Pediatric patients may experience fluid loss and dehydration in a number of ways. The gastrointestinal tract represents one of the most significant sources of water and electrolyte losses that can result in dehydration and electrolyte imbalance. Accompanying these fluid and electrolyte losses are resulting acid–base disturbances that occur through bicarbonate loss in the stool or acid losses through vomiting.

There are several sources of electrolyte imbalance that occur through the loss of body fluids. Table 146.1 provides the electrolyte concentrations for common gastrointestinal secretions. Being mindful of these electrolyte concentrations can assist providers in appropriately selecting replacement fluids and replenishing deficits.

To correct electrolyte imbalances caused by sodium, potassium, and chloride losses in stool and urine, maintenance fluids are frequently selected to augment the body’s homeostatic mechanisms and compensate for the electrolyte imbalance. The general maintenance requirements for sodium are 2 to 3 mEq/kg/24 hour and the requirement for potassium is 1 to 2 mEq/kg/ 24 hour. As long as at least half of these elements are bound as a chloride salt, the chloride requirements will automatically be satisfied due when disassociation of the ions occurs. Most commercially available intravenous solutions are adequate for replacement and are much less expensive and error-prone than customized solutions. Table 146.2 provides the electrolyte profiles for commonly available intravenous solutions.