Part II. A Portable Miniaturized Metabolic Gas Analysis System

Introduction Previously we proposed construction of a miniaturized metabolic monitor that could be taken aboard the space station to monitor the physiological response of the body in a microgravity environment. The prototype consisted of an on airway non-dispersive infrared (NDIR) CO2 sensor and a luminescencequenching O2 sensor to measure gas concentrations, and differential pressure ports to measure gas flows. Our motivations, prototype design considerations, and initial experiments were presented in a previous paper. 1 This paper aims to further examine the efficacy of the prototype device through 1) characterization of the flow profile by using a discharge coefficient, and 2) validation of the oxygen sensor at the high volumetric flows.