title: Mechanisms of Qi-blood circulation and Qi deficiency syndrome in view of blood and interstitial fluid circulation.
abstract: OBJECTIVE
  Based on comparison between fundamental theories of Traditional Chinese Medicine (TCM) and Western Medicine (WM) and modern scientific research on meridians, we find that "Qi" in TCM is closely related to tissue fluid. In this study, the essence of Qi is explored in the view of circulation of blood and interstitial fluid.
  
  
  METHODS
  Because the concept of Qi is complicated, Qi deficiency syndrome (QDS) is chosen to probe the relationship between of Qi deficiency and Qi-blood circulation (QBC). We analyze Qi-blood theory in terms of WM, set up a hemodynamic model to describe QBC, and review clinical research on QDS in the view of blood-interstitial fluid circulation.
  
  
  RESULTS
  QDS is caused by imbalances of substance exchanges between blood and interstitial fluid, leading to an increase in the interstitial liquid volume or a decrease and retention of metabolic wastes in interstitial fluid.
  
  
  CONCLUSIONS
  This study describes the essence of Qi, providing support for further research on theories of Qiand Qi-blood circulation in TCM.
authors.affiliation: Department of Mechanics and Engineering Science, Fudan University, Shanghai Research Center of Acupuncture, Shanghai 200433, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Yao
authors.forename: Hongwei
authors.initials: H
authors.lastname: Yang
authors.forename: Guanghong
authors.initials: G
authors.lastname: Ding
mesh_terms: D001775:Blood Circulation; D045604:Extracellular Fluid / Q000737:chemistry*; D006439:Hemodynamics; D006801:Humans; D007700:Kinetics; D008516:Medicine, Chinese Traditional; D019413:Qi