Some circulatory aspects of the oxygen transport in patients with emphysema.

67 patients were studied by pulmonary function and heart catheterization at rest, during exercise and after 20 min 100% oxygen breathing. 14 patients were diagnosed as having COLD without chronic respiratory insufficiency (CRI). 45 patients were considered to be suffering from pulmonary emphysema (COLD + CRI). In this group, 23 patients had normal hemoglobin concentrations (CHb), 14 patients demonstrated decreased values and 8 had secondary polycythemia. All groups of patients had a normal cardiac output (CO), oxygen consumption (VO2) and pulmonary wedge pressure (Pw) at rest and after oxygen breathing. In the group with COLD and CRI high values for pulmonary vascular resistance (Rp) were found, most pronounced in those with polycythemia. All groups of patients except the polycythemia group demonstrated a significant decrease of Rp during oxygen breathing, but only a slight decrease of pulmonary arterial pressure (Ppa). It can be concluded that a normal quantity of oxygen transport to peripheral tissues in patients with arterial hypoxemia can be achieved by maintaining normal values for arterial mixed venous oxygen content without a shift of the oxygen dissociation curve.