Enteral Nutrition Support Therapy for Adults
Manual of Clinical Nutrition Management B- 40 Copyright © 2013 Compass Group, Inc.
patients with refractory (chronic) encephalopathy that is unresponsive to pharmacotherapy (1,2,39).Disease-specific formulas include:
Formulas for renal disease: Renal formulas are energy-dense formulas that contain whole proteins and
have a modified electrolyte content (eg, sodium, potassium, phosphorus, and magnesium). These
formulas may be indicated in renal patients whose serum electrolyte levels are difficult to manage or for
whom renal dialysis is delayed (15). ASPEN recommendations suggest that ICU patients with acute renal
failure receive standard enteral formulations and that standard ICU recommendations for protein and
energy provision should be followed (5). If significant electrolyte abnormalities exist or develop, then a
specialty formulation designed for renal failure (with an appropriate electrolyte profile) may be
considered (5).
Most specialty renal formulas are energy dense, so that volume can be restricted if needed. The protein
content ranges from less than 40 g to more than 70 g in 2,000 kcal. These formulas meet the Dietary
Reference Intakes for most nutrients with the exception of select vitamins, minerals, and electrolytes that
are normally restricted in renal insufficiency (eg, potassium, sodium, phosphorus, and magnesium). If
dialysis is delayed, an energy-dense, reduced-protein formula is appropriate (40). However, long-term use
of these formulas requires close monitoring of the patient’s nutritional status (15). Patients receiving
hemodialysis or continuous renal replacement therapy should receive increased protein, up to a
maximum of 2.5 g/kg per day (5). Protein should not be restricted in patients with renal insufficiency as a
means to avoid or delay the initiation of dialysis therapy (5,15,41). The nutrition goals of patients with
renal failure should include adequate protein and energy intake, with modifications in fluid volume and
electrolyte content that are individualized based on the patient’s clinical condition. There is insufficient
data to determine if renal formulas produce different outcomes than standardized formulas (5,42). Formulas for hepatic disease: Standard formulations should be used in ICU patients with acute and
chronic liver disease (1,4,5,15). Nutrition regimens should avoid restricting protein in patients with liver
failure (5). Special enteral formulas have been designed for patients with hepatic failure. These formulas
are modified in fluid, protein, and mineral content and may not meet the Dietary Reference Intakes for
various nutrients. These formulas contain increased levels of BCAA along with decreased levels of
aromatic amino acids in an attempt to treat or prevent hepatic encephalopathy. The total protein content
varies among formulas and is often low. Studies of these formulas are inconclusive (5,39). The BCAA-
enhanced formulations should be reserved for the rare encephalopathic patient who is refractory to
standard treatment with luminal-acting antibiotics and lactulose (5,39).
Formulas for pulmonary disease and ARDS: Pulmonary disease formulas are low in carbohydrate and
high in fat to decrease carbon dioxide (CO 2 ) production in patients with compromised pulmonary
function. Formulas that contain omega-3 fatty acids may be beneficial in patients with early ARDS (1). The
ASPEN guidelines, which are based on a comprehensive review of studies, suggest that critically ill ARDS
patients receive enteral formulations that have an anti-inflammatory lipid profile (eg, omega-3 fish oils,
borage oil) and contain antioxidants (5). The Academy of Nutrition and Dietetics provides similar
guidelines which recommend the use of immune-modulating formulas with fish oil, borage and
antioxidants to be considered for intensive care unit (ICU) patients with acute respiratory distress
syndrome (ARDS) or acute lung injury (Grade II) (3).The evidence regarding the impact of higher fat and
lower carbohydrate enteral formula composition on CO 2 production is still limited. Although a few
studies have shown decreased CO 2 levels in hypercapnic patients who received these formulas (28,43),
more data are needed. Talpers et al found that an excess of total energy was as deleterious to CO 2
production as carbohydrate intake (43). Thus, an excess of total energy should be avoided, and energy
intake should be equal to or less than the energy needs of patients with pulmonary disease and CO 2
retention (1,15). The high lipid content of these formulas may cause delayed gastric emptying (44). These
formulas tend to contain intact nutrients and are usually low in fluid and nutritionally complete. Fluid-
restricted, energy-dense formulations (1.5 to 2.0 kcal/mL) should be considered for patients with acute
respiratory failure to prevent fluid accumulation and pulmonary edema (5). If pulmonary formulas are
used, the patient’s ventilatory status and CO 2 production should be monitored, and overfeeding should be
avoided (2,15).
Formulas for diabetes mellitus: Patients with diabetes mellitus who follow a diet with increased intake
of monounsaturated fatty acids along with lower carbohydrate intake may have improved blood glucose
control (15). Therefore, enteral formulas with modified amounts and types of carbohydrate and fat have