e-SPEN, the European e-Journal of Clinical Nutrition and Metabolism 4 (2009) e209–e211
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Educational Paper
Basics in clinical nutrition: Complications of enteral nutrition Gyorgy Bodoky a, Luiza Kent-Smith b a b
St. Laszlo Teaching Hospital, Budapest, Hungary University of Porto, Porto, Portugal
a r t i c l e i n f o Article history: Received 8 May 2009 Accepted 13 May 2009 Keywords: Diarrhoea Nausea Vomiting Constipation Aspiration
Learning objectives To know the basic types of complications connected with tube feeding To be able to prevent complications of enteral nutrition Enteral nutrition (EN), as a form of nutritional therapy, is intended to compensate or overcome the inability of patients to voluntarily ingest food. EN is a relatively safe procedure with limited complications that can usually be avoided or managed. Very often the complications arise from inadequate formula and/or delivery site and rate, as well as being the indirect result of the underlying disease or medical treatment. EN complications can be classified as primarily gastrointestinal, mechanical and metabolic, however, when they occur, the distinction may not be so clear cut, which renders the correct diagnosis of the aetiology a very important issue. 1. Gastrointestinal complications
appropriately used i.e. adequate formulation, taking into account the delivery site and patient adjusted rate of infusion. Nevertheless diarrhoea can occur in spite of these safeguards, and it has been shown repeatedly that antibiotics or pathogenic microflora are usually implicated. If clinically significant, the following issues should be addressed: - Review patient’s EN prescription; - Rule out constipation or stool incontinence independent of feeding. Exclude infectious diarrhoea through stool culture; - Review medication profile, searching for diarrhoea inducing drugs, in particular prolonged use of antibiotics; - Should diarrhoea persist, these options ought to be considered: Decrease delivery rate Change to EN formula with a source of soluble fibre If malabsorption is suspected, change to oligomeric or monomeric diets If, despite the above measures, the problem persists, parenteral nutrition should be considered.
1.1. Diarrhoea
1.2. Nausea and vomiting
Diarrhoea is perhaps the most common complication in EN, occurring within a wide range (2–63%), depending on how it is defined. Definitions vary from one liquid stool a day to over 500 ml of soft or liquid stools/day on two consecutive days. Diarrhoea is not an inherent complication of EN, it can be prevented if EN is
Approximately 20% of patients on EN experience nausea and vomiting. The last greatly increases the risk of aspiration pneumonia. Although multifactorial, delayed gastric emptying is the most common cause. Warning signs, in the conscious patient, include abdominal discomfort and/or a sense of bloating. If delayed gastric emptying is suspected, consider reducing sedating medication, switching to a low fat formula, reducing the rate of delivery and administering prokinetic drugs.
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G. Bodoky, L. Kent-Smith / e-SPEN, the European e-Journal of Clinical Nutrition and Metabolism 4 (2009) e209–e211
1.3. Constipation
Table 2 The most frequent metabolic complications of enteral nutrition.
Constipation can result from inactivity, decreased bowel motility, decreased water intake (calorie dense formulas), impaction, or lack of dietary fibre. Poor bowel motility and dehydration may cause impaction and abdominal distension. Constipation should be clearly differentiated from bowel obstruction. Adequate hydration and the use of insoluble fibre containing formulas usually resolve the problem. Persisting situations may require stool softeners or bowel stimulants.
Type
Cause
Solution
Hyponatraemia
Overhydration
Hypernatraemia Dehydration
Hypophosphataemia
Inadequate fluid intake Diarrhoea Inadequate fluid intake Excessive energy intake Insufficient insulin Refeeding syndrome Diarrhoea Excessive K intake Renal insufficiency Refeeding syndrome
Change formula Restrict fluids Increase free water Evaluate diarrhoea causes Increase free water intake Assess energy intake Adjust insulin dosage Adjust for K depletion Evaluate diarrhoea causes Change formula
Hyperphosphataemia
Renal insufficiency
Hyperglycaemia Hypokalaemia Hyperkalaemia
2. Mechanical complications 2.1. Aspiration Pulmonary aspiration is extremely serious and may be a life threatening complication, with an incidence of 1–4%. Symptoms include dyspnoea, tachypnea, wheezing, tachycardia, agitation and cyanosis. Fever in EN fed patients may be a delayed symptom of aspiration pneumonia, caused by small amounts of formula aspiration. Risk factors for aspiration include: -
decreased level of consciousness; diminished gag reflex; neurological impairment; incompetent lower esophageal sphincter; GI reflux; supine position; use of large bore feeding tubes; large gastric residues.
Increase phosphate intake Decrease energy load Change formula
a gastrostomy tube should be placed instead of a nasogastric one. Stoma sites may also present complications, with leakage indicating tube dysfunction, infection or incorrect stoma size. Tube dysfunction can be solved with tube replacement, whereas infection requires medication and eventually tube removal. 2.3. Tube clogging
In order to reduce the risk of aspiration, periodic assessment of gastric residue should be undertaken, in association with prokinetic drugs. Nasojejunal feeding is less associated with aspiration pneumonia, and therefore should be preferred in high risk patients. Another standard of practice in these patients, is keeping the head of the bed elevated, maintaining a semi recumbent position (45 ).
Obstruction is a very common complication during EN. Most clogging is secondary to coagulation or inadequate flushing of the tube after feeding of formula. And it is more likely to occur with intact protein and viscous products. Other causes of obstruction include administering medication, which may fragment and precipitate, and tube kinking. The rate of tube obstruction is related to tube diameter, quality of nursing care, tube type (jejunostomy vs. gastrostomy) and duration of tube placement. Dislodging the obstruction is usually preferable to tube replacement. Experienced nurses use various methods to unclog feeding tubes, from warm water alternating with gentle pressure and suction to pancreatic enzymes and sodium bicarbonate solution to help ‘‘digest’’ the precipitate (Table 1).
2.2. Tube related complications
3. Metabolic complications
Tube malposition could cause bleeding and tracheal, parenchymal or GI tract perforation. These complications can be minimized, through the use of trained staff and adequate postplacement monitoring. Presence of the feeding tube itself may cause necrosis, ulceration and abscess formation of the nasopharyngeal, oesophageal, gastric and duodenal points of contact. It may cause upper and lower airway complications, aggravate oesophageal varices, necrotizing fascitiis, fistulas, and wound infections. Use of soft small bore feeding tubes and attentive nursing care can help reduce many of these problems. When long term EN is anticipated,
Metabolic complications of EN are, in fact, very similar to those occurring during parenteral nutrition, despite their lower incidence and severity. Careful monitoring can help reduce or prevent these problems, which are detailed in the following table (Table 2):
Table 1 Complications of enteral nutrition.
3.1. Refeeding syndrome Refeeding of severely malnourished or long term fasting patients may result in ‘‘refeeding syndrome’’, this metabolic complication is connected both with enteral and parenteral nutrition. 4. Summary
Gastrointestinal (30–38%)
Mechanical (2–10%)
Abdominal cramping Abdominal distension Nausea and vomiting Oesophageal reflux Diarrhoea Malabsorption GI bleeding Ileus
Rhinitis, otitis, parotitis Pharingitis, oesophagitis Pulmonary aspiration Oesophageal erosions Tube dislodgment Tube obstruction Perforation
The type and frequency of complications during EN may be related to the formulation and delivery of the diets, as well as the underlying disease. There are three major categories of EN complications: gastrointestinal, mechanical and metabolic. GI complications are undoubtedly the most frequently described. Careful consideration should be given to the use of enteral nutrition therapy, but once implemented, close monitoring of patients is an efficient safeguard against complications and side effects. Similarly
G. Bodoky, L. Kent-Smith / e-SPEN, the European e-Journal of Clinical Nutrition and Metabolism 4 (2009) e209–e211
to the development of an enteral product formulary, standards of practice for delivery and monitoring of EN should be established and followed by all the staff involved in nutritional therapy. Conflict of interest There is no conflict of interest.
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Further reading 1. Rombeau JL, Rolandelli RH, editors. Enteral and tube feeding. 3rd ed. W.B. Saunders; 1997. 2. Russell M, Cromer M, Grant J. Complications of enteral nutrition. In: Gottschlich M, editor. The science and practice of nutrition support. ASPEN; 2001. p. 189. 3. American Gastroenterological Association Medical Position Statement. Guidelines for the use of enteral nutrition. Gastroenterology; 1995::1280.
