Monitoring Energy Metabolism with Indirect Calorimetry: Instruments, Interpretation, and Clinical Application

Abstract

Indirect calorimetry is the best measure to guide calorie administration during nutrition support. This article presents an update of the types of currently available indirect calorimeters and reviews the recent advances that guide the clinical application of indirect calorimetry. The emphasis of this report is placed on issues that the practicing clinician can use to evaluate, interpret, and apply measurements of energy expenditure.

A Systematic Review on Use of a Handheld Indirect Calorimeter to Assess Energy Needs in Adults and Children

“…The mean RQs provided were 0.71 ± .09 (27), 0.77 ± .06 (6), and 0.83 ± .01 (28). As noted by Holdy, "within the RQ range of 0.70 to 1.0 assuming a fixed RQ of 0.85, measuring only VO 2 may result up to a ± 4% error rate" (15). According to this assumption, the RQ results of Compher et al (6) and Reeves et al (27) should have been an overestimation of RMR using the Gem device compared with a metabolic cart.…”

“…Based on this information, a fixed RQ of 0.85 might not have resulted in the large measurement differences. Finally, An RQ of 0.85 is generally considered or expected to indicate appropriate energy provision in a patient on a mixed-fuel regimen (15). Therefore, the Gem's fixed RQ of 0.85 might result in a significant but nonmeaningful difference in RMR values.…”

Nutrition Assessment and Management of Left Ventricular Assist Device Patients

“…"Stress factors" as multipliers of REE in critically ill, ventilated patients is no longer recommended. 7,8 As the inflammatory response decreases and the patient becomes less ill, energy provisions can be advanced to meet total energy expenditure. Ambulatory and less severely ill patients need additional energy for activity and repletion in the range of 30 to 35 kcal/kg/day ( Table 2).…”

Study of the Metabolic Status by Complex Indirect Calorimetry and Bioimpedometry

“…It is also obvious that the criteria for correction of therapeutic rations in diabetics with type 2 disease and cardiovascular patients should be based on analysis of patients' metabolograms, body composition characteristics, and data of standard biochemical and hormone tests [2,4,8]. Final correction of therapeutic rations should be based on metabolograms at rest and metabolograms recorded under other physiological conditions, including exercise and test meals.…”