Basic rules of parenteral fluid therapy.

The following basic rules of parenteral fluid therapy are formulated with the aim of alleviating concern and confusion about i.v. fluid orders that are experienced by most physicians: Don't be generous with fluid; in determining the water intake, one must know the usual water output through the kidney, skin and lung; one must know the quantities of the electrolytes and nutrients that are being given, and know the initial volume of distribution (usually the ECF); one must know the aim of fluid therapy; one must not give and remove the same substance at the same time; one must be aware that hypertonic saline contains less water for a given amount of Na than isotonic saline; one must be familiar with different i.v. solutions and i.v. additives; one must be aware that the kidney does not manufacture water or electrolytes except for bicarbonate; for short-term fluid therapy, divalent ions (Ca, Mg, and P) do not need replacement; one should think about COP-wedge gradient in determining the type of fluid to be given.