Abstract: Objective: From the point of holistic integrative medicine,the D_LCO depends on not only normal respiratory and circulatory functions, but also an optional matching between them. However, due to the limitation of traditional systemic physiology, the D_LCO always be classified as lung functional parameter to be analyzed and interpreted. Because ignoring the circulatory system function, so it will certainly have some misunderstandings. Methods: Based on the Holistic Integrative Medicine, under the control of neurohumoral, respiratory, circulatory and metabolic systems work together, we discussed the diffusion function. We analyzed the change of D_LCO in the patients with cardiac dysfunction, especially the heart failure. Results: The D_LCO, CO gas diffusion from lung circulating blood, depends on the normality of respiratory and circulatory systems and their matching.We analyzed the reasons of D_LCO for characteristic pathophysiological changes of patients with heart failure. Conclusion: The normal D_LCO depends on a good matching of normal respiratory and circulatory systems. For heart failure, the respiratory and circulatory systems matching is poor. Due to dominant limitation of left ventricle pump function, pulmonary blood volume may slightly increased, but combination of all reduced pulmonary blood flow rate, thicked diffuse member and increased diffusion distance etc. suggest that patients with heart failure should have a decreased, rather than increased, D_LCO.

Key words: diffusing capacity of gas, lung function, holistic integrative physiology, respiratory, circulation, metablism