Nine Current Problems in the Theory of Electrolyte and Water Balance

The paper reviews the 'classical theory' of fluid and electrolyte balance and then proceeds to list nine important problems implied by the theory for current modeling practice in electrolyte and water balance. The classical theory holds that functional fluid compartments of the body may be regarded, somewhat arbitrarily but conveniently, as homogeneous subdivisions of the body, each separated from the other by a membrane. Thus, we have the plasma, interstitial, intracellular, and transcellular compartments, and sometimes the 'red cell' compartment, the intraperitoneal, and others. Between any two compartments certain physical, chemical, and usually electrical phenomena are evident which alone cause the distribution of electrolytes and fluids which are observed empirically to exist.