CI: Indirect calorimetry to determine RMR

Indirect calorimetry is the standard for determination of resting metabolic rate (RMR) in critically ill patients because RMR based on measurement is more accurate than estimation using predictive equations.

Rating: Strong

Imperative

CI: RMR Predictive equations for nonobese patients

If predictive equations are needed in nonobese, critically ill patients, consider using one of the following, as they have the best prediction accuracy of equations studied (listed in order of accuracy): Penn State, 2003a (79%), Swinamer (55%), and Ireton-Jones, 1992 (52%). In some individuals, errors between predicted and actual energy needs will result in under- or over-feeding.

Rating: Fair

Conditional

CI: Inappropriate RMR predictive equations for this population

The Harris-Benedict (with or without activity and stress factors), the Ireton-Jones, 1997, and the Fick equations should not be considered for use in RMR determination in critically ill patients, because these equations do not have adequate prediction accuracy. In addition, the Mifflin-St. Jeor equation should not be considered for use in critically ill patients, as it was developed for healthy people and has not been well researched in the critically ill population.

Rating: Strong

Imperative

CI: RMR predictive equations for obese patients

If predictive equations are needed for critically ill, mechanically ventilated individuals who are obese, consider using Ireton-Jones, 1992 or Penn State, 1998, because they have the best prediction accuracy of equations studied. In some individuals, errors between predicted and actual energy needs will result in under- or over-feeding.

Rating: Fair

Conditional

CI: Rest periods and RMR

Allow a rest of 30 minutes prior to RMR measurement in critically ill patients.

Rating: Consensus

Imperative

CI: Rest period and accuracy of RMR

If the critically ill patient has undergone a nursing activity or medical procedure (e.g., suctioning, wound care, central venous access or ventilator setting change), then employ a 30-minute rest after procedures to achieve a resting state during RMR measurement. Measuring RMR before the 30-minute period may be inaccurate because patient instability or ventilator gas re-equilibration.