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Acta Phlebologica 2013 August;14(2):49-52

Copyright © 2013 EDIZIONI MINERVA MEDICA

language: English

Starling’s law and viscosity

Allegra C.

Director of the Masters Program in Vascular Diseases, Azienda Ospedaliera S. Giovanni-Addolorata, Rome, Italy

The author examines Starling’s equation and its revision as primarily proposed by Adamson and Levick who raised the problem of “the area under the protection of the glycocalyx” and of reabsorption of proteins from tissue fluid, which thereby deprived the equation originally based on two elements, oncotic pressure and capillary-interstitial hydrostatic pressure, of its conceptual simplicity. Drawing on his in vivo studies of skin microcirculation and dynamic capillaroscopy, the author focuses on the determinant role of initial lymphatics anchored in the tissue, dependent on tissue pressure, and on the phenomenon of arteriolar vasomotion which causes variations in capillary hematocrit and subsequently in oncotic and hydrostatic pressure. In vivo studies with the use of direct measurement in humans may offer the key to the debate on Starling’s equation. The problem of capillary fissures and the glycocalyx remains open, however. What can be concluded for the moment is that, because it is didactically useful, the original equation should be maintained, and to continue to explore the capillary bed in vivo and direct more attention to the microcirculation in lymphatic tissue.