earlobe to the Xiphoid Process:
1. This is the most common method.
2. Use a flexible measuring tape.
3. Gently measure the distance from the tip of the patient's nose to the earlobe.
4. Next, measure from the earlobe to the xiphoid process (the bony projection at the bottom of the sternum).
5. Add the two measurements together. This total length represents the approximate length needed for the NG tube. It is crucial to remember this is an estimate.
6. Mark the measured length on the NG tube using a marker. This ensures accuracy and consistency.
Method 2: Using the Patient’s Height: Some institutions prefer using height-based charts to determine the appropriate NG tube length. This is generally based on the patient’s height and weight. These charts are typically available on unit-specific guidelines or facility policy and procedure manuals. This method should be used if the institution provides this as the preferred method.

Important Considerations:

Individual Variations: Keep in mind that these methods provide an estimate. Individual anatomical variations can affect the precise length needed. Therefore, continuous monitoring and verification of tube placement are essential after insertion.
Tube Length Markers: Most NG tubes have pre-marked length increments. Using these markings alongside your measurement can aid in accuracy.
Over-measurement is preferable to under-measurement: It’s better to have a slightly longer tube than risk it being too short. However, always avoid excessive length to prevent complications.

IV. NG Tube Insertion: A Step-by-Step Guide

Once the NG tube is accurately measured, follow these steps for insertion:

Position the Patient: Position the patient comfortably in a semi-Fowler's position (45-degree angle). This helps facilitate gravity-assisted passage of the tube.
Lubrication: Apply a generous amount of water-soluble lubricant to the tip of the NG tube. This reduces friction and discomfort during insertion.
Insertion: Gently insert the lubricated NG tube into one of the patient's nostrils, aiming towards the back of the throat. Advance the tube along the floor of the nasal passage. Avoid inserting the tube forcefully; this can cause trauma. If resistance is met, try the other nostril.
Patient Comfort: Encourage the patient to swallow small sips of water. Swallowing helps move the tube down the esophagus.
Continuous Monitoring: Observe the patient for any signs of distress, such as coughing, choking, or cyanosis. Immediately stop the procedure if any of these signs appear.
Marking the Insertion Point: Once you reach the pre-marked length on the NG tube, secure the tube with tape.

V. Verification of NG Tube Placement: Ensuring Correct Position

Aspirate Stomach Contents: After insertion, use a syringe to aspirate stomach contents. The presence of gastric contents (usually a yellowish or greenish fluid with a pH of less than 5) is a strong indicator of proper placement.
pH Testing: Test the aspirated fluid using a pH testing strip. A pH below 5 suggests that the tube is in the stomach. A pH above 6 suggests that the tube may not be correctly placed and should be investigated further.
X-ray Confirmation: While aspirating and pH testing are standard practices, a chest x-ray is considered the gold standard for verifying NG tube placement. This provides visual confirmation of the tube's location. Always check your facility's policy regarding this.
Auscultation: While less reliable, auscultation (listening with a stethoscope while injecting air into the tube) can sometimes provide a confirmation of correct placement. The presence of air sounds over the epigastric region suggests the tube is in the stomach.

VI. Post-Insertion Care: Maintaining Patency and Comfort

After successful NG tube insertion and placement verification, the following steps are crucial:

Securing the Tube: Secure the tube to the patient's nose using appropriate tape to prevent accidental removal.
Marking the Insertion Point: Clearly mark the tube’s exit point on the patient's nose.
Monitoring for Complications: Regularly monitor the patient for any signs of complications, including discomfort, aspiration, tube displacement, or infection.
Routine Flushing: Flush the tube with water or saline regularly as per the physician's order to maintain patency. This prevents blockage.
Patient Education: Educate the patient and their family about the NG tube, its purpose, and any potential complications.

VII. Scientific Explanation: The Anatomy and Physiology of NG Tube Placement

The successful placement of an NG tube relies on understanding the basic anatomy and physiology of the upper gastrointestinal tract. The tube passes through the nasal passages, then into the pharynx, bypassing the larynx to avoid the airway. Successful passage down the esophagus depends on the ability to avoid the esophageal sphincter which can impede the tube. It finally ends in the stomach. The stomach is recognized through its characteristic ph level. The esophageal-gastric junction can also be felt by a small resistance, however, this is not a reliable indicator.

Accurate placement avoids potential complications such as aspiration pneumonia (the tube entering the lungs), esophageal irritation, and nasal trauma.

VIII. Frequently Asked Questions (FAQs)

Q: What happens if the NG tube is placed incorrectly?

A: Incorrect placement can lead to aspiration pneumonia (if the tube enters the lungs), esophageal damage, or ineffective medication or feeding delivery. Immediate removal and re-insertion or an alternative feeding method may be necessary.
Q: What are the common complications associated with NG tube insertion?

A: Potential complications include nasal irritation, epistaxis (nosebleed), esophageal trauma, aspiration pneumonia, infection at the insertion site, and tube blockage or displacement.
Q: How long can an NG tube remain in place?

A: The duration of NG tube placement varies depending on the patient's condition and the reason for insertion. It can range from a few days to several weeks.
Q: How often should the NG tube be flushed?

A: The frequency of flushing depends on the physician's order and the type of feeding or medication being administered. It is typically done before and after medication administration and feeding.
Q: What if I encounter resistance during insertion?

A: If you encounter significant resistance, stop the insertion. This could indicate anatomical abnormalities or an obstruction. Attempt insertion into the other nostril, or consult a more experienced colleague or physician.

IX. Conclusion: Mastering the Art of NG Tube Measurement and Insertion

Measuring and inserting a nasogastric tube is a critical skill for healthcare professionals. While this guide provides a comprehensive overview, hands-on training and supervised practice are essential for competency. Adherence to standardized procedures, careful attention to detail, and continuous monitoring are vital for ensuring patient safety and optimal outcomes. Remember, accurate measurement is the first step towards successful NG tube placement, minimizing risks and maximizing comfort for your patients. Thorough understanding of the anatomy, consistent adherence to protocols, and regular practice are key to mastering this vital skill. Patient safety should always be your top priority.