Validation of whole room indirect calorimeters: refinement of current methodologies

摘要

Whole room indirect calorimeter (WRIC) validation techniques consist of propane combustion (PC) or infusion of mixed carbon dioxide (CO 2 ) and nitrogen (N 2 ) by a precision blender (PB). To determine the best method, PC of 6, 10, 22?￠????h and PB infusions of 6, 10, and 14?￠????h, were conducted. The 14?￠????h infusion consisted of two metabolic settings. Energy expenditure (EE; kJ), ventilation (V; liters/min) of oxygen (VO 2 ), VCO 2 , and respiratory quotient (VCO 2 /VO 2 ) obtained from the WRIC were extrapolated to the respective test durations and compared to similarly calculated values. Moreover, accurate equations (AE) were derived to correct infusions for additional N 2 . As a final evaluation of a PC validated WRIC, weight maintenance (WM), energy balance (EB), respiratory quotient (RQ), and food quotients (FQ) were determined in 22 subjects who had repeat 24?￠????h EE measurements. Statistical analyses ( P ????