Furosemide and sodium bicarbonate-induced alkalosis in the horse and response to oral KCl or NaCl therapy.

The study investigated the effects of treating horses with furosemide and sodium bicarbonate, and whether orally-administered potassium or sodium chloride could correct induced metabolic alkalosis. Notably, the alkalosis lasted for 24 hours and was linked with a considerable decrease in chloride and potassium levels.

Research Design and Methods

• In the experiment, the researchers triggered metabolic alkalosis in ten healthy horses by administering furosemide followed 4.5 hours later by sodium bicarbonate via a nasogastric tube. This process caused a mean weight loss of 21.1 kg in the horses.
• The experiment found significant increases in venous blood pH, bicarbonate, and plasma protein concentrations, while observed a decrease in plasma potassium, chloride, and calcium concentrations.
• Notably, the oral introduction of the hypertonic sodium bicarbonate solution led to clinical symptoms of hypovolemia, which was linked to a marked uptick in plasma protein concentration.

Observations and Findings

• Following the administration of the hypertonic sodium bicarbonate solution, seven out of the ten horses showed signs of neuromuscular excitability, including muscle fasciculations. Half of the horses also developed a diaphragmatic flutter.
• The experiment induced transient hypernatremia, but this condition resolved as the horses were granted access to water.
• Importantly, the alkalosis induced by the administration of furosemide and sodium bicarbonate was profound, persisted for a full day, and was associated with marked decreases in chloride and potassium levels.

Results of Replacement Therapy

• In an attempt to replace the electrolyte deficits and correct the alkalosis, the researchers administered 1,000 mEq of either sodium or potassium chloride to the horses via a nasogastric tube (in an isotonic solution).
• The horses that received the potassium chloride treatment displayed a significant decrease in venous blood pH and bicarbonate concentration. This response was accompanied by significant increase in plasma potassium concentration, indicating the treatment’s effectiveness.