Pulmonary Lymph

Abstract

Summary

Po₂ in right lymph duct of 15 anesthetized dogs averaged the same as in arterial blood (75 ± 18 mm Hg); Po₂ in thoracic duct lymph was close to that in mixed-venous blood (34 ± 20 mm Hg). Allowing for admixture of systemic lymph in the right duct, Po₂ in lymph from the respiratory portion of the lung must fall between alveolar gas and arterial blood. The marked difference from thoracic duct lymph P0₂ (p<.001) supports the concept of lymph as a useful measure of Po₂ in interstitial fluid and tissues. Use of mixing equations shows that during air breathing respiratory (i.e., gas-exchanging) tissues contributed at least 53% of right duct lymph flow.