256

Part II Nutrition Assessment, Consequences, and Implications

(18). Box 18.3 lists contraindications to enteral nutri- tion support.

BOX 18.3 Contraindications to Enteral Nutrition Support

●●

Malnourished individuals expected to eat within 5 to 7 days

●● Severe acute pancreatitis ●●High output proximal fistula ●● Inability to gain enteral access ●● Intractable vomiting or diarrhea ●●Aggressive therapy not warranted

●●

Expected need less than 5 to 7 days if malnourished or 7 to 9 days if normally nourished

Source: A.S.P.E.N. Board of Directors and Society of Critical Care Medicine. Nutrition guidelines for the provision and assessment of nutrition support therapy in the adult critically ill patient. JPEN J Parenter Enteral Nutr. 2010;33:3.

Enteral Feeding Access

Once enteral nutrition is decided upon, selecting the most appropriate enteral access is the next step. “Determining the optimal access route for enteral nutrition depends on the anticipated duration of therapy, gastric function, lower esophageal sphincter competence, and the risk of aspiration” (19). Most older adults who receive a tube feeding due to dyspha- gia can tolerate a gastric feeding. Those with gastropa- resis/gastric ileus, significant gastroesophageal reflux, aspiration risk, or pancreatitis should have the feeding tube placed into the small bowel.

Nasogastric/Enteric Feeding-Tube Placement

Clients who require enteral nutrition support for fewer than four to six weeks may benefit from a feeding tube placed through the nose into the stomach, duodenum, or proximal jejunum. Nasogastric/enteric tubes are generally made of soft, biocompatible materials, such as polyurethane or silicone. These tubes range in length from 90 cm (nasogastric) to 150 cm (intestinal). Older adults with gastroparesis or diseases involving the stomach or those at risk for pulmonary aspiration may require a tube placed beyond the pylorus into the small bowel (16,19,20).

Nasoduodenal and nasojejunal feeding tubes may be placed by a variety of methods, including the fol- lowing (19):

●●

spontaneous passage, in which the tube migrates to the small bowel by peristalsis or with the help of prokinetic agents (eg, erythromycin);

●● active bedside placement; or ●● fluoroscopic and endoscopic methods.

The method used depends on the training of the clini- cian and availability of equipment.

Enterostomy Feeding-Tube Placement Persons who require access to the GI tract for more than four to six weeks may have a gastrostomy or jeju- nostomy tube placed surgically, endoscopically, or radiologically. A surgical gastrostomy is performed under general anesthesia in the operating room, whereas a percutaneous endoscopic gastrostomy may be performed at the bedside or in an endoscopic suite with local anesthesia. “Gastrostomy tubes are indicated when gastric emptying is normal, a gag reflex is present, and there is no esophageal reflux” (19). Jejunostomy feeding tubes are generally placed at the time of a surgical procedure or may be placed endoscopically (percutaneous endoscopic jejunos- tomy). Indications for jejunal feeding tubes include severe esophageal reflux, obstruction, stricture, fistula or ileus of the upper GI tract, or risk for pulmonary aspiration (19).

Enteral Formula Selection

There are a multitude of formulas available for enteral nutrition support. These formulas can be grouped into three main categories: polymeric, hydrolyzed, and modular. They further have varying caloric density ranging from levels of 1 kcal/mL, 1.5 kcal/mL, and 2 kcal/mL. It is important to evaluate the nutritional adequacy of a formula based on the kcal provided to the patient and not the mL of formula provided. Selection of an appropriate formula is based on several factors, including digestive and absorptive capacity, volume status, and overall disease state (see Table 18.1). The goal of an enteral feeding is to use the most cost-effective formula that meets the patient’s nutrition needs (19).

Polymeric Formulas

These formulas are nutritionally complete, predomi- nantly lactose-free, and casein- or soy protein isolate based. Normal digestion and absorption are required, as nutrients are in an intact molecular form. Polymeric formulas supply all necessary nutrients for complete nutrition, generally in 2 L or less. The following variet- ies of polymeric formulas are available: standard, high nitrogen, fiber supplemented, concentrated, and disease specific (ie, renal, hepatic, glucose intolerance,