Simple Methods of Estimating Oxygen Consumption and Efficiency of the Muscles of Breathing

The oxygen consumption of the respiratory muscles can be estimated by increasing the ventilation with added dead space and by measuring oxygen consumption and ventilation utilizing a closed circuit spirometer. By inspiring through an external resistance known amounts of extra mechanical work can be imposed on the respiratory muscles. The efficiency of the respiratory muscles can be estimated by measuring the increased oxygen consumption associated with the performance of the added respiratory work. The applicability and errors of the methods are illustrated with data obtained from a normal subject and a patient with emphysema. Submitted on January 14, 1957