From the Guidelines
To evaluate nasogastric (NG) tube placement, a radiograph, specifically a chest X-ray, is the gold standard and should be ordered. This is based on the most recent evidence from the Journal of the American College of Radiology, which states that radiographs can visualize the course of the nasogastric tube, confirming its proper placement 1. The recommended imaging study should include visualization of the chest and upper abdomen to confirm the NG tube's position.
When ordering this X-ray, it is essential to specify "chest X-ray to evaluate NG tube placement" to ensure an appropriate field of view. The X-ray should be obtained after initial insertion and before the tube is used for medication administration, feeding, or suction to prevent complications such as aspiration pneumonia or pneumothorax from improper placement. Key aspects to look for on the radiograph include the tube passing through the esophagus and into the stomach, with the tip ideally positioned in the body of the stomach below the gastroesophageal junction.
Some considerations when interpreting the radiograph include:
- The course of the NG tube should be carefully traced to ensure it does not deviate into the lungs or other inappropriate positions.
- The presence of any complications such as pneumothorax should be assessed.
- The position of the NG tube tip in relation to the gastroesophageal junction should be confirmed to be below this landmark, indicating proper placement in the stomach.
While other methods like auscultation or pH testing of aspirate are sometimes used, they are not as reliable as radiographic confirmation, which remains the gold standard for verifying correct NG tube placement, as emphasized by the American College of Radiology's appropriateness criteria for intensive care unit patients 1. In critical situations, portable X-ray equipment can be used at the bedside to minimize patient transport and expedite confirmation of proper placement.
From the Research
X-ray Evaluation for NG Tube Placement
To evaluate the placement of a nasogastric (NG) tube, a chest X-ray is commonly ordered. The following points highlight the importance and accuracy of X-rays in verifying NG tube placement:
- X-rays are considered the reference standard for verifying NG tube placement 2, 3, 4.
- A study found that 10% of NG tubes were malpositioned, with 2.2% being in the lung, and X-ray was the only method that detected these complications 2.
- Another study reported that X-ray checks detected a high percentage of unsafe tube placements, leading to repeated X-rays and delayed delivery of drugs and nutrition 5.
- The sensitivity and specificity of X-rays in verifying NG tube placement are high, with one study reporting that 85% of tubes were confirmed to be in the stomach, and 21% were in the oesophagus 4.
Alternative Methods for Verifying NG Tube Placement
While X-rays are the gold standard, other methods have been explored to verify NG tube placement:
- Colorimetric capnography has been shown to be a valid method for verifying NG tube placement, with a sensitivity of 100% and specificity of 99-100% 3.
- Capnography has also been found to detect NG tube position with high accuracy, but further research is needed to confirm its effectiveness 3.
- Other methods, such as aspiration of gastric fluid and pH measurement, have been found to be less sensitive and specific than X-rays 2.
Best Practices for Ongoing Verification of NG Tube Placement
To ensure patient safety, ongoing verification of NG tube placement is crucial:
- Best practices include marking the tube with inedible ink or adhesive tape at the time of radiographic confirmation, checking tube location at 4-hour intervals, and verifying placement/patency in patients who complain of pain, vomiting, or coughing 6.
- Adherence to these evidence-based strategies promotes patient safety and reduces the risk of complications associated with misplaced NG tubes 6.