Faster perfusate instillation time results in more systemic leakage of amikacin sulfate when performing intravenous regional limb perfusion in horses.

This research examined whether the rate at which a drug solution was introduced intravenously to a horse’s leg impacted the concentration of the drug in the joint and its systemic leakage. The results suggest that the rate of introduction did not significantly affect the drug’s concentration in the joint, but faster rates led to more systemic leakage of the drug.

Study Methodology

The study was performed on seven healthy horses in a crossover design, meaning each horse was subject to both treatment procedures with a period in between to allow any effects to wear off. The treatments consisted of:

• Two intravenous regional limb perfusions (IVRLPs), which is a process where a tourniquet is applied to a limb and a drug is introduced into a vein below the tourniquet, in this case, the cephalic vein, to allow it to concentrate in the area before the tourniquet is removed.
• Amikacin, an antibiotic, was the drug used, diluted into a 60mL saline solution.
• The instillation of the drug was introduced either over a 1-minute period (technique 1) or a 5-minute period (technique 5).

Measurement of Concentrations

The concentration of amikacin within the radiocarpal joint (RCJ) and its presence systemically were measured at various times after instillation. These measurements were performed by collecting samples at different time intervals post-instillation and analyzing them using a fluorescence polarization immunoassay (FPIA), a method used to measure the concentration of molecules in a solution by using polarized light.

Results of the Study

The results showed that the maximum concentration of amikacin in the RCJ was not significantly different between the two techniques. However, the systemic blood concentration of amikacin was higher for technique 1 compared to technique 5, suggesting more systemic leakage when the drug was instilled at a faster rate.

Conclusion

Despite the higher systemic leakage with faster rates, the change in instillation rate did not affect the concentration of amikacin within the RCJ, suggesting that the rate of instillation may not need to be strictly controlled to achieve the desired concentration within the joint. However, the researchers noted that the increased systemic leakage observed in the faster instillation process may impact results in a larger sample of horses, suggesting the need for further studies.