Validity of a Low-Flow Pneumotach and Portable Metabolic Measurement System

ABSTRACT

The purpose of this study was to investigate the validity of the MedGraphics VO2000 portable metabolic measurement system coupled with a low-flow pneumotach for the determination of oxygen consumption (VO2), carbon dioxide production (VCO2), and minute ventilation (VE) at rest. Twenty-four (12 male/12 female) young (23±5 y), healthy participants volunteered for this study. Mean height and weight were 173.9 cm (±10.5) and 74.3 kg (±11), respectively. Participants reported to the laboratory between the hours of 0700 and 1000 following a 12-h fast. A MedGraphics VO2000 portable metabolic measurement system equipped with a low-flow pneumotach was arranged in series to a Pre- Vent pneumotach for the MedGraphics CPX/D metabolic system. Participants rested in a supine position for a 20-min period of acclimation. Inspired and expired gases were collected for 60-min, after the acclimation period, for the analysis of VO2, VCO2, and VE. There were no significant difference (P<0.05) between the systems for VO2 (P=0.12), VCO2 (P=0.45), or VE (P=0.10). There were significant (P<0.05) correlation coefficients between the systems for VO2 (r=0.79), VCO2 (r=0.62), or VE (r=0.68). Bland-Altman plots indicated a good agreement between the two systems for VO2, VCO2 and VE. Results of this study indicated the MedGraphics VO2000 fitted with a low-flow pneumotach provides a valid metabolic measurement system for the measurement of resting metabolic rate.