2000s, Basal metabolism, Douglas Bag, Oxygen Consumption Douglas Bag, Oxygen Consumption, 2007 October 24, 2016 Richard Johnston Leave a comment A Douglas Bag is used to collect exhaled air in order to measure oxygen consumption. From “Indirect Calorimetry: A Practical Guide for Clinicians”, Nutrition in Clinical Practice, 2007, 22(4): 277-388.