THEORETICAL ANALYSIS OF THE MEASUREMENT OF LUNG TISSUE VOLUME BY REBREATHING AND ITS APPLICATION TO THE MEASUREMENT OF RE3PEATHIXG DEAD SPACE

摘要

Fast responding mass spectrometers are now available chat can continuously monitor respiratory gases during rebreathing. These measurements permit rapid, non-invasive determinations of pulmonary tissue volume (Vt) and pulmonary capillary blood flow (Qc ). The factors that may influence these measurements have not been studied in detail.nWe used a mathematical model to study the effect of various forms of uneven distribution on rebreathing measure¬ments of Vt and Qc . Dimensions of the model were:rebreathing rate of 30 breaths per minute, residual volume (RV) of 2 L, Vt = 600 ml, Qv =6 L/minute, and Bunsen solubility coefficient of 9 ml/ml/atmosphere for dimethyl ether.