Bronchospirometric studies of lung volumes, ventilation/perfusion ratios and diffusion

¹ Department of Medicine, University of Wisconsin Medical School, and Veterans Administration Hospital, Madison, Wisconsin

Bilateral bronchospirometric nitrogen washout studies were used for the first time to calculate ventilation/perfusion ratios for the well and poorly ventilated areas in individual lungs. Results were compared with washout studies on both lungs measured together. Data suitable for analysis were obtained from seven patients with chronic lung disease. It was demonstrated that this technique for determining simultaneous ventilation/perfusion ratios for each lung gave accurate and detailed physiological changes. Comparison of the sum of average values for pulmonary capillary blood flow when both lungs were measured together by the same nitrogen washout technique showed a variation within the accepted 10% error for cardiac output. Diffusion for the separate lungs, measured by the carbon monoxide breath-holding method, gave values which correlated with lung volumes.

Submitted on November 22, 1963