Different methods of perfusate administration do not have an effect on synovial concentrations of amikacin following intravenous regional limb perfusion.

Objective: To determine if different methods of perfusate instillation influence synovial amikacin concentrations in the radiocarpal joint (RCJ) after IV regional limb perfusion (IVRLP).

Methods: 6 healthy horses received an IVRLP using 2 different methods: (1) 2 g amikacin followed by 52 mL 0.9% NaCl (60 mL total; perfusate-A) and (2) 2 g amikacin diluted to 60 mL with 0.9% NaCl (perfusate-D). For both methods, the perfusion was administered over 5 minutes. Joint fluid from the RCJ was sampled at 10, 15, 20, 25, and 30 minutes after instillation of the perfusate. Systemic concentrations of amikacin were measured prior to IVRLP; at 5, 10, 15, 20, 25, and 29 minutes; and 1 minute after tourniquet removal. Amikacin concentrations were determined by fluorescence polarization immunoassay.

Results: Mean ± SD peak synovial concentration in the RCJ was 1,447 ± 1,134 μg/mL with perfusate-D and 1,170 ± 977 μg/mL with perfusate-A. Mean ± SD time to peak concentration was 18 ± 7 minutes with perfusate-D and 20 ± 5 minutes with perfusate-A. There was no difference in peak synovial concentration (P = .684) and time to peak concentration (P = .732) between groups. There was no difference in systemic amikacin concentrations over time between groups (P = .196). All horses included reached the target synovial amikacin concentration of > 160 μg/mL.

Conclusions: There was no difference in the systemic or the synovial concentrations of amikacin using different methods of perfusate administration.

Clinical Relevance: Different methods of perfusate administration did not affect synovial concentrations of amikacin achieved when performing IVRLP. There is no advantage to administering amikacin first.