Energy Expenditure

EE: Executive Summary of Recommendations (2013)

Executive Summary of Recommendations

Below are the major recommendations and ratings for the Academy of Nutrition and Dietetics Evidence-Based Nutrition Practice Guideline for Measuring Resting Metabolic Rate (RMR) in the Critically Ill. Click here to view the Guideline Overview. More detail (including the evidence analysis supporting these recommendations) is available on this website to Academy members and EAL subscribers under Major Recommendations.

To see a description of the Academy's Recommendation Rating Scheme (Strong, Fair, Weak, Consensus, Insufficient Evidence), click here.

The Recommendations are listed below. [Note: If you mouse-over underlined acronyms and terms, a definition will pop up.]

  • Nutrition Assessment
    EE: Thermic Effect of Continuous Feeding in Critically Ill
    Whether or not a critically ill patient is receiving continuous infusion of an energy source (e.g., energy-containing intravenous fluids or medications, enteral nutrition or parenteral nutrition), the registered dietitian nutritionist (RDN) may proceed with the indirect calorimetry measurement. Based on limited evidence comparing continuous feeding to fasting, the presence of a thermic effect of continuous feeding (TEF) is inconclusive. Waiting for infusion of an energy source or holding continuous feedings before conducting a measurement of resting metabolic rate (RMR), may not be necessary.
    Weak
    Conditional
    EE: Thermic Effect of Bolus or Intermittent Feeding in Critically Ill
    Following a bolus or intermittent feeding in the critically ill patient, the RDN should wait at least four hours to do an indirect calorimetry measurement. Delaying the indirect calorimetry measurement is recommended, because of the potential TEF during the post-absorptive state.
    Consensus
    Conditional
    EE: Diurnal Variation in Critically Ill
    If the critically ill patient is mechanically ventilated and receiving continuous feedings, then the registered dietitian nutritionist (RDN) may conduct a measurement of resting metabolic rate (RMR) at any time of day, as long as resting conditions can be achieved. Likewise, if a measurement of total energy expenditure (TEE) is being considered, time of day does not need to be taken into account. Research indicates that there is no significant diurnal variation in either RMR or TEE in mechanically ventilated patients receiving continuous feedings. The effect of diurnal variation in critically ill patients who are not mechanically ventilated while receiving continuous feedings is unknown.
    Fair
    Conditional
    EE: Gas Collection Devices in Critically Ill
    If the critically ill patient is spontaneously breathing (not intubated or receiving supplemental oxygen), the registered dietitian nutritionist (RDN) should consider the canopy or hood to conduct a resting metabolic rate (RMR) measurement. Typically, the canopy or hood is reasonably tolerated by the patient, fits most patient circumstances and is most likely to produce a complete gas collection. However, patient circumstances or preference may require use of an alternative gas collection device.
    Consensus
    Conditional
    EE: Room Conditions for Measuring RMR in Critically Ill Patients
    The registered dietitian nutritionist (RDN) should ensure resting metabolic rate (RMR) is measured in a quiet, thermoneutral environment for the critically ill population. Cool room temperatures or drafts may generate shivering and nonshivering thermogenesis. Research is needed to define the range of thermoneutrality for the critically ill population.
    Consensus
    Imperative
    EE: RMR Measurements in the Usual Body Position in Critically Ill
    The registered dietitian nutritionist (RDN) should conduct indirect calorimetry measurements in the critically ill patient who is in the semi-recumbent posture (standard position in the ICU). However, it is acceptable to measure the patient in the non-semi-recumbent position, if that is their usual body position. Limited research reports that posture can affect the accuracy of the measurement of resting metabolic rate (RMR) in some critically ill patients. 
    Fair
    Imperative
    EE: RMR Measurements After Changes in Usual Body Position in Critically Ill
    In critically ill patients, if the patient's usual body position changes temporarily, the RDN should wait until the patient is moved back into the usual body position in order to perform indirect calorimetry. If the patient's usual body position changes to a new permanent position (e.g., change in head of bed elevation), the RDN should conduct a new indirect calorimetry measurement. See Rest Period Duration for Measuring RMR. Limited research reports that posture can affect the accuracy of the measurement of resting metabolic rate (RMR) in some critically ill patients.
    Fair
    Conditional
    EE: Rest Period Duration in Critically Ill
    The registered dietitian nutritionist (RDN) should ensure a 30-minute rest period prior to resting metabolic rate (RMR) measurement in critically ill patients. One study indicates that energy expenditure is elevated for up to 30 minutes after routine intensive care unit (ICU) care in non-sedated patients. The potential for sedation to shorten the rest period has not been studied. 
    Fair
    Imperative
    EE: Duration of Measurement Related to Steady State in Critically Ill
    When measuring energy expenditure in a critically ill patient, the registered dietitian nutritionist (RDN) should discard the data for the first five minutes to exclude artifact and then achieve either a five-minute measure with up to 5% or a 25-minute measurement with up to 10% coefficient of variation (CV) in VO2 and VCO2. Research indicates that these protocols are equivalent.
    Strong
    Imperative
    EE: Measurement Duration If Unable to Achieve Steady State in Critically Ill
    If unable to achieve steady state in critically ill patients, the RDN should take a single indirect calorimetry measurement extended for up to two hours or average two non-consecutive indirect calorimetry measurements within a 24-hour period. Research suggests that this protocol likely reflects 24-hour total energy expenditure (TEE) with acceptable error.
    Fair
    Conditional
    EE: RQ Within the Physiologic Range in Critically Ill
    If the respiratory quotient (RQ) falls within the physiologic range (0.67 to 1.3) the registered dietitian nutritionist (RDN) should not use RQ alone to reject the resting metabolic rate (RMR) measurement. Research shows that RQ can be manipulated within the physiologic range by changing respiratory parameters without altering the RMR measurement.
    Fair
    Imperative
    EE: RQ Outside the Physiologic Range in Critically Ill
    If the RQ falls outside the physiologic range (below 0.67 or greater than 1.3), the RDN should suspect an error and repeat the RMR measurement. The physiologic range of RQ reflecting cellular metabolism is 0.67 to 1.3. Values for RQ outside of this range indicate an inaccurate RMR measurement.
    Consensus
    Conditional
    EE: Limitations of RQ in Evaluating Feeding Levels in Critically Ill
    The RDN should not rely solely on measured RQ to evaluate level or composition of feeding. Research demonstrates that RQ has poor accuracy to evaluate under- and over-feeding. RQ can vary among individuals at any given feeding level and can be altered by factors unrelated to feeding.
    Strong
    Imperative