Comparison of the cardiopulmonary effects of anesthesia maintained by continuous infusion of romifidine, guaifenesin, and ketamine with anesthesia maintained by inhalation of halothane in horses.

This research study investigates the cardiopulmonary effects during anesthesia on horses comparing the usage of halothane with a total intravenous anesthetic (TIVA) regimen. The findings reveal that the TIVA regimen, using a mixture of romifidine, guaifenesin, and ketamine, stabilized higher arterial blood pressures than halothane, and can possibly result in better left ventricular function.

Research Methods

• Seven healthy adult horses were used for the study, and each horse was anesthetized twice.
• Romifidine was introduced into the system intravenously (IV), after which anesthesia was activated using ketamine also administered intravenously.
• The anesthesia was sustained for a duration of 75 minutes either through the utilization of halothane (HA) or by an IV infusion of the TIVA mixture of romifidine, guaifenesin, and ketamine.
• The order in which HA or TIVA was used was randomized across the subjects to avoid the impact of order effects.
• Various cardiopulmonary variables such as systolic, diastolic, and mean carotid arterial pressures, and others were measured at three distinct points—40, 60, and 75 minutes into the administration of either HA or TIVA.

Research Findings

• Results illustrated that several measured variables, including the systolic, diastolic, and mean carotid arterial pressures, among others, were more significant during the use of TIVA than HA.
• Conversely, systolic, diastolic, and mean pulmonary arterial pressure were lower during TIVA administration.
• Furthermore, heart rate was found to be higher during halothane administration at the 60-minute mark.
• In terms of respiratory factors, TIVA showed higher minute and alveolar ventilation and a more extended inspiratory time than HA at 75 minutes.
• The level of Carbon Dioxide (PaCO2) in arterial blood was higher at 60 and 75 minutes for HA than TIVA.
• These results suggest that the constant-rate infusion of TIVA maintained higher arterial blood pressures in horses compared to HA use.

Conclusion

• While there is a suggestion from the study that left ventricular function might be better during the TIVA regimen, certain factors such as preload and afterload, which were not taken into account in this study, could influence the results.