Answers to Self-Assessment Questions - ACCP

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A), chromium (Answer B), and selenium (Answer C) concentrations have been reported to be decreased in patients receiving CRRT; therefore, these trace elements should be supplemented in patients receiving CRRT, making Answers A, B, and C incorrect. 1. Klein CJ, Moser-Veillon PB, Schweitzer A, Douglass LW, Reynolds HN, Patterson KY, et al. Magnesium, calcium, zinc, and nitrogen loss in trauma patients during continuous renal replacement therapy. JPEN J Parenter Enteral Nutr 2002;26:77–92. 2. Berger MM, Shenkin A, Revelly JP, Roberts E, Cayeux MC, Baines M, et al. Copper, selenium, zinc, and thiamine balances during continuous venovenous hemodiafiltration in critically ill patients. Am J Clin Nutr 2004;80:410–6. 3. Story DA, Ronco C, Bellomo R. Trace element and vitamin concentrations and losses in critically ill patients treated with continuous venovenous hemofiltration. Crit Care Med 1999;27:220–3. 4. Answer: C Because of fluid overload, A.B.’s usual weight (82 kg) or his most recent preadmission weight (70 kg) should be used to calculate his caloric requirements. B.A.’s estimated caloric requirement is 25–35 kcal/kg/day. Answer C (2460 kcal/day) provides 30 kcal/kg/day based on B.A.’s usual body weight (82 kg) or 35 kcal/kg/day based on his most recent preadmission weight, and is therefore the best answer. Answer A (1230 kcal/kg/day) and Answer B (1640 kcal/ kg/day) provide fewer than 25 kcal/kg/day; these amounts are less than recommended for patients like B.A. Answer D (3280 kcal/kg/day) provides more than 35 kcal/kg/day, which would be an excessive daily caloric intake for B.A. leading to complications associated with overfeeding. 1. Liu KD, Stralovich-Romani A, Chertow GM. Nutrition support for adult patients with acute renal failure. In: Merritt R, ed. The A.S.P.E.N. Nutrition Support Practice Manual, 2nd ed. Silver Spring, MD: American Society for Parenteral and Enteral Nutrition, 2005:281–6. 2. A.S.P.E.N. Board of Directors and The Clinical Guidelines Task Force. Guidelines for the use of parenteral and enteral nutrition in adult and pediatric patients. JPEN J Parenter Enteral Nutr 2002;26S:1SA–6SA. 5. Answer: C B.A. is receiving CRRT with citrate anticoagulation and has developed metabolic alkalosis. In this situation, bicarbonate administration should be decreased (Answer C); thus Answer C is the correct answer. Citrate is converted by the liver to bicarbonate and may precipitate alkalosis if the patient is not monitored closely or if intake of other buffer solutions (bicarbonate, lactate, and acetate) is not reduced. Answer A (lactate solutions should be used to correct B.A.’s alkalosis) is incorrect because lactate-containing solutions have been shown to have a negative effect on cardiac function and mean arterial pressure. These effects would be undesirable in B.A., who has chronic heart failure and shock. Additionally, lactate is converted to bicarbonate in the liver, which would exacerbate B.A.’s alkalosis. Bicarbonatebased solutions (Answer B) are not indicated because of the potential for worsening B.A.’s alkalosis; thus Answer B is incorrect. Acetate solutions (Answer D) should not be used routinely in patients in the intensive care unit (ICU) because Gastroenterology and Nutrition Answers 36 vasodilation and reduced myocardial contractility have been observed. These effects along with the conversion of acetate by the liver to bicarbonate may worsen the alkalosis. Therefore, Answer D is incorrect. 1. Gabutti L, Marine C, Colucci G, Duchini F, Schönholzer C. Citrate anticoagulation in continuous venovenous hemodiafiltration: a metabolic challenge. Intensive Care Med 2002;28:1419–25. 2. Druml W. Metabolic aspects of continuous renal replacement therapies. Kidney Int Suppl 1999;72:S56–S61. 6. Answer: B J.G.’s traumatic injury (Answer B) will increase her energy requirements compared with a healthy woman of her age and weight because hypermetabolism that occurs with trauma increases energy needs; thus Answer B is correct. The presence of ARF (Answer A) does not increase a patient’s basal metabolic expenditure, making Answer A is incorrect. In general, women have lower energy requirements compared with men, making Answer C (female sex) incorrect. Answer D (hypothermia from the absence of a blood warmer for the CRRT replacement solutions) is incorrect because hypothermia would induce a hypometabolic response, reducing energy needs. 1. Marin A, Hardy G. Practical implications of nutritional support during continuous renal replacement therapy. Curr Opin Clin Nutr Metab Care 2001;4:219–25. 2. A.S.P.E.N. Board of Directors and the Clinical Guidelines Task Force. Guidelines for the use of parenteral and enteral nutrition in adult and pediatric patients. JPEN J Parenter Enteral Nutr 2002;26S:1SA–6SA. 3. Uehara M, Plank LD, Hill GL. Components of energy expenditure in patients with severe sepsis and major trauma: a basis for clinical care. Crit Care Med 1999;27:1295–302. 7. Answer: A J.G. is receiving CVVHD using a dialysis solution containing dextrose 2% at a rate of 1 L/hour, which will supply 480 g of dextrose per day. Because an estimated 35% to 45% of dextrose in the CRRT dialysate is absorbed, 168–216 g of dextrose per day would be absorbed from J.G.’s dialysate. This dextrose delivery should be accounted for in J.G.’s nutrition regimen, necessitating a decrease in the amount of dextrose administered through modalities other than CRRT. Decreasing the dextrose in the PN formulation by about 200 g/day (Answer A) is therefore the best option. Decreasing the dextrose in the PN by 480 g/day (Answer B) is incorrect because it represents 100% absorption of the dextrose being supplied through CRRT when only 35% to 45% is actually absorbed. Therefore, decreasing the dextrose delivery by 480 g/day would result in a caloric deficit. Answer C (increase dextrose by 200 g/day) and Answer D (increase dextrose by 480 g/day) are incorrect because dextrose in the PN formulation should be decreased, not increased, to avoid overfeeding and its inherent risks. 1. Bellomo R, Martin H, Parkin G, Love J, Kearley Y, Boyce N. Continuous arteriovenous haemodiafiltration in the critically ill: influence on major nutrient balances. Intensive Care Med 1991;17:399–402. 2. Marin A, Hardy G. Practical implications of nutritional support during continuous renal replacement therapy. Curr Opin Clin Nutr Metab Care 2001;4:219–25. Pharmacotherapy Self-Assessment Program, 6th Edition
8. Answer: A J.G. is receiving propofol at 11 mL/hour, which provides 1.1 kcal/mL through its vehicle (10% fat emulsion). This amount of propofol will provide 290 kcal/day and 29 g of fat per day. The amount of fat emulsion in J.G.’s PN formulation must be reduced to avoid overfeeding. Decreasing the lipid emulsion by 29 g/day (Answer A) will reduce the fat intake by about the same amount of fat being provided by the propofol drip; making Answer A the best answer. Decreasing lipid emulsion by 53 g/day (Answer C) would decrease the lipid delivery by an amount that exceeds that being provided by the propofol drip, making Answer C is incorrect. Answer B (increase lipid emulsion by 29 g/day) and Answer D (increase lipid emulsion by 53 g/day) are incorrect because the lipid content should be reduced to avoid overfeeding. Once the propofol drip is discontinued, readjustment of the PN formulation will be required. 1. Lowrey TS, Dunlap AW, Brown RO, Dickerson RN, Kudsk KA. Pharmacologic influence on nutrition support therapy: use of propofol in a patient receiving combined enteral and parenteral nutrition support. Nutr Clin Pract 1996;11:147–9. 2. Mateu-de Antonio J, Barrachina F. Propofol infusion and nutrition support. Am J Health Syst Pharm 1997;52:2515–6. 9. Answer: C Thiamine (Answer C) should be supplemented in J.G.’s PN formulation because it is lost in significant amounts during CRRT, making Answer C the correct answer. Thiamine is important in dextrose metabolism, and supplementation of 50–100 mg/day is recommended for patients receiving CRRT. Vitamin A (Answer A) and vitamin D (Answer B) are fat-soluble and are not removed to any appreciable degree during CRRT, so Answer A and Answer B are incorrect. Although vitamin C (Answer D) is lost in the CRRT filtrate, the clinical significance of this loss is unknown, and vitamin C supplementation is not currently recommended; thus Answer D is incorrect. 1. Berger MM, Shenkin A, Revelly JP, Roberts E, Cayeux MC, Baines M, et al. Copper, selenium, zinc, and thiamine balances during continuous venovenous hemodiafiltration in critically ill patients. Am J Clin Nutr 2004;80:410–6. 2. Story DA, Ronco C, Bellomo R. Trace element and vitamin concentrations and losses in critically ill patients treated with continuous venovenous hemofiltration. Crit Care Med 1999;27:220–3. 10. Answer: D In patients like J.G. (weight 60 kg) receiving CRRT, protein intakes of 2.5 g/kg/day have been shown to optimize nitrogen balance; thus Answer D (150 g/day) is correct. Protein intakes less than 2.5 g/kg/day have been associated with serum amino acid concentrations below the reference range, whereas protein intakes of 2.5 g/kg/day are associated with a normalization of serum amino acid concentrations and a higher prevalence of positive nitrogen balance. Answer A (60 g/day), Answer B (90 g/day), and Answer C (120 g/day) provide only 1 g/kg/day, 1.5 g/kg/day, and 2 g/kg/day of protein, respectively; therefore, Answer A, Answer B, and Answer C are incorrect because the protein intake is insufficient to meet J.G.’s needs. 1. Scheinkestel CD, Adams F, Mahony L, Bailey M, Davies AR, Nyulasi I, et al. Impact of increasing parenteral protein loads on amino acid levels and balance in critically ill anuric patients on continuous renal replacement therapy. Nutrition 2003;19:733–40. 2. Scheinkestel CD, Kar L, Marshall K, Bailey M, Davies A, Nyulasi I, et al. Prospective randomized trial to assess caloric and protein needs of critically ill, anuric, ventilated patients requiring continuous renal replacement therapy. Nutrition 2003;19:909–16. 11. Answer: C In patients like J.G. with ARF, there are derangements of serum amino acids. Studies have demonstrated that patients with ARF should receive an essential–nonessential amino acid combination when PN is required; thus, Answer C (essential plus nonessential amino acid combination formulation) is the correct option for J.G.’s PN formulation. Essential amino acid–only formulations (Answer A) are more costly than standard amino acid formulations and have not been shown to produce a clinical benefit; thus Answer A is incorrect. A nonessential amino acid formulation (Answer B) would put J.G. at risk of amino acid deficiencies if essential amino acids were not provided, so Answer B is incorrect. Modular protein formulations (Answer D) are not available for administration in PN formulations but are used in enteral nutrition (EN) to supplement oral intake or tube feeds; therefore, Answer D is incorrect. 1. A.S.P.E.N. Board of Directors and the Clinical Guidelines Task Force. Guidelines for the use of parenteral and enteral nutrition in adult and pediatric patients. JPEN J Parenter Enteral Nutr 2002;26S:1SA–6SA. 2. Mirtallo JM, Schneider PJ, Mavko K, Ruberg RL, Fabri PJ. A comparison of essential and general amino acid infusions in the nutritional support of patients with compromised renal function. JPEN J Parenter Enteral Nutr 1982;6:109–13. 3. Feinstein EI, Blumenkrantz MJ, Healy M, Koffler A, Silberman H, Massry SG, et al. Clinical and metabolic responses to parenteral nutrition in acute renal failure: a controlled doubleblind study. Medicine 1981;60:124–37. 12. Answer: B J.G. has ARF and is receiving CVVHD with citrate anticoagulation. Her condition and therapies put her at risk of both calcium and phosphorus imbalance. Close monitoring of serum ionized calcium and phosphorus concentrations is vital; therefore, Answer B (calcium balance should be frequently assessed by monitoring J.G.’s serum ionized calcium and serum phosphorus concentrations) is correct. The serum ionized calcium is more reliable in patients with hypoalbuminemia, which is common in ARF. Answer A (citrate anticoagulation will likely induce hypercalcemia, thus requiring a reduction in the amount of J.G.’s calcium intake) is incorrect because citrate anticoagulation would likely induce hypocalcemia because of calcium chelation by citrate. Because calcium is filtered by CRRT, hypocalcemia may develop, and the need for calcium supplementation is common in patients receiving CRRT; therefore, Answer C (hypocalcemia is rare in patients such as J.G. with ARF receiving CRRT, and calcium supplementation will not be required) is incorrect. Hyperphosphatemia is unlikely because phosphorus is removed by CRRT; however, this would not preclude correction of hypocalcemia, if necessary. Therefore, Answer D (calcium supplementation in J.G. Pharmacotherapy Self-Assessment Program, 6th Edition 37 Gastroenterology and Nutrition Answers
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Answers to Self-Assessment Questions - ACCP

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