Body fluids and electrolytes after prolonged cardiopulmonary bypass

¹ Departments of Physiology and Pediatrics, Emory University, Atlanta, Georgia

Fluid and electrolyte balance was studied in 21 dogs after partial heart-lung bypass of 10 hr duration. Water retention was demonstrated by an increase in body weight and total body water, primarily due to an increase in extracellular fluid. Electrolyte retention was suggested by an increase in total extracellular sodium, potassium, and chloride. Urinary output was relatively normal but a progressive drop in urinary specific gravity was observed during bypass. Blood pH remained essentially unchanged. However, an increase in plasma lactate and a decrease in plasma bicarbonate suggested some degree of hypoxia and metabolic acidosis at the cellular level. Altered hormonal regulation of sodium and water excretion, hemolysis secondary to blood trauma, and the exchange of intracellular potassium for extracellular hydrogen ions were considered possible explanation for the fluid and electrolyte changes observed.

Submitted on June 20, 1963