Potassium chloride is a major cation of the intracellular fluid. It plays an active role in the conduction of nerve impulses in the heart, brain and skeletal muscle; contraction of cardiac skeletal and smooth muscles; maintenance of normal renal function, acid-base balance, carbohydrate metabolism and gastric secretion.
Sodium chloride is the major extracellular cation. It is important in electrolyte and fluid balance, osmotic pressure control and water distribution as it restores sodium ions. It is used as a source of electrolytes and water for hydration, treatment of metabolic acidosis, priming solution in haemodialysis and treatment of hyperosmolar diabetes.
It is also used as diluents for infusion of compatible drug additives.
Dextrose is a monosaccharide that is used as a source of calories and water for hydration. It helps to reduce loss of body protein and nitrogen. It also promotes glycogen deposition in the liver. When used with insulin, it stimulates the uptake of potassium by cells, especially in muscle tissue, thus lowering serum potassium levels.
Sodium bicarbonate raises blood and urinary pH by dissociation to provide bicarbonate ions, which neutralises the hydrogen ion concentration. It also neutralises gastric acid via production of carbon dioxide.