Predicted vs measured energy expenditure in critically ill, underweight patients.
A retrospective analysis was conducted to compare 4 energy-prediction equations against measured resting energy expenditure (MREE) determined via indirect calorimetry. Data from a heterogeneous group of 42 critically ill, severely underweight (59.50 +/- 17.30 kg; 77.1 +/- 9.7% ideal body weight [IBW]) male patients were assessed. The Hamwi formula was used to determine IBW. The Harris-Benedict (HB) equation was calculated for patients <90% IBW using both current body weight (CBW) and IBW. Energy needs were also estimated with an Ireton-Jones formula for all mechanically ventilated patients (n = 37). For patients <85% IBW (n = 31), an adjusted body weight was determined ([CBW + IBW]/2) and used in the HB formula. The HB formula using the IBW, CBW, and adjusted body weight was significantly different (p < .05) than MREE. The Ireton-Jones equation was not significantly different (p > .05) from MREE but tended to overestimate energy needs (109.3% +/- 16.8% MREE). Conversely, using the CBW or IBW in the HB underestimated the patient's energy needs; 77.0% +/- 11.6% MREE and 90.9 +/- 16.1% MREE, respectively. For patients <85% IBW, use of the adjusted body weight in the HB represented 84.2% +/- 13.9% MREE. The average caloric need was 31.2 +/- 6.0 kcal/kg CBW. Indirect calorimetry remains the best method of determining a patient's energy needs. Until a large prospective trial is conducted, a combination of prediction equations tempered with clinical judgment and monitoring the appropriateness of the nutrition prescription remains the best approach to quality patient care.
Campbell
Christina Gayer
CG
Department of Health and Human Development, Montana State University, 20 Herrick Hall, Bozeman, MT 59717-3540, USA. ccampbel@montana.edu
Zander
Elin
E
Thorland
William
W
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000886:Anthropometry; D001835:Body Weight / Q000502:physiology*; D002153:Calorimetry, Indirect; D016638:Critical Illness; D004734:Energy Metabolism / Q000502:physiology*; D006760:Hospitalization; D006801:Humans; D008297:Male; D008875:Middle Aged; D009751:Nutritional Requirements; D011237:Predictive Value of Tests; D012189:Retrospective Studies; D013851:Thinness / Q000378:metabolism*