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Note to our readers: Annals of Long-Term Care has published more recent content on this topic. Please check out the following articles for more up-to-date information on tube feeding:
- When Evidence Clashes With Emotion: Feeding Tubes in Advanced Dementia
- Tube Feeding Versus Assisted Oral Feeding for Persons With Dementia: Using Evidence to Support Decision-Making
- End-of-Life Nutrition: Is Tube Feeding the Solution?
- AGS Supports Evidence-Based, Patient-Centered Use of Feeding Tubes in Advanced Dementia
In long-term care (LTC) residents with impaired caloric or fluid intake and a functional gastrointestinal tract, enteral nutrition through the use of a feeding tube is an important option.1-4 Year 2006 Minimum Data Set (MDS) data from New York State revealed that 8.1% of all nursing home residents were receiving tube feedings. State-to-state rates varied widely, with Nebraska having the lowest rate of 3.8% and the District of Columbia having the highest rate of 44.8%. Enteral nutrition may be provided to patients utilizing nasoenteral, gastrostomy, and jejunal feeding tubes.3 These tubes are easy to insert and suitable for short- and long-term use. However, feeding tubes are associated with various complications that require close monitoring.5,6
Feeding Tube Types
Nasoenteral feeding includes nasogastric, nasoduodenal, and nasojejunal tubes.1 Most common are the nasogastric tubes.3 They may be used in patients with competent lower esophageal sphincter, lack of involvement of the stomach by the primary disease process, and normal gastric emptying. The large reservoir capacity of the stomach is an advantage for their use. Nasoduodenal and nasojejunal tubes may be used in patients who cannot tolerate gastric feedings or who need to lie flat, (ie, ileus, critically ill patients).3 Gastrostomy tubes are used when a patient cannot or will not eat for a prolonged time course (longer than 4 wk) and has a functional gut.7 Gastrostomy tubes are generally placed in the procedure commonly known as percutaneous endoscopic gastrostomy (PEG).7 Gastrostomy tubes may also be placed surgically, and more recently via a computed tomography–guided procedure.4 In the year 2000, more than 216,000 gastrostomy tubes were placed in the United States alone.7 Jejunostomy is indicated for patients who need long-term enteral nutrition and have chronic aspiration, gastric outlet obstruction, or stomach or duodenal disease, or for patients with prior gastrectomy.2-4 Jejunal feedings may be achieved using direct endoscopic techniques or with jejunal extension of a feeding tube through an existing PEG.
Feeding Tube Complications
Aspiration. Aspiration is one of the most important and controversial complications in patients receiving enteral nutrition, and is among the leading causes of death in tube-fed patients due to aspiration pneumonia.7-10 However, differentiation of aspiration from oropharyngeal or gastric contents is difficult to assess.11 The rate of aspiration pneumonia in tube-fed patients ranges from approximately 5% to 58%.7-9 Aspiration often occurs without obvious evidence of vomiting or regurgitation and is recognized by the development of clinical signs of respiratory compromise or pneumonia.9-10Nasoenteral and gastrostomy tubes are used by some to prevent aspiration, although evidence is lacking to support this belief.9Additional risk factors for the development of aspiration pneumonia include advanced age, the presence of esophagitis on endoscopy, gastroesophageal reflux, prior history of aspiration or pneumonia, impaired level of consciousness, neurologic deficits, poor oral hygiene, and sedative medications.10Treatment includes stopping the feed, attempts at aspirating the feed from the lungs, and antibiotics if signs of infection are evident. Feeding beyond the duodenum likely lowers the incidence of aspiration, although no conclusive evidence supports this premise.9,10
The goal in the LTC setting is to use preventive measures to decrease the incidence of aspiration and its development into pneumonia by targeting modifiable risk factors. To minimize the risk of aspiration, patients should be fed sitting up or at a 30- to 45-degree semirecumbent body position.8,11 They should remain in the position at least one hour after feeding is completed. Iso-osmotic feeds may be preferred since high-osmolality feeds can delay gastric emptying. Intermittent feeding (200-400 mL every 4 hr) is preferred for gastric feedings due to reservoir of stomach; in contrast, continuous feeding (20-40 mL/hr) is standard for jejunal feeding. However, the effect of feeding type on risk of aspiration is inconsistent.8,11 Since there may be an increased risk of aspiration if gastric contents accumulate, the gastric residual volume (RV) should be checked. There is no standard definition as to what constitutes a safe RV. While the general practice is to hold feeding for RV of > 200 mL, recent experts recommend increasing the amount that constitutes a significant RV to 400-500 mL.5,9 If the RV is set too low, patients often do not reach their nutritional goal because of feeds being held. For continuous feedings, residual can be checked while the infusion is in progress; for intermittent feedings it is checked one hour after cessation of feeding.8,9
Although acid suppression may help with symptoms of reflux, it does not prevent aspiration pneumonia. Promotility drugs may reduce the risk of aspiration in patients at risk. Another modifiable risk factor is dental hygiene. One study looking at oral care in nursing home residents demonstrated that aggressive oral care lowered the risk of pneumonia.11
Diarrhea. The most common reported complication of tube feeding is diarrhea, defined as stool weight > 200 mL per 24 hours.2-5 However, while enteral feeds are often blamed for the diarrhea, it has yet to be causally linked to the development of diarrhea. When a patient develops diarrhea, the clinician should begin by checking for changes in infusion rate or change in formula.2-5 Other common causes are medications, infection, bacterial contamination, and impaction.2-5 Often, patients are on standing doses of laxatives, which need to be held. Many liquid medications contain sorbitol and can induce diarrhea by increasing the osmotic load to the intestines. Other common offenders are medications containing magnesium, nonsteroidal anti-inflammatory drugs, H2 blockers, proton pump inhibitors, and antibiotics. Reduced gastric acid caused by H2 blockers and proton pump inhibitors may lead to small intestinal bacterial overgrowth. Antibiotics seem to induce diarrhea more frequently in enterally-fed patients than normally-fed ones.2-5 Diarrhea often coincides with the initiation of enteral feeding since many of the medications that were previously given by intravenous routes are now converted to enteral route at the same time of feeding initiation. Enteral feeds are an ideal culture medium and can become contaminated with bacteria during handling or if allowed to stand in a feeding bag for more than 12 hours.2-5 Therefore, careful handwashing can minimize contamination, and feeding bags and tubing should be changed daily. Opened formulas should be refrigerated. In addition to gastrointestinal problems, sepsis can occur.
Management of diarrhea is directed at the underlying cause; however, several therapeutic strategies are available in the absence of an obvious etiology. Decreasing the feeding flow rate may alleviate diarrhea by allowing time for intestinal mucosal adaptation to occur when the gastrointestinal tract has not been used for extended periods of time. The flow rate is then increased gradually over the next several days. Supplementation of formulas with fiber or switching to a fiber-enriched feed has not resulted in consistent results but may be attempted.12 Stool samples should be tested for Clostridium difficile (C. difficile) toxin.13 C. difficile is found in 20-50% of patients with antibiotic-related diarrhea. If lactose intolerance is suspected, switch to a lactose-free formula. Consider obtaining a fecal fat test for malabsorption if diarrhea persists. However, the concept that diarrhea relates to malabsorption is not well supported due to the efficiency of the gatrointestinal tract. A change to an elemental or predigested feeding formula is rarely needed unless significant impairment in gastrointestinal function and absorption is well documented. Additionally, isotonic formulas are well tolerated when started at full strength. However, hypertonic formulas such as calorically dense 2 calories per mL and elemental formulas are best initiated at half strength and changed to full strength 24 hours later. Importantly, patients should be also examined for fecal impaction.
Nausea, vomiting, or abdominal bloating. Nausea may be due to smell, abdominal bloating, and cramps. Abdominal bloating and cramps are often be due to excess feed administration rates, delayed gastric emptying, or decreased bowel motility that often present in frail elderly.2-5 Mobilization of the patient does not invariably improve bowel function. Importantly, clinical evidence of abdominal distention is a contraindication to enteral feeding. Nasoenteric tubes are associated with more reflux.
Management includes assessment for abdominal distention and fecal impaction. If a patient is receiving intermittent feeds, then the feedings can be changed to a slower rate of continuous feeds. Switching to a more calorie-dense product may also decrease the total volume and rate infused. If the residual volumes are elevated, a prokinetic agent such as metoclopramide or erythromycin may be tried.
Metabolic and electrolyte imbalances are common complications associated with enteral feedings.13 Specific imbalances are related to either high or low serum levels of sodium, potassium, phosphorus, magnesium, zinc, copper, vitamins, trace elements, and water.14
Fluid management must be carefully monitored in patients receiving enteral feeding to avoid electrolyte imbalances and fluid balance alteration.13,14 Excess free-water leading to overhydration and hyponatremia may occur in up to 25% of patients receiving enteral feeding. This may occur when a patient is receiving IV fluids or high volumes of free-water boluses. Slowing the infusion rate or substitution of a 1.5 to 2 kcal/mL formula may be used. Hypernatremia is seen in at least 10% of cases secondary to iatrogenic causes such as free-water restriction for medical reasons, free-water loss, feeding of calorie-dense formulas, and excessive use of normal saline by intravenous infusion concomitantly.
Hyperglycemia is also very common (10-30%) in patients being fed enterally. High calorie intake may unmask glucose intolerance or diabetes. Acute illness, overfeeding, in addition to inappropriately low insulin or medication supplementation can account for hyperglycemia.13,14
The refeeding syndrome is a potentially fatal complication seen when severely malnourished patients are refed via enteral or parenteral support.15 It usually occurs with rapid replacement of large amounts of nutrients. Those at risk for this syndrome include individuals who are chronically malnourished, chronic alcoholics, anorectics, and those chronically ill and receiving IV fluids without nutrients for 7-10 days.15,16 When malnourished patients are refed it creates an increase in metabolism leading to a shift of fluid and electrolytes. This is often accompanied by alteration in levels of sodium, potassium, magnesium, phosphorous, and thiamine. Hypophosphatemia is thought to account for most symptoms of the refeeding syndrome. The syndrome can cause cardiac, respiratory, neuromuscular, gastrointestinal, and renal complications (Table I). To avoid this syndrome one must estimate a patient’s nutritional needs, and then initiate feeding slowly and carefully follow serum electrolyte and mineral levels. Thiamine deficiency may contribute to refeeding syndrome with Wernicke’s encephalopathy precipitated by carbohydrate administration.13-16
Feeding tubes are associated with many mechanical complications (Table II). The insertion of a nasoenteral tube may cause discomfort, rhinitis, esophageal reflux and strictures, esophagitis, perforation of a pharyngeal or esophageal pouch, intracranial insertion, and accidental bronchial insertion and perforation.2-4 Intracranial insertion is a small but documented risk. This risk is minimized by the use of flexible polyurethane or silicone tubes; however, modern tubes with internal wires increase this risk. Reinsertion of guidewires with feeding tubes in situ should not be attempted due to the risk of wire passing either through an outflow port or perforating the tube, and then perforating the viscus.
The position of the nasoenteral feeding tube should be confirmed radiologically before initiating feeding since checking the position of a tube by aspiration of gastric contents or injection with air through it and listening for bubbles with a stethoscope is unreliable.2-5 Approximately 25% of nasogastric tubes fall out or are pulled out inadvertently. Nasoenteral tubes should be secured with tape, and the distance the tubes are inserted should be recorded—or even the tube itself marked with tape—so migration can be identified. The length should be checked every 4 hours during tube feeding. It should also be checked every time it is used by confirming that the external length of the tube remains unchanged. Post-insertion nasoenteral tubes are associated with discomfort, sore mouths, thirst, dry mucous membranes, and hoarseness.2,3 These symptoms may be remedied by mouthwashes and artificial saliva. Local pressure of nasoenteral tubes may cause nasal erosions, abscess formation, sinusitis, and otitis media. Esophageal complications can include esophagitis, ulceration, strictures, tracheal fistulas (especially in presence of endotracheal tube), and exacerbation of variceal bleed. These complications can be minimized by the use of fine bore tubes. Tube feeding may also be associated with higher rates of restraints and pressure sores.2-5
Accidental removal of the gastrostomy tube within the first four weeks of placement can be problematic since a formed tract is not established, and the stomach wall may not yet have adhered to the abdominal wall.6,7 A water-soluble contrast study should be done to evaluate for any extravasation of gastric contents, and a new tube should only be inserted endoscopically. A replaceable feeding tube or a Foley catheter should not be placed after accidental removal of a recently placed gastrostomy tube (< 4 wk).16-19 Tube dislodgement after four weeks should be re-inserted without delay, since even established tracks can narrow or close within hours. A Foley catheter can be inserted through the tract and feeding restarted until the gastrostomy is replaced either endoscopically or non-endoscopically with a replaceable gastrostomy tube. After non-endoscopic re-insertion, tube position should be verified by a combination of auscultation and aspiration of gastric contents. If unable to confirm by a combination of both auscultation and aspiration of gastric contents, or if any resistance during insertion, confirmation of tube placement should be performed by injection of water-soluble contrast (Gastrografin®), followed by a plain x-ray or direct endoscopic visualization. Unintentional dislodgement can be minimized by checking that the balloon volume is adequate every seven days.
A common complication of gastrostomy tubes is leakage.7 Tube leakage can cause severe skin excoriation and major hygiene problems. A larger replacement tube may help. Lowering the acidity of the gastric contents by the use of H2 blockers or proton pump inhibitors will decrease skin excoriation and may decrease gastric secretions. Additionally, aluminum hydroxide and magnesium hydroxide antacid can be applied around the stoma twice daily. Weight changes (+/- 10 lb) can alter the tension on the bumper and can cause leakage. This can be prevented by adjusting the bumper if weight loss occurs.
Feeding tubes can commonly become blocked, especially if they are not flushed with at least 30-60 mL of water every feeding or medication administration. Bolus feeding, hypertonic, high-fiber formulas, crushed tablets, potassium, iron supplements, and sucralfate are particularly likely to cause blockage.2-7 Whenever possible, elixir forms of medications should be used. The tube should be flushed every 4-6 hours during continuous feeds and after every medication dose and bolus feeding.2-7 A tube may be unblocked by flushing with warm water or cranberry juice. The use of solutions with pancreatic enzymes or meat tenderizer should be done with caution, as this may harm the gastric mucosa or the tube. Carbonated drinks, pineapple juice, and sodium bicarbonate solution may cause tube degradation. Gastrostomy tubes may also be blocked by gastric mucosal overgrowth, which requires endoscopic repair.7 Tube blockage or intraperitoneal leakage can be assessed using water-soluble contrast. Buried bumper syndrome is an unusual late complication of gastrostomy tubes due to migration of the internal bumper through or into the abdominal wall.20,21 Failure to recognize this syndrome may result in serious complications, including gastrointestinal bleed, perforation of the stomach, peritonitis, and death.22,23
Drug-Enteral Feeding Complications
Medications are frequently prescribed for patients dependent on enteral tube feeding. Failure to recognize these interactions may lead to treatment failure, toxicity, and life-threatening adverse events. Such interactions often involve drugs with a narrow therapeutic index, drugs that interact with food or electrolytes, or when multiple drugs in liquid form are given concomitantly with enteral feeds.24-27 Many interactions can be avoided by withholding enteral feedings for two hours before and after the administration of medications (Table III).24-27
Feeding tubes are commonly used in the LTC setting. Their use may be associated with complications such as aspiration, diarrhea, nausea, abdominal bloating, and metabolic or mechanical problems. A systematic and careful analysis of the underlying cause of these complications is critical to a successful enteral nutrition program.
The authors report no relevant financial relationships.
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