Common electrolyte changes during and after resuscitation in a patient with a burn of 65% of the total body surface include:

A. A serum sodium concentration of 128 mEq. per liter following 48 hours of resuscitation fluid therapy

B. A serum sodium concentration of 152 mEq. per liter on the fifth postburn day in a 75-kg. male with a 75% burn who has received only calculated maintenance fluids each day following successful resuscitation.

C. A serum potassium concentration of 5.7 mEq. per liter as a consequence of the destruction of red cells and other tissues in a patient with high-voltage electrical injury.

DISCUSSION: At the end of the first 48 hours of resuscitation, when lactated Ringer's solution is used in the first 24 hours and colloid-containing fluid and electrolyte-free fluid in the second 24 hours, modest hyponatremia (serum sodium concentration of 128 to 130 mEq. per liter) is commonly observed but requires no treatment. The total body salt load is actually increased, and appropriate fluid management permits the increased evaporative water loss to correct that imbalance. The most common postresuscitation fluid and electrolyte disturbance is hypernatremia associated with dehydration due to inadequate replacement of insensible water loss. The hourly insensible water loss, which far exceeds maintenance fluid requirements in uninjured patients, can be calculated thus:  

Insensible water loss (in ml./hr.)=(25 + % of body surface burned) × total body surface area (sq. m.) The release of potassium from red cells and other tissues injured by the burn or by electrical current can cause usually modest hyperkalemia. If acidosis occurs, the hyperkalemia may be exaggerated to symptomatic levels that require treatment. Hypokalemia can be induced following resuscitation by the kaliuretic effect of sulfamylon burn cream, but the hypokalemia associated with 0.5% silver nitrate soak treatment is due to transeschar leaching of potassium. Hypocalcemia is frequently associated with hypoalbuminemia as a consequence of hemodilution by the resuscitation fluid and the cytokine-induced reprogramming of hepatic protein synthesis. In such cases ionized calcium levels are commonly normal.