Effects of Alkalinization and Rehydration on Plasma Potassium Concentrations in Neonatal Calves with Diarrhea

BACKGROUND Increased plasma potassium concentrations (K(+)) in neonatal calves with diarrhea are associated with acidemia and severe clinical dehydration and are therefore usually corrected by intravenous administration of fluids containing sodium bicarbonate. OBJECTIVES To identify clinical and laboratory variables that are associated with changes of plasma K(+) during the course of treatment and to document the plasma potassium-lowering effect of hypertonic (8.4%) sodium bicarbonate solutions. ANIMALS Seventy-one neonatal diarrheic calves. METHODS Prospective cohort study. Calves were treated according to a clinical protocol using an oral electrolyte solution and commercially available packages of 8.4% sodium bicarbonate (250-750 mmol), 0.9% saline (5-10 L), and 40% dextrose (0.5 L) infusion solutions. RESULTS Infusions with 8.4% sodium bicarbonate solutions in an amount of 250-750 mmol had an immediate and sustained plasma potassium-lowering effect. One hour after the end of such infusions or the start of a sodium bicarbonate containing constant drip infusion, changes of plasma K(+) were most closely correlated to changes of venous blood pH, plasma sodium concentrations and plasma volume (r = -0.73, -0.57, -0.53; P < .001). Changes of plasma K(+) during the subsequent 23 hours were associated with changes of venous blood pH, clinical hydration status (enophthalmos) and serum creatinine concentrations (r = -0.71, 0.63, 0.62; P < .001). CONCLUSIONS AND CLINICAL IMPORTANCE This study emphasizes the importance of alkalinization and the correction of dehydration in the treatment of hyperkalemia in neonatal calves with diarrhea.