The Measurement of Uptake of Nitrous Oxide by Pneumotachography. I. Apparatus, Methods and Accuracy.

A method of measuring the breath-by-breath uptake of nitrous oxide by the pulmonary capillary blood is described. With defined reservations, this uptake is given by the difference between the tidal volumes inspired and expired. The tidal volumes were measured by pneumotachography. The accuracy of these measurements is discussed. Precautions taken to reduce errors are described, with particular reference to the control of the temperature of respired gases; to the allowance for changes in the composition of expired gases; and to the reduction of electronic drift.