Which of the following is not a proposed mechanism by which enteral feeding decreases bacterial intestinal wall translocation when compared to IV nutrition?
A. Preserved local cytokine expression pattern
B. Increased villous height and over all mucosal mass
C. Bactericidal activity of enteral nutritioncomponents
D. Stimulation of intraluminal IgA transportation
C. Bactericidal activity of enteral nutrition components. Multiple mechanisms have been proposed for the morphological and functional differences observed in the intestinal epithelium with parenteral nutrition (PN) when compared to enteral nutrition. It has repeatedly been demonstrated that small bowel mucosal mass is lost with only PN. Yang and colleagues demonstrated that the administration of 25% enteral nutrition reversed the abnormal IL-10, IL-4, and IL-6 messenger RNA (mRNA) expression that had resulted from only PN support in animal models. This is of particular significance as these changes in cytokine expression were associated with epithelial leak and an increased rate of enterocyte apoptosis.
It has also been shown that the type and route of nutrition affect pIgR expression in an organ-specific manner; pIgR represents the exclusive transport pathway for IgA to move from the lamina propria, through the epithelia, into the lumen of the gut where it acts as a key component in the gut’s defense. Enteral nutrition components are not bactericidal and actually help preserve normal flora.
Which of the following stressors results in the greatest increase in energy expenditure above basal metabolic needs?
D. Burns. Energy requirements above basal needs are approximately 10% for elective operations, 10%-30% for trauma, 50%-80% for sepsis, and 100%-200% for burns. Burns covering more than 40% total body surface area (TBSA) are typically followed by a period of severe stress, characterized by an exaggerated catabolic state. Increases in catecholamine, glucocorticoid, glucagon, and dopamine secretion are thought to initiate the cascade of events leading to the acute hypermetabolic response with its ensuing catabolic state. Appropriate nutrient delivery can be accomplished by feeding 1.2-1.4 times the measured resting energy expenditures (REEs).
Regarding centrally administered parenteral nutrition in the critically ill patient, which of the following is not true?
A. An initial formulation for nonamino acid calories is generally advised to consist of 70% dextrose and 30% fat emulsion.
B. TPN should be avoided if anticipated use is less than 6-7 days.
C. The recommended amino acid dose ranges from 0.8 to 1 g/kg.
D. The line-related complication rate from CVCs is greater than 15%.
C. The recommended amino acid dose ranges from 0.8 to 1 g/kg. The recommendation for the amino acid dose ranges from 1.2 to 1.5 g/kg/d for most patients with normal renal and hepatic function, although some sources recommend higher doses. TPN via a central line is indicated for patients who cannot obtain adequate nourishment via the gastrointestinal tract for a minimum duration of treatment of 7-10 days. The use of postoperative TPN for only 2 or 3 days is highly discouraged, as the risks outweigh the benefits incurred over this short period of time. A reasonable initial guideline is to provide 60%-70% of nonamino acid calories as dextrose and 30%-40% of nonamino acid calories as fat emulsion. The placement of central line catheters always carries risks; the overall complication rate related to this access is greater than 15%.Femoral vein access carries the highest risk of infection and should be avoided if possible.
Which of the following is true?
A. Lactose intolerance is most prevalent in European Caucasians when compared to other populations.
B. Gastric residuals of 100 cc should prompt holding of tube feeds.
C. Gastric bypass patients are prone to deficiencies of the fat-soluble vitamins, calcium, iron, vitamin B12, and folate.
D. Enteral nutrition carries a technical complication rate of 10%.
C. Gastric bypass patients are prone to deficiencies of the fat-soluble vitamins, calcium, iron, vitamin B12, and folate. Gastric bypass procedures intentionally limit the amount of oral intake and decrease the amount of small bowel that takes part in absorption. This renders the population of patients prone to deficiencies of the fat-soluble vitamins (A, D, E, and K), calcium, iron, vitamin B12, and folate. Careful attention should be paid to ensuring that these deficiencies are countered with supplementation. Technical complications occur in about 5% of enterally fed patients and include clogging of the tube; esophageal, tracheal, bronchial, or duodenal perforation; and tracheobronchial intubation with tube feeding aspiration. Lactose intolerance is least common in European Caucasians, present within only 5%-10% of this population. Although recommendations differ depending on source, enteral feeds are not typically held until gastric residuals of greater than 200 cc are encountered.
Regarding nutritional indices, which of the following is false?
A. PNI has been validated in patients undergoing either major cancer or gastrointestinal surgery and found to accurately identify a subset of patients at increased risk for complications.
B. The NRI is an excellent tool for tracking the adequacy of nutritional support.
C. The MNA is a rapid and reliable tool for evaluating the nutritional status of the elderly.
D. SGA is a reproducible clinical method that has been validated and encompasses the patient’s history and physical examination.
B. The NRI is an excellent tool for tracking the adequacy of nutritional support. The NRI is an index that has been prospectively crossvalidated against other nutritional indices with good results, but is not a good tool for tracking the adequacy of nutritional support, since supplemental nutrition often fails to improve serum albumin levels. The index successfully stratifies perioperative morbidity and mortality using serum albumin and weight loss as predictors of malnutrition.