Pulsing reverse osmosis as the mechanism underlying fluid exchange

Problems inherent in the existing theories of fluid exchange are discussed. An alternative theory based on the interaction between the pulsing of the capillary pressure and the osmotic gradient between plasma and interstitial fluid is offered. Theoretic values for plasma and interstitial osmolalities are calculated. These are similar to the pressure found in the Bowman's capsule in the kidney. The theory offers a possible explanation for the pulsatile nature of the blood pressure, the formation of oedema and the stasis of fluid exchange in shock.