Ability of intravenous small-volume hypertonic sodium bicarbonate, sodium chloride, and glucose solutions to rapidly reverse electrocardiographic abnormalities in hyperkalemic calves with neonatal diarrhea
Florian M Trefz, Ingrid Lorenz, Peter D ConstableAbstract
Background
Hyperkalemia is common in dehydrated calves with neonatal diarrhea and can result in life-threatening cardiac conduction abnormalities.
Hypothesis/Objectives
Compare the effects of IV small-volume hypertonic solutions of NaHCO3, NaCl, and glucose in correcting electrocardiographic abnormalities.
Animals
Twenty-two neonatal diarrheic calves with plasma potassium concentrations (cK) > 5.8 mmol/L.
Methods
Prospective randomized clinical trial. Calves randomly received either 8.4% NaHCO3 (6.4 mL/kg; n = 7), 7.5% NaCl (5 mL/kg; n = 8), or 46.2% glucose (5 mL/kg; n = 7) IV over 5 min and were subsequently allowed to suckle 2 L of an oral electrolyte solution. Lead II ECG variables were determined before the infusion, during infusion, and 7, 15, 30, 60, 90, and 120 min after the start of infusion.
Results
Seven minutes after initiation of infusions, administration of hypertonic sodium solutions but not glucose resulted in a significant (P < .05) increase in heart rate and ST segment duration as well as a decrease in heart rate variability, QRS duration, and T wave amplitude. Generalized linear mixed model analysis identified cK, the interaction between cK and plasma sodium concentrations, or both, as significant predictors of most electrocardiographic variables. Posttreatment increase in cK in 2 calves in group NaCl was associated with the loss of P waves, prolonged QRS duration, and increased T wave amplitude.
Conclusions and clinical importance
Hypertonic sodium solutions allow for a rapid reversal of the cardiotoxic effect of hyperkalemia. Hypertonic NaHCO3 should be preferred over hypertonic NaCl or glucose.