DETERMINATION OF PULMONARY BLOOD-FLOW BY THE REBREATHING TECHNIQUE IN AIR-FLOW OBSTRUCTION

Publisher Website
Google Scholar
Abstract
To test the hypothesis that the effect of nonuniform gas distribution on the uptake of inhaled soluble gases in the lung is minimized by rebreathing, pulmonary blood flow was measured by the thermodilution technique, and pulmonary capillary blood flow, combined pulmonary tissue and capillary blood volume, diffusing capacity of the lung for CO and alveolar volume, by a rebreathing technique in conscious sheep before and immediately after inhalation of a histamine aerosol (4% solution). Pulmonary resistance, distribution of ventilation by multiple breath N2 washout and arterial blood gases were measured to monitor airway responses. Histamine inhalation produced a mean pulmonary resistance increase to 621% of baseline accompanied by uneven distribution of ventilation and a decrease in arterial pO2 [O2 pressure]. Despite these alterations in airway function, there were no concomitant changes in pulmonary capillary blood flow, combined pulmonary tissue and capillary blood volume, diffusing capacity of the lung for CO, alveolar volume or the ratio of diffusing capacity for CO to alveolar volume. Mean pulmonary capillary blood flow and pulmonary blood flow did not differ from each other before and after histamine inhalation. The rebreathing technique for noninvasive measurement of pulmonary hemodynamics is satisfactory in the presence of airflow obstruction.

This publication has 2 references indexed in Scilit: