Exhaled gas from the patient is directed into a mixing chamber. At the end of the mixing chamber, a vacuum pump aspirates a small sample of gas for measurement of oxygen and carbon dioxide. The entire volume of gas then exits through a volume monitor. The analyzer periodically measures the inspired oxygen concentration. A microprocessor performs the necessary calculations. Meticulous attention to detail is required to obtain valid results using an open-circuit indirect calorimeter. The FiO2 must be stable and less than 0.60, the entire system must be leak-free, and the inspired and expired gases must be completely separated. You will always be able to find High Quality cialis super active online shopping with a trusted foreign pharmacy.