Effect of butorphanol administration on cardiovascular parameters in isoflurane-anesthetized horses – a retrospective clinical evaluation.

This research study evaluates the cardiovascular response in horses after the administration of butorphanol during isoflurane-based anesthesia. The findings suggest that butorphanol can be used without adverse effects on heart rate and arterial blood pressure during horse surgeries.

Research Methodology

• The study is based on a retrospective evaluation of anesthetic records of horses undergoing a variety of surgeries.
• The records spanning from January 1999 to December 2003 were scrutinized, focusing on cases where anesthesia was induced with ketamine and a benzodiazepine, maintained with isoflurane, and involved intraoperative administration of butorphanol.
• Horses that had alterations in inotrope infusion rates or end-tidal isoflurane concentration 10 minutes before or after butorphanol administration were not included in the study.
• The horses were categorized into two groups: those in group 1 received butorphanol at intervals as part of a balanced protocol; those in group 2 displayed >=10% increase in heart rate (HR) or blood pressure within 10 minutes prior to butorphanol administration.

Results of the Study

• Overall, 89 butorphanol administration events met the inclusion criteria, with 49 events in group 1 and 40 in group 2.
• In group 1, stakeholders noted no significant changes in systolic arterial pressure (SAP), mean arterial pressure (MAP), diastolic arterial pressure (DAP), heart rate (HR), end-tidal carbon dioxide concentration, or hemoglobin oxygen saturation after administration of butorphanol.
• In contrast, group 2 exhibited significant decreases in SAP, MAP, and DAP following butorphanol administration.

Conclusion

• The research confirms that administering butorphanol to horses under isoflurane anesthesia does not trigger adverse effects on HR and arterial blood pressure.
• The results imply that butorphanol can deepen the plane of anesthesia in horses, also mitigating sympathetic stimulation arising from a surgical procedure.