Influence of digoxin followed by dopamine on the cardiovascular depression during a standard halothane anaesthesia in dorsally recumbent, ventilated ponies.

The research conducted in this study investigates the impact of digoxin and dopamine on cardiovascular depression that occurs during standard halothane anesthesia in ponies. The results suggest that the combination of these two medications might be beneficial in addressing cardiovascular depression during clinical anesthesia in horses.

Research Procedure

• The researchers administered digoxin (0.01 mg/kg) as an initial intravenous bolus, followed by dopamine at varying infusion rates (1.25, 2.5, and 5.0 micrograms/kg/min).
• The experiment was carried out on ponies in a dorsally recumbent position under ventilated conditions.
• The effects of the medications on the cardiovascular symptoms of the ponies during standard halothane anesthesia were then monitored and recorded.

Results of the Study

• The preanaesthetic digitalization with digoxin showed no obvious positive cardiovascular effects over 30 minutes, apart from non-significant increases in mean pulmonary artery pressure and total pulmonary resistance. According to the researchers, these changes seemed to relate to time rather than the medication.
• The team observed no specific side effects related to the fast intravenous digitalization process.
• After this, lower doses of dopamine (1.25 and 2.5 micrograms/kg/min) administered at least 30 minutes post the digitalization did not induce additional changes. The exceptions were minor, non-significant increases in cardiac output and systemic blood pressure.
• Higher doses of dopamine infusion (5.0 micrograms/kg/min) positively impacted the cardiovascular depression. The researchers noted significant increases in cardiac output and systemic blood pressure, while total peripheral resistance seemed to decrease.
• The ponies’ heart rate, blood gases, and total pulmonary resistance remained steady throughout.

Conclusion of the Study

• The findings from this research indicate that the combination of digoxin, a slow acting inotropic drug, and dopamine, a fast acting inotropic agent, can have positive effects in reversing cardiovascular depression.
• As a result, this combination could have potential uses during clinical anesthesia in horses.