Retrospective study of perioperative antimicrobial use practices in horses undergoing elective arthroscopic surgery at a veterinary teaching hospital.

Perioperative antimicrobial administration practices were evaluated retrospectively in 97 horses undergoing elective arthroscopy, and antimicrobial use was compared with standard recommendations for perioperative prophylaxis. Parenteral antimicrobials were administered perioperatively to 95/97 (98%) horses, 88 of which received intravenous sodium penicillin. Time from 1st dose until 1st incision ranged from 30 to 390 min [142 +/- 55.6 min, mean +/- standard deviation (s), median 135 min], and the first incision was performed greater than 2 half-lives after administration of sodium penicillin in 86/95 (91%) cases. Overall duration of therapy was 30.8 +/- 24.2 h (mean +/- s). Six (6.3%) horses received only a single preoperative dose, while 63 (66%) horses were treated for 24 h or less. While objective data regarding optimal perioperative antimicrobial prophylaxis are limited, the antimicrobial use practices observed here commonly deviated from standard recommendations for perioperative prophylaxis.