Antinociceptive Effect of Intravenous Regional Analgesia in Horses Underwent Selected Short-Time Distal Limb Surgeries.

The research primarily focuses on determining the appropriate doses of lidocaine hydrochloride (Hcl) and mepivacaine for intravenous regional analgesia (IVRA) in horses and to assess their effectiveness in reducing pain during and after surgeries of the distal limb.

Research Design and Methodology

• The study included 55 draft horses, out of which six clinically healthy ones were randomly selected to establish the dosage for lidocaine Hcl and mepivacaine in IVRA treatment for horse limbs.
• After determining the dosages, 32 horses suffering from various distal limb surgical conditions were split into three groups: the thiopental group (n=6), IVRA-LID group (n=12), and IVRA-MEP group (n=14).
• The thiopental group was operated under general anesthesia using thiopental sodium, the IVRA-LID group was operated under both general anesthesia and IVRA using lidocaine Hcl, and the IVRA-MEP group was operated under both general anesthesia and IVRA using mepivacaine.
• The pain experienced by the horses post-surgery was measured using the Horse Grimace Pain Scale and a multifactorial numerical rating composite pain scale.

Key Findings

• Results of the study found that using IVRA paired with thiopental general anesthesia using either lidocaine or mepivacaine substantially reduced the total required doses of thiopental sodium during the operations.
• The combination also significantly increased the duration of postoperative analgesia up to 60 minutes when using lidocaine and up to 150 minutes when using mepivacaine.
• These findings suggest that the use of IVRA before distal limb surgery can improve the depth of general anesthesia and reduce postoperative pain in horses, providing a better alternative to the use of thiopental anesthesia alone.
• Mepivacaine proved superior to lidocaine in IVRA as it provided a longer-lasting pain relief.

Conclusion

• The study successfully determined the appropriate doses of lidocaine hydrochloride (Hcl) and mepivacaine for intravenous regional analgesia (IVRA) in horses for distal limb surgeries.
• It was concluded that combining IVRA with general anesthesia can enhance the procedure and provide more effective and longer-lasting pain relief post-surgery.
• The results point to a positive future direction in equine medicine, particularly for performing distal limb surgeries on horses.