Buffering mepivacaine with sodium bicarbonate speeds and potentiates analgesia of median and ulnar nerve blocks performed on horses.

This research investigates the impact of buffering mepivacaine with sodium bicarbonate on the time it takes for pain relief to begin when applying nerve blocks on horses. The study discovered that the combination of the two substances hastened the onset and amplified the strength of pain relief in horses suffering natural lameness.

Research Methodology

• The study involved nerve block applications on the naturally lame limbs of nine horses across two distinct study periods, ensuring a minimum of three days ‘washout period’ between the study periods. The ‘washout period’ means the period when no drugs are given to ensure the previously administered drugs are out of the animal’s system. This was done to ensure the absence of any lingering effects from the first period that could potentially affect the results of the second period.
• The nerve blocks were administered either by using mepivacaine HCL (mepHCl) alone or by using mepHCl mixed with Sodium bicarbonate (NaHCO) in a specific ratio (nine parts 2 per cent mepHCl to one part 8.4 per cent NaHCO).
• The degree of the horses’ lameness was assessed using a wireless, sensor-based, motion analysis system (Lameness Locator). This was done prior to applying the high regional nerve block and then every five minutes post application for a span of 75 minutes.

Key Findings

• The results demonstrated a faster onset of analgesia when mixing mepHCl with NaHCO as compared to using mepHCl alone. Analgesia refers to the absence of pain in response to stimulation which would normally cause pain.
• The strength of pain relief was also found to be more potent when the two substances were used together, implying greater effectiveness in treating lameness.
• The study validates that preparing a mixture of mepHCl with NaHCO for median and ulnar nerve blocks could provide a more rapid and robust analgesic effect for horses that are naturally lame.

Implications of the Study

• The research findings could be of significant potential benefit to veterinary practices, especially those working with horses. It can lead to better procedures for handling lameness in horses, providing quicker and more potent pain relief.
• This could make treatment more effective and also improve the welfare of the animals, reducing their suffering when they are in pain.
• The mixing of mepHCl with NaHCO could be a valuable technique in the field of veterinary medicine for faster and more effective handling of pain.