Comparison of the effects of intravenous administration of isotonic and hypertonic sodium bicarbonate solutions on venous acid-base status in dehydrated calves with strong ion acidosis

Objective-To compare the effects of IV administration of isotonic (1.3%) and hypertonic (8.4%) sodium bicarbonate (NaHCO3) solutions on acid-base status in dehydrated calves with strong ion (metabolic) acidosis. Design-Randomized controlled clinical trial. Animals-50 calves with diarrhea and severe dehydration. Procedures-Calves were randomly assigned to receive isotonic NaHCO3 solution (65 mL/kg [29.5 mL/Ib], IV) over 3 hours (n = 30) or hypertonic NaHCO3 solution (10 mL/kg [4.5 mL/Ib], IV) over 20 minutes (20). Blood samples were collected at 0 hours (immediately prior to solution administration) and at 0.5, 1, 2, and 4 hours after administration began. Samples were submitted for blood gas analysis, serum biochemical analysis, and determination of blood Na+, K+, and Cl- concentrations and percentage change in plasma volume. Results Calves that received isotonic NaHCO3 solution had an increase in venous blood pH, HCO3 concentration, and base excess; a small, transient increase in PO2; and no change in PCO2 within 4 hours after administration began. Calves that received hypertonic NaHCO3 solution had an immediate increase in venous blood pH, HCO3 concentration, and base excess; a small, transient increase PCO2; and no change in PO2 within 0.5 hours after treatment began. Plasma volume increased to a greater extent following administration of isotonic solution than after administration of hypertonic solution. Conclusions and Clinical Relevance-IV administration of 8.4% NaHCO3 solution in small volumes provided fast and effective improvement of severe acid-base abnormalities in calves with severe strong ion acidosis but did not improve hydration status as well as administration of a larger volume of isotonic NaHCO3 solution. (J Am Vet Med Assoc 2010;236:1098-1103)