Sevoflurane and oxygen anaesthesia following administration of atropine-xylazine-guaifenesin-thiopental in spontaneously breathing horses.

The research presents the effects of sevoflurane-oxygen anesthesia in spontaneously breathing horses pre-administered with atropine, xylazine, and guaifenesin-thiopental. The outcomes highlight a rapid and smooth recovery, stable heart rates and no significant alteration in various blood parameters except mild respiratory acidosis and haemodilution during anesthesia.

Study objective and methodology

• The study aims to evaluate the impact of sevoflurane-oxygen anesthesia at a light-surgical depth on key clinical characteristics in horses that were pre-administered with atropine, xylazine, guaifenesin-thiopental. This goal was to observe and measure these effects during and after anesthesia.
• Throughout a 90-minute maintenance period, the average end-tidal concentrations of sevoflurane varied from 1.6 to 2.3%. The parameters evaluated during this period included the heart rate, arterial pressure, minute ventilation, arterial blood gases, and pH.

Findings

• The horses exhibited a swift and smooth recovery from anesthesia, exhibiting the effectiveness of sevoflurane as an inhalant anesthetic.
• No significant changes were observed in the heart rates after anesthesia, demonstrating the safety of the selected anesthetic protocol. Importantly, no arrhythmia was noted post anesthetic administration.
• Observations showed stable arterial pressure ranging from 86 +/- 17 to 98 +/- 5 mmHg during anesthesia, which indicates that circulatory stability was maintained throughout the anesthesia period.
• Respiratory rates dipped during anesthesia, resulting in decreased minute ventilation. This change led to respiratory acidosis, as evident from changes in arterial blood gases and pH levels.
• Haemodilution was observed during anesthesia, based on the hematological findings. This could potentially be a consequence of fluid therapy during anesthesia.
• There was a minor decrease in serum potassium during anesthesia, but no other noteworthy variations were seen in serum biochemical values.

Implications and conclusion

• The results suggest that sevoflurane might be an effective inhalant anesthetic because it allows a rapid recovery from anesthesia in horses and manages to maintain heart rates and serum biochemical values.
• The study opens up a discussion on sevoflurane anesthesia as a preferable method due to its positive outcomes, minimal physiological disruption, and rapid recovery time.