Does achievement of steady state optimize results when performing indirect calorimetry?
These data support the use of steady state, best defined as an interval of 5 consecutive minutes whereby VO2 and VCO2 change by <10%. The mean REE from this period correlates best to the 24-hour TEE regardless of CV. IC testing can be completed after achievement of steady state. Activity factors of 10% to 15% should not be added to the steady-state REE, because this practice significantly decreases the accuracy. In patients who fail to achieve steady state, the CV helps to determine the appropriate duration of IC testing. In those patients with a low CV (< or = 9.0), 30-minute test duration is adequate. In patients with CV >9.0, test duration of at least 60 minutes may be required. These latter patients should be considered for 24-hour IC testing.
Thus, our data support the presence of a saturable and active transporter of leptin from circulation into intrathecal space.