Antimicrobial regional limb perfusion clinical use in adult horses diagnosed with synovial sepsis or penetrating synovial wounds at a single equine referral hospital in the Mid-Western United States: 163 cases (2010-2020)

Zach Loppnow ¹ Kevin Kersh ² Chong Wang ² Sienna Spaethe ² Jarrod Troy ^2*

• ¹ Steinbeck Peninsula Equine Clinics, Salinas, United States
• ² Iowa State University, Ames, United States

Clinical outcomes in horses diagnosed with established synovial sepsis (SS) or minimally contaminated synovial wounds/non-established sepsis SW following intravenous regional limb perfusion (IVRLP) treatment have not been reported since 2010 and previously were only reported in 2 clinical retrospective reports. [1][2][3] This study's objectives were to provide an update on the short-(hospital discharge) and long-term (> 1-year) survival in adult horses diagnosed with SS or SW treated with IVRLP from 2010-2020 at a single USA institution and determine IVRLP variables associated with survival. The medical records of 163 adult equids diagnosed with SS (group 1) or SW (group 2) from 2010-2020 treated with IVRLP were reviewed. Short-term survival was 88.9% (56/63) for group 1 and 99.0% (99/100) for group 2. Long-term survival was 65.1% (41/63) for group 1 and 83.6% (46/55) for group 2. Gentamicin was the most common IVRLP antimicrobial choice (153/163 cases). Horses in group 1 were less likely to survive to hospital discharge (p=0.01; OR=0.08; 95% CI, [0.01, 0.68]) . The total number of IVRLP performed during hospitalization was significantly associated with non-survival to hospital discharge (p=0.01; OR=0.47; 95% CI, [0.22, 0.87]) with horses less likely to survive as the total number of IVRLP increased. No variables were associated with long-term survival. Overall survival in adult horses diagnosed with SS or SW following treatment is good, and this study provides an updated clinical report of adult equine SS/SW cases that received IVRLP within the USA. This study additionally reports IVRLP variables, including total number of IVRLP & number of consecutive IVRLP, that may be associated with short-term survival.