Providing patients with adequate nutrition is a prime responsibility of the bedside nurse. Most commonly, a temporary feeding tube is inserted nasally or orally in a patient who is unable to eat but has a critical need for nutrition.
Experts recommend feeding start as soon as possible after the need is identified. But initiating this access can present a challenge for caregivers, who may be focusing on more urgent clinical priorities during this critical period. Also, a busy nurse who inserts feeding tubes frequently may think she has the procedure down pat, but may not be up-to-date on evidence-based practice or use adequate caution to avoid potential complications, such as epistaxis and inadvertent tracheal placement.
Both authors have expertise in placing all types of nasogastric (NG) and orogastric (OG) tubes, with a primary focus on postpyloric placement of Dobhoff-style small-bore feeding tubes (SBFTs). In this article, we discuss our procedure for inserting SBFTs—but the safety points we emphasize apply to all temporary feeding tubes. We also describe ways to improve assessment and help you position the tube in the desired location.
Selecting the right tube, insertion route, and delivery site
Commonly used feeding tubes include the PVC-plastic Salem sump tube (for gastric feeding only) and the softer SBFT with a weighted or unweighted tip; both types come in various sizes. Entering the GI tract via the pharynx and esophagus, these tubes are used for temporary access to administer fluids, nutritional supplements, and medications. Facility guidelines or protocols typically determine the choice of tube (larger plastic or SBFT), insertion route (nasal or oral), and nutrition delivery site (gastric or postpyloric). In this article, we don’t discuss other devices meant for longer-term support that are placed via the percutaneous abdominal route.
To determine which type of enteral access is most appropriate, consider both the patient’s current situation and the likely progression of care. If a plastic NG or OG tube is already in place for gastric decompression, it can also be used for feeding at the appropriate time. When placing a new tube for nutrition, we prefer the SBFT for its greater comfort and features. SBFTs come in 8, 10, and 12 Fr sizes. The smaller sizes may be slightly more comfortable but are more likely to become clogged with formula, supplements, or medication fragments.
If you expect your patient to remain intubated and sedated or comatose for some time, the oral insertion route usually is preferable. It minimizes the risk of sinusitis linked to nasal placement; also, in many cases, an oral tube is removed with airway extubation or replaced at some point with a percutaneous endoscopic gastrostomy tube for long-term access.
But if you expect the patient to be awake and free of other oral tubes while still needing feeding access, a nasally inserted SBFT is more comfortable and better tolerated and allows the patient to eat or speak without the irritation of an oral tube.
Always consider safety when choosing the insertion route. Select an oral tube, for instance, for a patient with facial fractures. A nasal tube is more appropriate for a combative or agitated patient (especially one who’s not intubated) because it carries a lower risk of choking or gagging than an oral tube.
Practical considerations also should guide your choice of gastric vs. postpyloric nutrition delivery site. Usually, patients with adequate bowel motility and intact cough and gag reflexes who can have the head of the bed elevated at least 30 degrees at all times are good candidates for gastric feeding.
In contrast, postpyloric feedings may be more beneficial for patients who:
- can’t tolerate gastric feedings, as demonstrated by high gastric residual volumes
- must be kept flat in bed (due to traumatic injury or hemodynamic instability) or are expected to be immobile for a prolonged period
- have impaired GI motility or increased intra-abdominal pressure
- require ongoing gastric decompression (with an NG or OG tube)
- have respiratory failure requiring high levels of positive-pressure ventilation.
Postpyloric delivery promotes minimal residual volumes and better feeding tolerance and allows earlier progression to the feeding goal rate. Studies show it results in higher caloric and protein intake, presumably by not increasing gastric residual volume. Be aware, though, that an SBFT placed beyond the pylorus doesn’t prevent aspiration because the patient can still vomit gastric contents.
Pre-insertion safety steps
To minimize the risk of complications from feeding-tube insertion, take these steps before starting:
- Review the patient’s medical history, laboratory data, and medications.
- Assess mental status and ability to cooperate. A patient who is awake can assist with correct nasal or oral tube placement by tucking the chin and swallowing on command. If you think your patient won’t cooperate, sedation may be needed.
- Provide patient teaching.
Measuring for correct tube length
All enteral tubes have external markings to help identify tube position during insertion. On SBFTs and newer Salem sump tubes, these marks are usually in centimeters (cm).
Use standard landmarks when measuring. Place the distal tip of the feeding tube at the patient’s lip or nares, and use the tube to measure the distance back to one earlobe and then down to the tip of the xyphoid process; place a mark at this point to indicate the tube position at the lip or nares that correlates with placement of the tube’s distal tip in the stomach. This technique works for all types of temporary feeding tubes.
Starting the procedure safely
With any type of feeding tube, you may meet resistance when inserting the first 10 cm of the tube into the nasal passage. If you still can’t advance it by using gentle pressure and changing the approach angle, withdraw it and try inserting it through the other nostril. Never try to force passage of the tube.
Next, advance the tube past the oronasopharynx—usually to about the 20-cm mark at the nares or about 15 cm orally for an adult. Keep in mind that the oral route is shorter than the nasal route to the same anatomic landmarks. Stay especially alert for signs of airway placement during the 20-cm to 30-cm transit.
Insufflating air to promote tube advancement
When inserting an SBFT with postpyloric delivery as the goal, we recommend the proven air insufflation technique described here to help advance the tube safely from the gastric to postpyloric position. This simple technique requires minimal equipment and, with practice, significantly improves the chance of successful small-bowel placement. Used in conjunction with a carbon dioxide (CO2) detector, it offers safety and efficacy equal to that achieved with any reported insertion method.
Once the tube has been advanced to the 60-cm mark (stomach), aspirate and attempt to remove all air or gastric secretions. Then inject an air bubble (usually 300 to 400 cc) into the stomach to distend it and outline the greater (inferior) curvature for the SBFT to follow toward the pylorus. Advancing the tube 1 to 2 cm at a time allows the tip to move as the tube advances. If you meet resistance, stop to let the tip progress through the stomach folds or migrate with any peristalsis elicited.
Confirming tube placement clinically
To help evaluate for SBFT placement past the pylorus, auscultate injected air by location (abdominal quadrant); then test for ability to aspirate air or fluid and assess any secretions for color and character. On auscultation, air injected beyond the pylorus sounds higher-pitched and flatter than the lower-pitched, tympanic sound elicited in the stomach. Little to no return of air or fluid on aspiration may indicate small-bowel placement—or may simply mean the tip or holes of the SBFT (or other type of tube) are in the stomach but not reaching the gastric contents. Fluid return that resembles pure bile (a clear golden fluid) almost always signals postpyloric placement.
Clinical assessment of either gastric or postpyloric tube placement isn’t definitive, so tube feedings mustn’t begin until X-rays verify that the tube is in the desired position. In most patient settings, the gold standard for confirming correct tube position is the abdominal X-ray, which should be interpreted by a qualified physician or radiologist. In both the literature and our facility’s experience, an alarming number of “feeding the lung” cases have occurred when X-ray confirmation was omitted. If the initial X-ray leaves postpyloric placement in doubt, our radiologists suggest a repeat abdominal film with water-soluble contrast to clarify the location of the tube’s distal tip.
Securing the tube
Once correct tube position is confirmed, place an indelible mark on the tube at the lip or nares. This provides a quick visual reference to indicate safe tube position; it also alerts caregivers if the tube becomes displaced. Put feedings on hold until you reconfirm proper tube position by clinical assessment, repeat X-ray, or both.
Many taping methods and products can be used to secure the tube. Whichever you use, be sure to apply them properly and to change the tape regularly to keep the tube properly anchored.
Some patients may need physical restraint, sedation, or both to reduce the risk of pulling out the feeding tube. We’ve had success using a new form of nasal bridle to secure the tube, reducing the need to restrain the patient. This simple magnetic device, inserted via both nares, is easy to apply and largely eliminates inadvertent tube dislodgment by the patient or staff.
Careful technique promotes positive outcomes
The low-cost bedside practices we’ve described can benefit patients by helping to ensure safe feeding-tube placement and promoting an early start to enteral nutrition. Some healthcare facilities are training selected clinicians to become experts in feeding-tube insertion, but any nurse can learn and effectively use our methods. Most importantly, we strongly recommend you use some type of CO2 detection to help prevent tube placement in the lung.
American Association of Critical-Care Nurses Practice Alert: Verification of feeding tube placement. Available at: www.aacn.org/AACN/aacnnews.nsf/GetArticle/ArticleThree225. Accessed June 26, 2007.
Burns S, Carpenter R, Blevins C, Bragg S, Marshall M, Browne L, et al. Detection of inadvertent airway intubation during gastric tube insertion: capnography versus a colorimetric carbon dioxide detector. AJCC. 2006;15:188-195.
Lenart S, Polissar N. Comparison of 2 methods for postpyloric placement of enteral feeding tubes. AJCC. 2003;12(4):357-360.
For a complete list of selected references, visit www.AmericanNurseToday.com.
Paul Merrel, MSN, RN, is an Advanced Practice Nurse 1 (APN 1) and Outcomes Manager for the Surgical/Trauma/Burn ICU and Neurosciences ICU at the University of Virginia Health System in Charlottesville. Charles Fisher, MSN, RN, CCRN, ACNP-BC, is an APN 1 and Outcomes Manager for the Medical ICU, Coronary Care Unit, and Thoracic/Cardiovascular Postoperative Unit at the same facility.