Methods for the clinical measurement of oxygen uptake and carbon dioxide production

Clinical methods using feedback for the respiratory measurement of oxygen uptake (?VO2) in neonates and for the measurement of both oxygen uptake and carbon dioxide production (?VCO2) in adults have been developed. Instruments which use these methods to measure ?VO2 and ?VCO2 have been constructed. The prototype adult ?VO2 measurement device was determined to have an accuracy of ±2.3 percent in laboratory tests and 5.9 percent in human volunteer studies. The neonatal ?VO2 measurement prototype, using room air as an inspired gas, showed accuracies of ±2.4, ±2.8, and ±7.3 percent of full scale in theoretical, bench, and animal experiments, respectively. The adult ?VO2 and ?VCO2 measurement system computes total metabolism and the fractional contribution of fat, protein, and carbohydrate to the total metabolism from ?VO2 and ?VCO2, and laboratory values of nitrogen excretion. The device was demonstrated to have a measurement accuracy for ?VCO2 of ±4.1 percent of full scale in bench studies.