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THE AMERICAN SOCIETY for Parenteral and Enteral Nutrition (A.S.P.E.N.) routinely publishes recommendations based on current evidence-based literature, a consensus of expert opinions, and knowledge of best practices related to the safe ordering, delivery, and monitoring of both parenteral and enteral nutrition (EN). This article discusses the latest EN practice recommendations issued in 2009, with an emphasis on specific nursing applications and patient safety.1 Keep in mind that these recommendations should be used in addition to expert judgment by the health professionals managing the patient's care.
By definition, EN is nutrition provided through the gastrointestinal (GI) tract distal to the oral cavity via a tube, catheter, or stoma.1 Orders for EN should be written completely and specifically for each patient in readily understandable terms, avoiding the use of dangerous abbreviations or inappropriate numerical expressions. Patient-specific EN orders should include:
* patient demographics, including name, date of birth, weight, room number, and medical record number.
* the formula, identified by either the generic or specific trade product name, and the strength of the formula, if diluted.
* the enteral access route (gastric or postpyloric) and access (such as nasogastric [NG] or nasoduodenal).
* the administration method (pump-assisted, gravity-assisted, or bolus) and rate of administration.1
All bottles, bags, and syringes used in syringe pumps should have a label with the following information: patient demographics, formula type, enteral access delivery site/access, administration method, name/initials of those -preparing and hanging the product, the date and time that the formula was prepared and hung, and an expiration date or beyond-use date. Always confirm that the correct -formula is being given to the patient by comparing the label to the order.
The words "Not for I.V. Use" should be on the same or separate label to help prevent enteral misconnection errors. In addition, check the manufacturer's expiration date on the enteral formula administration container.
The use of tap versus sterile water to reconstitute powdered enteral formulas, dilute medications, and provide water flushes has recently been clarified. Three types of water can be found in healthcare settings: purified water, tap water, and distilled water.
* Purified water is sterile water free from any chemical or microbial contaminants. It's the only type of water that should be used for critically ill and immunocompromised patients, as well as for anyone requiring postpyloric tube feedings. It's currently recommended that purified water (sterile water for injection) be used for formula reconstitution and for medication dilution. The guidelines also state that 0.9% sodium chloride solution can be used as the diluent or flushing solution in place of any other recommended fluid, including purified water.
* Tap water is the locally available water regulated by state and ational organizations. It's acceptable for the hydration of a healthy patient with no immunocompromise, but houldn't be used to dilute powdered formula or to dilute medications.
* Distilled water has been vaporized and recondensed, but may still contain harmful substances, so it hould not be used in healthcare settings.
The contamination of tube-feeding formulas can occur at multiple points during the preparation and administration process. Healthcare-associated infections increase significantly when basic hygiene measures aren't taken. Isolates that have been found in contaminated EN formulas include Gram-negative bacilli, Gram-positive organisms, anaerobes, and yeast.1
When diluting powdered formulas, take special care to use strict sterile technique to avoid inadvertently introducing pathogens. The guidelines specify that EN formulas be prepared in a clean environment by specially trained personnel using sterile technique. Actions to prevent contamination include hand hygiene before preparing and administering EN, and preparing it away from any storage or trash areas. The guidelines also recommend the use of gloves to prepare and administer EN, and state that wearing a disposable mask, gown, gloves, and head cover may reduce the spread of airborne bacteria.
When accessing the enteral tube hub, perform hand hygiene and clean each tubing connection with an alcohol swab. Hand hygiene should also be performed between glove changes and when moving from a dirty procedure, such as gastric residual aspiration, to a clean procedure, such as handling the EN formula. Don't let any part of the delivery system come into contact with nondisinfected hands, skin, clothing, or other surfaces.
Unopened liquid commercially available EN formulas should be stored in a designated dark, dry, cool place, according to institutional protocol and manufacturer recommendations. Reconstituted formula that's not used should be immediately refrigerated and discarded within 24 hours if still not used. The guidelines state that sterile, liquid EN formulas should be used in preference to powdered, reconstituted formulas whenever possible because the risk of contamination is lower.
If available, an enteral administration set with a drip chamber is preferable to one with no drip chamber to prevent retrograde bacterial contamination of the formula during administration.
Under the guidelines, hang time is defined as the time an EN formula is considered safe for delivery to the patient, beginning from the time when the formula was reconstituted, warmed, or decanted, or from the time when the original package seal was broken. Your hospital should have a policy and procedure on the length of time EN formula can be infused once the bottle or can is opened or spiked. Powdered, reconstituted formula has a maximum hang time of 4 hours because powdered formulas aren't available in sterilized form. The hang time for open systems (cans of ready-to-use formula opened and exposed to the air) is 4 to 8 hours. Closed systems (a liter of formula accessed by a spike set) may hang for 24 to 48 hours per manufacturer guidelines.
Administration sets for open systems should be changed at least every 24 hours. Refer to the manufacturer guidelines or hospital policy and procedure for instructions on how often to change the administration set on a closed system.
Tubing with a recessed spike is preferable to an open spike set when available, due to the decreased risk of contamination.
Many factors should be taken into consideration when deciding on an enteral access device, including the patient's disease state, GI anatomy, GI function, estimated length of therapy the patient will need, and capability of the patient or caregiver. The primary healthcare provider selects the device, but familiarity with these devices and signs of possible misplacement are important nursing knowledge.
Devices inserted via the nose or mouth are intended for short-term use, usually no longer than 6 weeks. Always verify NG or orogastric tube placement after insertion and before each use.
Verification can be done several ways. An X-ray is the gold standard for confirming the correct position of a blindly inserted enteral tube. (Tubes inserted with the assistance of fluoroscopy or endoscopy aren't blindly inserted.) Confirming the position of a newly placed tube is mandatory before the tube is used.
Bedside checks for placement can be done by testing the pH of the aspirate. Fluid from the stomach is typically clear and colorless or grassy green and has a pH of 5 or less. However, gastric aspirate may not be reliable if a patient is taking a medication to suppress gastric acid, such as famotidine or pantoprazole. If the tube could possibly have migrated into the lungs, fluid looks pale yellow and has a pH of 7 or higher. Testing for pH should serve as a preliminary test and should not replace the gold standard, X-ray confirmation. Follow up any suspicious finding with an X-ray before instilling anything into the tube.
The auscultatory method isn't reliable. Case reports have indicated that differentiating among respiratory, esophageal, or gastric placement based on air auscultation is too -difficult.2,3
Always mark the exit site of the feeding tube at the time of the X-ray. If the length of the tube changes, the tube may have migrated out of correct position. As prescribed, obtain a repeat X-ray to determine tube location. Withhold administration of all formula and medications via the enteral access device until proper placement has been confirmed.
Long-term devices include percutaneous endoscopic gastrostomy (PEG), percutaneous endoscopic jejunostomy, and percutaneous endoscopic gastrojejunostomy tubes. These devices aren't usually placed if oral feedings are an option and the patient can potentially meet nutritional needs, the need for enteral feeding is expected to be less than 4 weeks, the placement risks outweigh the benefits, or the patient is near end of life.
Urinary drainage catheters or GI drainage tubes are not intended to be feeding devices and should never be used for EN because they don't have external anchoring devices and can migrate, causing obstruction or aspiration.
Enteral feedings should be started postoperatively in surgical patients without waiting for flatus or a bowel movement. Feedings may be started within 2 hours of the placement of a PEG tube in adults.
Tube feedings may be administered using bolus, intermittent, or continuous techniques, or a combination of these methods. Bolus feedings are delivered by gravity via a syringe over about 15 minutes. Intermittent feedings are delivered via feeding container or bag, with or without an enteral feeding pump, over 30 to 45 minutes.
In general, it's no longer necessary to dilute enteral formulas; full-strength formula is associated with better patient tolerance (such as less diarrhea) and less microbial contamination. Limited data are available on appropriate initial rates but stable patients generally tolerate rapid rate advancement, reaching the goal within 24 to 48 hours. Severely -malnourished patients may need a slower initial rate to goal to prevent the development of refeeding syndrome (discussed below).
Administer bolus feedings only when infusing formula into the stomach of patients with intact gag reflexes. Pump-assisted feedings are required for small-bowel feedings, and slower rates often improve tolerance. Currently, no maximum upper limit on tube feeding rates has been established; patient tolerance should be the clinician's guide.
When a patient is kept flat in bed, the risk of aspiration increases exponentially. A patient may also aspirate when the head of the bed (HOB) is less than 30 degrees. The current recommendation is that all patients receiving EN have the backrest elevated to a minimum of 30 degrees and preferably to 45 degrees unless medically contraindicated. If a patient can't tolerate back elevation, use the reverse Trendelenburg position. If the HOB must be lowered for a procedure, follow your facility's policy and procedure to stop the feeding until the HOB can be raised again. Be sure to return it to the elevated position as soon as possible.
Feeding tubes are prone to clogging (obstruction) for many reasons, including infrequent water flushes, mixing of tube feeding formula with gastric fluid during gastric residual checks, interaction between multiple medications and protein-rich formula, small-diameter tubes, and administration of nonwater solutions such as cola or juice. To maintain tube patency in adults, feeding tubes should be flushed with 30 mL of water every 4 hours during continuous feeding, or before and after intermittent feedings. In addition, the feeding tube should be flushed with 30 mL of water after each residual volume measurement, and with at least 15 mL of water before and after each medication administration via the EN device. As previously discussed, you can use tap water for these flushes unless the patient is immunocompromised or critically ill; for these patients, use sterile water.
Use only water to flush feeding tubes. Studies have found cranberry juice and carbonated beverages, which were commonly used in the past, to be inferior solutions.1
Preventing tube misconnections is essential for patient safety. If an enteral feeding system is inadvertently connected to a non-enteral system such as an I.V. catheter, peritoneal dialysis catheter, or tracheostomy tube, a patient can suffer serious harm and may die.
Multiple medical committees have convened since 1972 to address the safety requirements for enteral feeding set connectors and adaptors. Color-coding and/or labeling should always be used, but that doesn't entirely eliminate the risk. The only way to prevent enteral misconnections is to develop and use enteral equipment that is designed to be completely incompatible with all existing I.V. connections. Until this happens, it's up to clinical staff to be knowledgeable about the use of the devices, trace all lines back to their origin, and ensure that they're secure. Use only oral syringes, not luer-lock syringes, labeled "for oral use only," to draw up and administer medications into the feeding tube to help prevent inadvertent administration into a vascular access device.
One recommendation to improve safety is to place tubes and catheters with different purposes in differing standardized locations, such as hanging all I.V. equipment at the HOB and all enteric equipment at the foot of the bed. Instruct the patient, non-nursing staff, and visitors that only nurses should reconnect lines.
The administration of oral medications through an enteral feeding tube requires some special precautions. Factors to consider include the internal diameter and length of the tube, the routine flushing schedule, the location of the tube's distal end, and the need to separate the drug from the enteral feeding formula. Current practice recommendations are that medication should never be added directly to an enteral feeding formula and that medications should be administered individually, with flushes of at least 15 mL between each medication administration. Always use liquid dosage forms when available.
For adult patients, the following protocol is recommended:
* Before giving a medication, stop the feeding and flush the tube with at least 15 mL of water.
* Dilute the medication as indicated and administer it with a clean oral syringe at least 30 mL in size.
* Flush the tube again with at least 15 mL of water (taking the patient's volume status into consideration).
* Repeat this sequence for each subsequent medication.
* After administering all medications, flush the tube with at least 15 mL of water one last time.
Never crush time-released solid medications for enteral administration. However, immediate-release solid dosage forms may be ground into a fine powder and mixed with sterile water. Hard gelatin capsules may be opened and the powder mixed with sterile water for enteral administration.
Monitor fluid and electrolyte status before initiating enteral feedings and periodically during therapy, especially in patients with recent, unplanned weight loss of at least 10% body weight. When a starved body system is reintroduced to nutrition, potassium, magnesium, and phosphorous are driven into cells as a result of the rise in insulin, resulting in potentially life-threatening electrolyte imbalances. Signs and symptoms of refeeding syndrome include cardiac dysrhythmias, muscle weakness, nausea, vomiting, seizures, and fluid retention. (See How electrolyte levels change in refeeding syndrome.)
To prevent refeeding syndrome in at-risk patients, start tube feeding at a slow rate (10 to 15 mL/hour) and proceed to the goal rate over 3 to 5 days.4
All patients who receive enteral feedings into the stomach are at risk for aspiration and its complications, such as pneumonia and hypoxia. Check gastric residual volume (GRV) every 4 hours during the first 48 hours of gastric enteral feeding. Afterward, GRV checks can be decreased to every 6 to 8 hours in noncritically ill patients. Checks should continue every 4 hours if the patient is considered to be critically ill. Follow your facility's policy and procedure to determine when to decrease, hold, or stop enteral feeding.
Monitor the pattern of GRV carefully. Assess the patient for GI pain, abdominal distension, emesis, or constipation.
Current A.S.P.E.N. recommendations state that if GRV is 250 mL or more for two consecutive checks, clinicians should consider administration of a promotility agent such as metoclopramide. If GRV is more than 500 mL, stop the feeding and reassess the patient, including GI assessment. Evaluate glycemic control (hyperglycemia can affect gastric emptying), minimize sedation, and/or administer a promotility agent if prescribed. Notify the healthcare provider because such high residuals place the patient at a significant risk of aspiration. The healthcare provider may consider a medical intervention, such as placing a feeding tube in the small bowel, beyond the ligament of Treitz, to prevent reoccurrence of high residual levels.
The complex nature of EN administration necessitates careful measures to ensure patient safety and effective therapy. These measures include frequent patient assessment, attention to hand hygiene and sterile technique when indicated, proper patient positioning, and appropriate medication administration technique. Nutrition support involves a multidisciplinary approach to deliver safe, evidence-based care.
1. American Society for Parenteral and Enteral Nutrition. A.S.P.E.N. enteral nutrition practice recommendations. JPEN J Parenter Enteral Nutr. 2009;33(2):122-167. [Context Link]
2. Lewis SL, Dirksen SR, Heitkemper MM, Bucher L, Camera I. Medical-surgical Nursing: Assessment and Management of Clinical Problems. 8th ed. St. Louis, MO: Elsevier Mosby; 2011:932. [Context Link]
3. Potter PA, Perry AG. Fundamentals of Nursing. 7th ed. St. Louis, MO: Elsevier Mosby; 2009:1206-1207. [Context Link]
4. Yantis MA, Velander R. How to recognize and respond to refeeding syndrome. Nursing. 2008;38(5):34-39. [Context Link]
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