Changes in Intrapulmonary Venous Admixture with Varying Inspired Oxygen Concentration in the Patients with Chronic Pulmonary Diseases : Comparison of Conventional and Corrected Values

Changes in intrapulmonary venous admixture (Q^^._S/Q^^._P ratio) with varying inspired oxygen concentration (F_1O_2) were discussed in 27 patients with chronic pulmonary diseases. Calculated Q^^._S/O^^._P ratio with conventional method increased during breathing with F_1O_2 above 0.6. However, little increase in corrected Q^^._S/Q^^._P ratio was proved. A difference between conventional and corrected values with F_1O_2 1.0 was nealy 9 percent of total pulmonary blood flow. Therefore, conventional Q^^._S/Q^^._P ratio may be overestimated and corrected values should be needed for discussion on changes in intrapulmonary venous admixture.