ENTERAL NUTRITIONAL SUPPORT
From Cerra FB: How nutrition changes what getting sick means, J Parenter Enteral Nutr 14:164S, 1990.
Ne, No change; —, decrease; +,increase.
Enteral nutritional support is a practical, safe, easy, economic, physiologic, and well-tolerated technique with minimal morbidity; however, it requires
BOX 12-2
Possible Indications for Nutritional Support
Patients Known to Be Protein-Energy Malnourished
Any patient in critical care unit
Recent weight loss of ≥5% to 10% of body weight Decreased food intake or anorexia for ≥3 to 5 days Generalized loss of muscle mass or body fat Generalized weakness and lethargy for ≥5 days Hypoalbuminemia
Lymphopenia unassociated with severe stress or drug therapy
Presence of a nonhealing wound, delayed wound healing, or a decubital ulcer
Presence of a chronic, unrelenting fever or other signs of infection or sepsis
Poor body condition characterized by easily epilated hair and cracked nails
Patients With Conditions Known to Cause Protein-Calorie Malnutrition
Recent severe trauma or major surgery
Resection of ≥70% of the small intestine
Chronic vomiting or diarrhea
Protein-losing nephropathies
Increased nutrient needs with neoplasia
Peritonitis, pleuritis, or chylous effusion with effective, progressive drainage
Large wounds or burns, with persistent exudative losses Use of drugs that promote catabolism
Chronic or massive hemorrhage
Cachexia
Patients With Conditions Associated With Poor Food Intake
Fractures of the mandible or maxilla
Congenital hard- or soft-palate clefts
Recovery from major oral or nasal surgery
Severe generalized stomatitis, glossitis, pharyngitis, and esophagitis
Severe periodontal disease
Neurologic conditions associated with coma or seizures requiring sedation
Tetraplegia that prevents patient from eating
Bilateral cranial nerve V or XII palsies
Severe oropharyngeal or cricopharyngeal dysphagia Megaesophagus
Esophageal stricture or foreign body
Following esophageal resection
Following extensive stomach disease, surgery, or resection
Following extensive intestinal surgery or resection
Anorexia with refusal to eat because of various metabolic diseases (e.g., renal failure, pancreatitis, hepatic failure)
Severe persistent vomiting
Withholding food for ≥3 to 5 days because of therapeutic or diagnostic procedures
| TABLE 12-2 | Body Condition Scoring System Based on a 5-Point or 9-Point Scale | ||
| Descriptor | Description | 5 Point | 9 Point |
| Cachectic | Ribs are easily palpated with no fat cover; bony structures are prominent and easy to identify; muscle tone and mass often decreased; little to no subcutaneous fat; hair coat often poor; pronounced abdominal tuck | 1 | 1 |
| Underweight | Ribs are easily palpated with little fat cover; abdominal tuck present; bony structures are palpable but not prominent; hair coat may be poor; muscle tone and mass may be good or slightly decreased | 2 | 3 |
| Ideal | Ribs are easily palpated, but fat cover is present; hourglass shape present and abdominal tuck is present, but not pronounced; bony prominences are palpable but not visible; some subcutaneous fat, but no large accumulations; muscle tone and mass good; hair coat quality is good | 3 | 5 |
| Overweight | Ribs are difficult to palpate due to overlying fat accumulation; hourglass shape is not prominent, and abdominal tuck is absent; subcutaneous fat obvious with some areas of accumulation; muscle tone and mass good; hair coat quality may be decreased; cannot identify bony prominences | 4 | 7 |
| Obese | Ribs are impossible to palpate due to overlying fat; hourglass shape is absent, and animal may have a round appearance; subcutaneous fat is obvious, and accumulations are present in the neck, tail-base, and abdominal regions; muscle tone and mass may be decreased; hair coat quality may be decreased | 5 | 9 |
a functional GI tract. It is the preferred method to efficiently achieve nitrogen balance and accelerate wound healing.
Simply put, “If the gut works, use it.”Indications
Enteral nutritional support is indicated in any patient with overt or impending protein-calorie malnutrition in which the GI tract is functional.
Examples include patients in a hypermetabolic state (e.g., severe burn, sepsis, postsurgical stress, trauma, cancer); patients with chronic anorexia/ malnutrition, as evidenced by greater than 10% loss of normal body weight and hypoalbumine- mia; postoperative patients in whom 5 to 7 days of anorexia has occurred or is anticipated (e.g., oral, pharyngeal, esophagogastric, duodenal, pancreatic, or biliary tract surgery); postoperative cancer patients, particularly if chemotherapy is instituted; and patients with a mental status that prevents adequate self-feeding (e.g., head trauma, brain surgery). In virtually any situation in which the clinician has diagnosed protein-calorie malnutrition or can predict its occurrence, enteral nutritional support should be considered.BOX 12-3
Route of Administration Determines Tube Diameter
Tube Diameter: 3.5 to 5 Fr
• Nasoesophageal
• Gastroduodenostomy
• Enterostomy
Tube Diameter: ≥8 Fr
• Orogastric
• Nasoesophageal (dogs >22 lb)
• Esophagostomy
• Pharyngostomy
• Gastrostomy diameter; tube diameter in turn dictates usable feeding formulas because of varying formula viscosity and particulate matter size (Box 12-3).
The most common routes of administration for enteral alimentation include oral, nasoesophageal, pharyngostomy, esophagostomy, gastrostomy, gas- troduodenostomy, and enterostomy. Each route has its indications, contraindications, advantages, disadvantages, and complications.
Contraindications
Enteral nutritional support may be contraindicated in several situations. Patients with adynamic ileus, small bowel obstruction, severe intrinsic small bowel disease (e.g., inflammatory bowel disease, diffuse intestinal lymphosarcoma), persistent vomiting or diarrhea, or severe malabsorption should have nutrients delivered by routes other than the GI tract. In addition, patients at risk for aspiration pneumonia (e.g., stupor or coma) should not be fed via the GI tract.