Care of Client With Fluids and Electrolytes Imbalance (Process of Movement Across The Membranes)

1. MECHANISMS CONTROLLING FLUID AND ELECTROLYTE MOVEMENT

Many different processes are involved in the movement of electrolytes and water between the ICF and ECF. Some of the processes include simple diffusion, facilitated diffusion, and active transport. Water moves as driven by two forces: hydrostatic pressure and osmotic pressure.

Osmotic pressure is the amount of pressure required to stop the osmotic flow of water. In the metabolically active cell, there is a constant exchange of substances between the cell and the interstitium, but no net gain or loss of water occurs.

Measuring osmolality is important because it indicates the water balance of the body. Osmolality indicates the concentration of all the particles dissolved in body fluid. It is routinely measured in clinical laboratories for the differential diagnosis of disorders related to the hydrolytic balance regulation, renal function, and small-molecule poisonings.

Hydrostatic pressure is the force within a fluid compartment and is the major force that pushes water out of the vascular system at the capillary level.

Oncotic pressure (colloidal osmotic pressure) is osmotic pressure exerted by colloids in solution. The major colloid in the vascular system contributing to the total osmotic pressure is protein.