EE: Duration of Measurement (Steady State) (2013)

EE: Duration of Measurement (Steady State) (2013)

• Assessment
  How long should the duration of the RMR measurement be (related to steady state conditions) to ensure accuracy in the critically ill population?

  • Conclusion

    In critically ill patients, after discarding the data for the first five minutes to exclude artifact, achieving five additional minutes of measurement with 5% or less coefficient of variation (CV) in VO₂ and VCO₂ was comparable to 25 additional minutes of measurement with 10% or less CV.
    

     

     

     

  • Grade: I
    • Grade I means there is Good/Strong evidence supporting the statement;
    • Grade II is Fair;
    • Grade III is Limited/Weak;
    • Grade IV is Expert Opinion Only;
    • Grade V is Not Assignable.
    • High (A) means we are very confident that the true effect lies close to that of the estimate of the effect;
    • Moderate (B) means we are moderately confident in the effect estimate;
    • Low (C) means our confidence in the effect estimate is limited;
    • Very Low (D) means we have very little confidence in the effect estimate.
    • Ungraded means a grade is not assignable.
  • Evidence Summary: How long should the duration of the RMR measurement be (related to steady state conditions) to ensure accuracy in the critically ill population?
    • Detail
  • Search Plan and Results: EE: Duration of Measurement and Steady State in Critically Ill Individuals 2012
     
  If steady state cannot be achieved, how long should the duration of an indirect calorimetry measurement be to ensure accuracy in the critically ill population?

  • Conclusion

    In individuals unable to achieve steady state, a single indirect calorimetry measurement extended for up to two hours may reflect 24-hour total energy expenditure (TEE) with acceptable error. In addition, averaging two non-consecutive indirect calorimetry measurements within a 24-hour period provides sufficient accuracy for estimation of TEE.

     

  • Grade: II
    • Grade I means there is Good/Strong evidence supporting the statement;
    • Grade II is Fair;
    • Grade III is Limited/Weak;
    • Grade IV is Expert Opinion Only;
    • Grade V is Not Assignable.
    • High (A) means we are very confident that the true effect lies close to that of the estimate of the effect;
    • Moderate (B) means we are moderately confident in the effect estimate;
    • Low (C) means our confidence in the effect estimate is limited;
    • Very Low (D) means we have very little confidence in the effect estimate.
    • Ungraded means a grade is not assignable.
  • Evidence Summary: If steady state cannot be achieved, how long should the duration of an indirect calorimetry measurement be to ensure accuracy in the critically ill population?
    • Detail
    • Quality Rating Summary
      For a summary of the Quality Rating results, click here.
    • Worksheets
      • McClave SA, Spain DA, Skolnick JL, Lowen CC, Kieber MJ, Wickerham PS, Vogt JR, Looney SW. Achievement of steady state optimizes results when performing indirect calorimetry. JPEN J Parenter Enteral Nutr. 2003; 27(1): 16-20.
      • van Lanschot JJ, Feenstra BW, Vermeij CG, Bruining HA. Calculation versus measurement of total energy expenditure. Critical Care Medicine. 1986; 14: 981-985.
      • Zijlstra N, ten Dam SM, Hulshof PJ, Ram C, Hiemstra G, de Roos NM. 24-hour indirect calorimetry in mechanically ventilated critically ill patients. Nutr Clin Pract. 2007; 22(2): 250-255.
  • Search Plan and Results: EE: Duration of Measurement and Steady State in Critically Ill Individuals 2012