Towards point of care human energy expenditure measurement on a hand-held breath analyser

A newly developed low-cost, hand-held calorimeter is reported for the measurement of energy expenditure (EE) from human breath. The prototype device uses oxygen (low-power electrochemical) and carbon dioxide (low-power novel NDIR) sensors to calculate the energy burned over a given period. Knowledge of the energy required by the body is critical to healthcare applications (to ensure adequate feeding during recovery) and society (to halt the global trend towards an obese population). Reference measurements were taken inside a hospital respiratory room with the hand-held unit giving an error +2.4 %, an analyser with commercial sensors an error of +7.9 %, and calculated values (Harris Benedict) with an error of +41.4 %. Further work involves utilising the portability of the analyser to perform measurements outside of a hospital environment with a smartphone to display the EE information, and a detailed investigation of the volatile biomarkers in exhaled breath for the diagnosis of diseases and metabolism disorders.