The prevention of the fluid-electrolyte "problem" by simple means.

Proper fluid balance may be maintained in patients after operation by the employment of simple, inexpensive procedures which may be carried out even in the smallest hospitals. Daily weighing of patients, measurement of fluid intake and output, and knowledge of the probable electrolyte content of fluid losses are adequate guides for replacement of fluids and electrolytes. An increase in body weight is a warning of overhydration.The content of the solution used for replacement is dictated by the route of fluid output-whether from the gastrointestinal tract, the skin, or the kidneys. Insensible losses (by perspiration and respiration) are fairly static. Except to replace extrarenal losses, parenteral administration of normal saline solution in the immediate postoperative period is contraindicated. Mistakes in replacement methods, especially those causing overhydration, are particularly hazardous for elderly patients.