[Water-electrolyte and acid-base balance in surgery. Problems in the postoperative period]

In addition to metabolic conditions, water-electrolyte and acid-base balance in the postoperative period are of major importance for the success of surgery. The principal water-electrolyte changes (hyperhydration and hypotonic dehydration, hypertonic dehydration, "third space" syndrome, etc.) and acid-base (acidosis, and metabolic and respiratory alkalosis) disorders are briefly described as they are observed in the postoperative period together with their pathophysiologic mechanisms and therapy. The identification and correction of these changes may avoid the onset of patterns due to reduced therapeutic surveillance.