A 63-year-old female with a BMI of 55 is admitted to the ICU with a necrotizing soft tissue infection. She is intubated and enteral tube feeds are started. If indirect calorimetry is not available, how should her calorie requirements be estimated?
Correct Answer: A
Indirect calorimetry is the gold standard for predicting calorie needs. In obese ICU patients this is particularly true as predictive formulas do not come within 10% of actual resting energy expenditure as measured by IC. In the absence of IC, ASPEN guidelines recommend using a weight-based formula of 22 to 25 kcal/kg/d of ideal body weight for patients with a BMI >50, providing 65% to 75% of caloric requirements, to allow for steady weight loss and some of the associated benefits of weight loss including decreased insulin resistance. For patients with a BMI of 30 to 50 the recommended predictive formula is 11 to 14 kcal/kg/d.
Reference:
Indirect calorimetry determines energy expenditure by measuring:
Correct Answer: C
Indirect calorimetry takes minutes to perform and measures diluted concentrations of O2 and CO2 of a patient breathing at rest. A pulmonary artery catheter and arterial line can be used to estimate O2 consumption, but this has been shown to underestimate the absolute number when compared to the gold standard of respiratory indirect calorimetry. Measuring the heat and steam released by the body is how direct calorimetry is performed and presents a significant cost challenge.
References:
A 56-year-old male is admitted with severe acute pancreatitis due to alcohol ingestion. Appropriate management of his nutrition includes:
Correct Answer: D
Multiple studies have indicated the benefits of continued enteral nutrition during severe acute pancreatitis. When compared to parenteral nutrition, enteral nutrition reduces infectious morbidity, multi-system organ failure, and mortality.
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