Abstract
Background: The assessment of resting energy expenditure (REE) through indirect calorimetry (IC) in patients that require oxygen or non-invasive ventilation (NIV) may provide erroneous values due to gas mixture instability of the supplementary oxygen and NIV gas leakage.
Purpose and Objectives: To validate a new REE measurement method using an indirect calorimeter in healthy subjects undergoing NIV at a FiO2 of 0.21 and 0.3 (new method) comparing their REE values with those breathing spontaneously (SB) at a FiO2 of 0.21 (reference method).
Methods: Prospective, observational, agreement study.
We measured REE of healthy volunteers in three different settings: a) SB-FiO2 0.21, b) NIV-FiO20.21 and c) NIV-FiO2 0.30.
Results: We analyzed 56 volunteers: 29 women (52%), mean age 31 years old, mean body mass index of 24.2kg/m2.
We found an adequate agreement among REE measurement with NIV-FiO2 0.21, NIV FiO2 0.3 and SB-FiO2 0.21.
The average difference between NIV-FiO2 0.21 and NIV FiO2 0.3 was 60kcal (IC 95% 15.9 to 104); between NIV-FiO2 0.21 and SB-FiO2 0.21, 117kcal (IC 95% 79to 155); and between NIV FiO2 0.3 and SB-FiO2 0.21, 57kcal (0.8 to 113).
Measurement errors were similar among different ranges of REE. We found a slight tendency towards over-estimation of REE without clinical significance.
Conclusions: REE measurement with IC using NIV at different Fi02 concentrations proved an adequate agreement with REE measurements in SB subjects.
These new method will allow the use of IC to measure REE in patients with supplementary oxygen and/or NIV needs.
- Copyright ©ERS 2015