Pharmacokinetics of procaine injected into the hock joint of the horse.

This research studied the distribution and effects of anaesthetic, specifically procaine, when injected into the hock joint of a horse. Findings included the effective volumes of anaesthetic to be used and how it was distributed across the joint over a certain time period.

Introduction

• The paper investigates the use of procaine, an anaesthetic, in treating joint pain in horses.
• Considerations for its use include the volume necessary to effectively manage pain without causing too much of the solution to escape and lose its effectiveness.
• Research is being built upon others’ work suggesting different volumes of anaesthetic — the paper specifically notes recommendations from a collection of researchers including Berge and Westhues, Tufvesson, Hall, and Soma.

Methodology

• This study involved thoroughbred horses, halfbreds, and ponies, with weights ranging from 250kg to 680kg.
• 17 horses were administered the anaesthetic under general anaesthesia, and a cannula was left in the joint to allow for withdrawal of samples without repeated puncturing of the joint.
• Four horses were injected in both hocks without the use of general anaesthesia.
• Procaine hydrochloride in varying concentrations was used, with volumes ranging from 2ml to 30ml. Volumes above 5ml were less commonly used, exclusively in 6 joints.

Results Gathering

• Synovial samples were drawn at intervals within a 75-120 minute period following injection.
• These samples were then refrigerated until further analysis could be performed.
• The concentration of procaine in the synovial fluid was determined using Soehring and Pape’s method (1949).
• Afterwards, concentrations were plotted over time to find out the half-life of procaine in the horse joint.

Objectives and Implications for Future

• This research was designed to provide a reliable measure regarding the precise volume and concentration of procaine to maximise its effectiveness when injected in the hock joint of horses.
• The findings can potentially contribute to better anesthesia practices in veterinary medicine particularly for the management of joint pain in equine species.