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Effect of antivenin dose on outcome from crotalid envenomation: 218 dogs (1988–2006)

Authors

  • Jennifer L. McCown DVM, DACVIM,

    1. Department of Small Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, Gainesville, FL 32610,
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  • Kirsten L. Cooke DVM, DACVIM,

    1. Department of Small Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, Gainesville, FL 32610,
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  • Rita M. Hanel DVM, DACVIM, DACVECC,

    1. Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC 27606,
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  • Galin L. Jones BS, MStat, PhD,

    1. School of Statistics, University of Minnesota, Minneapolis, MN 55455.
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  • Richard C. Hill MA, VetMB, PhD, MRCVS, DACVIM, DACVN

    1. Department of Small Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, Gainesville, FL 32610,
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  • Grant support provided by the Florida Veterinary Specialists Charitable Foundation Veterinary Research Fund.

  • Partial results have been presented at IVECCS 2008 in poster format.
    The authors declare no conflicts of interest.

Address correspondence and reprint requests to
Dr. Jennifer McCown, PETS Referral Center, 1048 University Avenue, Berkeley, CA 94710, USA. Email: jlmccown@petsreferralcenter.com

Abstract

Objective – To determine whether the dose of antivenin administered is associated with a difference in survival of crotalid-envenomated dogs. A secondary objective was to determine whether other covariables affect survival.

Design – Retrospective study (1988–2006).

Setting – Private referral center and university small animal teaching hospital.

Animals – Two hundred and eighteen dogs with evidence of crotalid envenomation and treatment with equine-derived antivenin.

Interventions – Administration of antivenin.

Measurements and Main Results – Patient signalment, physical and clinicopathologic data at time of presentation, treatments, complications of antivenin therapy, length and cost of hospitalization, and outcome were recorded. Confidence intervals were determined for the difference in median number of vials administered and for median dosage for patients that lived versus died. Penalized logistic regression was performed to evaluate the effect of other covariables on survival. The median age of affected dogs was 3 years (range 6  w–12  y) with a median weight of 25.7 kg (range 1.95–86.4 kg). The median number of antivenin vials administered was 1.0 (range 1.0–10.0). Acute and chronic reactions were reported in 7% (16/218) and 0.9% (2/218) of dogs, respectively. Nine of 218 dogs (4.1%) died. The median number of vials administered to the nonsurvivors and survivors were 2.0 (range 1–5 vials) and 1.0 (range 1–10 vials), respectively. The median number of vials received was significantly different in dogs that died versus those that lived (P<0.05). Increased heart rate (P=0.02) and petechiation (P=0.04) were associated with decreased likelihood of survival, while diphenhydramine (P=0.02) and fluoroquinolone (P=0.046) administration was associated with increased likelihood of survival. The median duration of hospitalization was 1.0 day (range 2 h–22 d). The median cost of hospitalization was US$1592.00 (range US$267.20–US$6738.00).

Conclusion – The administration of more vials of antivenin is potentially associated with negative outcome; however, a causal relationship has not been established. Controlled, prospective studies are needed to optimize antivenin administration.

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