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Evaluation of risk factors, including fluconazole administration, for prolonged anesthetic recovery times in horses undergoing general anesthesia for ocular surgery: 81 cases (2006–2013)

Stephanie R. Krein DVM1, Jane C. Lindsey ScD2, Cheryl A. Blaze BVSc, PhD, MBA3, and Lois A. Wetmore DVM, ScD4
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  • 1 Department of Clinical Sciences, Cummings School of Veterinary Medicine, Tufts University, North Grafton, MA 01536.
  • | 2 Department of Biostatistics, Harvard School of Public Health, Harvard University, Boston, MA 02115.
  • | 3 Department of Clinical Sciences, Cummings School of Veterinary Medicine, Tufts University, North Grafton, MA 01536.
  • | 4 Department of Clinical Sciences, Cummings School of Veterinary Medicine, Tufts University, North Grafton, MA 01536.

Abstract

Objective—To determine risk factors for prolonged anesthetic recovery time in horses that underwent general anesthesia for ocular surgery.

Design—Retrospective cohort study.

Animals—81 horses that underwent general anesthesia for ocular surgery between 2006 and 2013.

Procedures—Descriptive information recorded included the ocular procedure performed, concurrent fluconazole treatments, analgesic and anesthetic agents administered, procedure duration, use of sedation for recovery, and recovery time. Data were analyzed for associations between recovery time and other variables.

Results—81 horses met inclusion criteria. In 72 horses, anesthesia was induced with ketamine and midazolam; 16 horses treated concurrently with fluconazole had significantly longer mean recovery time (109 minutes [95% confidence interval {CI}, 94 to 124 minutes]) than did 56 horses that were not treated with fluconazole (50 minutes [95% CI, 44 to 55 minutes]). In 9 horses anesthetized with a protocol that included ketamine but did not include midazolam, there was no difference between mean recovery time in horses that either received (59 minutes [95% CI, 36 to 81 minutes]; n = 5) or did not receive (42 minutes [95% CI, 16 to 68 minutes]; 4) fluconazole. Other variables identified as risk factors for prolonged recovery included duration of anesthesia and use of acepromazine for premedication.

Conclusions and Clinical Relevance—Fluconazole administration was associated with prolonged anesthetic recovery time in horses when ketamine and midazolam were used to induce anesthesia for ocular surgery. Duration of anesthesia and premedication with acepromazine were also identified as risk factors for prolonged recovery time.

Abstract

Objective—To determine risk factors for prolonged anesthetic recovery time in horses that underwent general anesthesia for ocular surgery.

Design—Retrospective cohort study.

Animals—81 horses that underwent general anesthesia for ocular surgery between 2006 and 2013.

Procedures—Descriptive information recorded included the ocular procedure performed, concurrent fluconazole treatments, analgesic and anesthetic agents administered, procedure duration, use of sedation for recovery, and recovery time. Data were analyzed for associations between recovery time and other variables.

Results—81 horses met inclusion criteria. In 72 horses, anesthesia was induced with ketamine and midazolam; 16 horses treated concurrently with fluconazole had significantly longer mean recovery time (109 minutes [95% confidence interval {CI}, 94 to 124 minutes]) than did 56 horses that were not treated with fluconazole (50 minutes [95% CI, 44 to 55 minutes]). In 9 horses anesthetized with a protocol that included ketamine but did not include midazolam, there was no difference between mean recovery time in horses that either received (59 minutes [95% CI, 36 to 81 minutes]; n = 5) or did not receive (42 minutes [95% CI, 16 to 68 minutes]; 4) fluconazole. Other variables identified as risk factors for prolonged recovery included duration of anesthesia and use of acepromazine for premedication.

Conclusions and Clinical Relevance—Fluconazole administration was associated with prolonged anesthetic recovery time in horses when ketamine and midazolam were used to induce anesthesia for ocular surgery. Duration of anesthesia and premedication with acepromazine were also identified as risk factors for prolonged recovery time.

Contributor Notes

Dr. Krein's present address is Ryan Veterinary Hospital, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104.

Presented in abstract form at the International Veterinary Emergency and Critical Care Symposium, San Antonio, Tex, September 2012.

The authors thank Dr. Nicholas Frank for critical review.

Address correspondence to Dr. Wetmore (Lois.Wetmore@tufts.edu).