Enteral Tube Placement Enteral tube placement is a common nursing intervention utilized to provide nutrition, administer medications, and decompress the stomach or intestines in patients unable to consume food orally. The process, while generally safe, carries risks and requires careful assessment, technique, and monitoring to ensure the patient’s safety and well-being. This paper discusses various aspects of enteral tube placement, including statistical data on tube insertion, potential errors, methods to confirm placement, and the nursing responsibilities involved in the procedure.
Enteral Tube Placement
Definition and Purpose
An enteral tube is a small-bore tube that can be inserted through the nose (nasogastric) or mouth (orogastric) and advanced into the stomach or small intestine. This intervention is primarily used for:
- Decompression: Relieving pressure caused by gas or fluid accumulation.
- Medication Administration: Delivering drugs directly to the stomach or intestines.
- Nutritional Support: Providing enteral nutrition when oral intake is not possible.
Indications for Use
Enteral tubes are indicated for patients with conditions such as:
- Neurological Disorders: Conditions that impair swallowing, such as stroke or traumatic brain injury.
- Obstruction: Tumors or strictures in the gastrointestinal tract that prevent normal swallowing.
- Postoperative Recovery: Patients who are unable to eat post-surgery due to anesthesia or surgical intervention.
Prevalence and Statistics
It is estimated that approximately one million enteral tubes are placed annually in the United States. Feeding through nasogastric (NG), orogastric (OG), or non-intentional (NI) tubes is preferred when the gastrointestinal (GI) system is functional, particularly for short-term nutritional support. The benefits of enteral feeding include:
- Achieving a positive nitrogen balance sooner than parenteral nutrition.
- Enhancing gut healing and function.
- Reducing the risk of bacterial translocation and infections.
Tube Insertion and Associated Errors
Error Rates in Tube Placement
Research has indicated that errors in the placement of enteral tubes are common. In adults, the prevalence of errors ranges from 1.3% to 89.5%, depending on the definitions used in the studies (McWey et al., 1988; Niv & Abu Avid, 1988). In children, studies show that 20.9% to 43.5% of enteral tubes are placed incorrectly (Ellert & Beckstrand, 1999; Ellett et al., 1998). These errors can lead to serious complications, emphasizing the need for careful insertion techniques and validation methods.
Types of Errors in Tube Placement
Errors in the placement of NG/OG feeding tubes can lead to significant complications, such as:
- Pulmonary Aspiration: If a tube enters the airway, feeding can result in aspiration pneumonia or other pulmonary complications.
- Malabsorption: Incorrect placement in the duodenum may lead to malabsorption, inadequate weight gain, or dumping syndrome.
- Tracheal Trauma: Insertion errors can cause damage to the trachea or surrounding tissues, leading to long-term complications.
Insertion Length Estimation
Techniques for Estimation
Accurate estimation of tube insertion length is crucial for ensuring correct placement. The traditional method uses the direct nose-ear-xiphoid (NEX) measurement, which has been found to be inaccurate in some studies (Hanson, 1979). Alternative methods include:
- NEMU Measurement: This involves measuring the distance from the nose to the earlobe and then to a point between the xiphoid process and the umbilicus, but studies have shown inconsistencies in accuracy.
- Height-Based Methods: Research suggests that using regression on height can be a more accurate predictor of the required insertion length in children (Beckstrand et al., 1990).
Challenges in Measurement
Despite the available methods for estimating insertion length, inconsistencies remain. For example, a survey revealed that 98% of nurses continued to use the NEX method despite evidence supporting alternative techniques (Shiao & DiFiore, 1996). This indicates a need for ongoing education and training to enhance nursing practices in tube placement.
Radiography and Tube Insertion
Verification Methods
Currently, abdominal radiography is the only consistently valid method for verifying the position of flexible small-bore NG/OG tubes. While radiographs can confirm tube placement, the cumulative radiation risk from multiple exposures and associated costs necessitate the development of bedside verification methods.
Limitations of Radiography
Although effective, radiography has limitations:
- Cost and Accessibility: Regular imaging can be costly and may not always be available in a timely manner.
- Radiation Exposure: Frequent radiographs increase the patient’s exposure to radiation, raising concerns about long-term effects.
Methods to Detect Errors in Insertion
Techniques for Detection
Several methods have been researched to detect errors in tube placement, including:
- Aspiration and pH Testing: Aspirating gastric contents and measuring pH can help determine the correct placement of the tube.
- Water Immersion: Placing the proximal end of the tube under water can indicate proper placement through bubbles observed during exhalation.
- Auscultation: Listening for gurgling sounds over the abdomen can suggest correct placement; however, this method is less reliable.
Efficacy of Detection Methods
Each detection method has its challenges:
- pH Testing: While pH testing can help differentiate between gastric and respiratory placements, it is not foolproof due to overlap in pH values and the effects of medications on gastric acidity (Metheny et al., 1999).
- Visual Characteristics: Examining the appearance of aspirates can assist in placement verification but may not be reliable enough alone (Metheny et al., 1994).
Fluids Aspiration and Composition
Differences in Fluid Composition
Aspirated fluids from different organs have varying pH levels. Metheny et al. (1999) found that gastric aspirates generally have lower pH values compared to intestinal aspirates. Understanding these differences can aid in determining tube placement, but variability in pH due to medications or conditions can complicate this process.
Limitations of Aspiration Methods
The aspiration of fluid may not always yield a sample, especially if the tube is improperly placed. Flexible small-bore tubes can collapse under suction, making it difficult to obtain aspirates. Furthermore, the administration of acid-inhibiting medications may affect pH readings, complicating the assessment of placement.
Recommendations for Practice
To improve accuracy in tube placement verification, Metheny and Stewart (2000) recommend measuring both bilirubin levels and pH of aspirates. This dual approach may provide a more reliable indication of correct placement compared to pH testing alone.
Key Points
- Prevalence of Errors: Errors in enteral tube placement are common and can lead to significant complications, highlighting the need for effective training and assessment methods.
- Insertion Length Techniques: Current techniques for estimating insertion length, such as NEX, NEMU, and height-based methods, have shown variable accuracy. Continuous education on optimal practices is essential.
- Verification Methods: Abdominal radiography is the most reliable method for confirming tube placement, but alternatives must be developed to reduce radiation exposure and costs.
- Detection Methods: The effectiveness of various detection methods, including aspiration and pH testing, varies, and no single method is completely reliable. A combination of techniques may yield better results.
- Fluid Aspiration: Understanding the composition of aspirated fluids can assist in verifying tube placement, but factors such as medication use and the method of aspiration may impact results.
Conclusion
Nursing considerations while placing enteral tubes are critical to ensuring patient safety and the effectiveness of the procedure. Ongoing research and education are necessary to address the challenges associated with enteral tube placement, verification, and complication management. By implementing evidence-based practices and refining techniques, nursing professionals can improve patient outcomes and minimize the risks associated with enteral feeding.