• 1. Granholm M, McKusick BC, Westerholm FC, et al. Evaluation of the clinical efficacy and safety of dexmedetomidine or medetomidine in cats and their reversal with atipamezole. Vet Anaesth Analg 2006;33:214223.

    • Search Google Scholar
    • Export Citation
  • 2. McSweeney PM, Martin DD, Ramsey DS, et al. Clinical efficacy and safety of dexmedetomidine used as a preanesthetic prior to general anesthesia in cats. J Am Vet Med Assoc 2012;240:404412.

    • Search Google Scholar
    • Export Citation
  • 3. Escobar A, Pypendop BH, Siao KT, et al. Effect of dexmedetomidine on the minimum alveolar concentration of isoflurane in cats. J Vet Pharmacol Ther 2012;35:163168.

    • Search Google Scholar
    • Export Citation
  • 4. Lamont LA, Bulmer BJ, Grimm KA, et al. Cardiopulmonary evaluation of the use of medetomidine hydrochloride in cats. Am J Vet Res 2001;62:17451749.

    • Search Google Scholar
    • Export Citation
  • 5. Pypendop BH, Barter LS, Stanley SD, et al. Hemodynamic effects of dexmedetomidine in isoflurane-anesthetized cats. Vet Anaesth Analg 2011;38:555567.

    • Search Google Scholar
    • Export Citation
  • 6. Vainio O. Reversal of medetomidine-induced cardiovascular and respiratory changes with atipamezole in dogs. Vet Rec 1990;127:447450.

    • Search Google Scholar
    • Export Citation
  • 7. Martin-Flores M, Sakai DM, Honkavaara J, et al. Hemodynamic effects of low-dose atipamezole in isoflurane-anesthetized cats receiving an infusion of dexmedetomidine. J Feline Med Surg 2018;20:571577.

    • Search Google Scholar
    • Export Citation
  • 8. Sellgren J, Biber B, Henriksson BA, et al. The effects of propofol, methohexitone and isoflurane on the baroreceptor reflex in the cat. Acta Anaesthesiol Scand 1992;36:784790.

    • Search Google Scholar
    • Export Citation
  • 9. Krivitski NM, Kislukhin VV, Thuramalla NV. Theory and in vitro validation of a new extracorporeal arteriovenous loop approach for hemodynamic assessment in pediatric and neonatal intensive care unit patients. Pediatr Crit Care Med 2008;9:423428.

    • Search Google Scholar
    • Export Citation
  • 10. Dunkle N, Moise NS, Scarlett-Kranz J, et al. Cardiac performance in cats after administration of xylazine or xylazine and glycopyrrolate: echocardiographic evaluations. Am J Vet Res 1986;47:22122216.

    • Search Google Scholar
    • Export Citation
  • 11. Sinclair MD, O'Grady MR, Kerr CL, et al. The echocardiographic effects of romifidine in dogs with and without prior or concurrent administration of glycopyrrolate. Vet Anaesth Analg 2003;30:211219.

    • Search Google Scholar
    • Export Citation
  • 12. Ko JC, Fox SM, Mandsager RE. Effects of preemptive atropine administration on incidence of medetomidine-induced bradycardia in dogs. J Am Vet Med Assoc 2001;218:5258.

    • Search Google Scholar
    • Export Citation
  • 13. Boehne M, Baustert M, Paetzel V, et al. Determination of cardiac output by ultrasound dilution technique in infants and children: a validation study against direct Fick principle. Br J Anaesth 2014;112:469476.

    • Search Google Scholar
    • Export Citation
  • 14. Veal N, Moal F, Wang J, et al. New method of cardiac output measurement using ultrasound velocity dilution in rats. J Appl Physiol 2001;91:12741282.

    • Search Google Scholar
    • Export Citation
  • 15. Darling E, Thuramalla N, Searles B. Validation of cardiac output measurement by ultrasound dilution technique with pulmonary artery thermodilution in a pediatric animal model. Pediatr Cardiol 2011;32:585589.

    • Search Google Scholar
    • Export Citation
  • 16. Shih A, Giguere S, Vigani A, et al. Determination of cardiac output by ultrasound velocity dilution in normovolemia and hypovolemia in dogs. Vet Anaesth Analg 2011;38:279285.

    • Search Google Scholar
    • Export Citation

Advertisement

Evaluation of atipamezole as a treatment for dexmedetomidine-induced cardiovascular depression in anesthetized cats

View More View Less
  • 1 1Department of Clinical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853
  • | 2 2Cornell University Statistical Consulting Unit, College of Human Ecology, Cornell University, Ithaca, NY 14853

Abstract

OBJECTIVE

To evaluate the cardiovascular effects of atipamezole administered at half the volume or the same volume as dexmedetomidine to isoflurane-anesthetized cats.

ANIMALS

6 adult (1 to 2 years old) domestic shorthair cats (body weight, 3 to 6 kg).

PROCEDURES

Each cat was anesthetized with isoflurane and rocuronium 3 times; there was a 1-week washout period between successive anesthetic procedures. For each anesthetic procedure, dexmedetomidine (5 μg/kg) was administered IV. Five minutes after dexmedetomidine was administered, atipamezole (25 or 50 μg/kg) or saline (0.9% NaCl) solution was administered IM. Pulse rate, mean arterial blood pressure (MAP), cardiac output (CO), and systemic vascular resistance (SVR) were measured during anesthesia before dexmedetomidine administration (baseline), after dexmedetomidine administration, and 15, 30, 60, and 120 minutes after administration of atipamezole or saline solution. Pulse rate and MAP were also recorded when MAP was at its lowest value. Hemodynamic variables were compared among treatments at baseline, after dexmedetomidine administration, and after administration of atipamezole or saline solution. Effects of treatment and time on all variables were assessed with mixed-effects models.

RESULTS

Both doses of atipamezole resulted in a significantly lower MAP than did saline solution. Pulse rate, CO, and SVR were not significantly different among treatments after atipamezole or saline solution were administered.

CONCLUSIONS AND CLINICAL RELEVANCE

Atipamezole administered IM at half the volume or the same volume as dexmedetomidine was ineffective at increasing pulse rate or CO in anesthetized cats that received dexmedetomidine. However, atipamezole caused short-lasting but severe arterial hypotension.

Abstract

OBJECTIVE

To evaluate the cardiovascular effects of atipamezole administered at half the volume or the same volume as dexmedetomidine to isoflurane-anesthetized cats.

ANIMALS

6 adult (1 to 2 years old) domestic shorthair cats (body weight, 3 to 6 kg).

PROCEDURES

Each cat was anesthetized with isoflurane and rocuronium 3 times; there was a 1-week washout period between successive anesthetic procedures. For each anesthetic procedure, dexmedetomidine (5 μg/kg) was administered IV. Five minutes after dexmedetomidine was administered, atipamezole (25 or 50 μg/kg) or saline (0.9% NaCl) solution was administered IM. Pulse rate, mean arterial blood pressure (MAP), cardiac output (CO), and systemic vascular resistance (SVR) were measured during anesthesia before dexmedetomidine administration (baseline), after dexmedetomidine administration, and 15, 30, 60, and 120 minutes after administration of atipamezole or saline solution. Pulse rate and MAP were also recorded when MAP was at its lowest value. Hemodynamic variables were compared among treatments at baseline, after dexmedetomidine administration, and after administration of atipamezole or saline solution. Effects of treatment and time on all variables were assessed with mixed-effects models.

RESULTS

Both doses of atipamezole resulted in a significantly lower MAP than did saline solution. Pulse rate, CO, and SVR were not significantly different among treatments after atipamezole or saline solution were administered.

CONCLUSIONS AND CLINICAL RELEVANCE

Atipamezole administered IM at half the volume or the same volume as dexmedetomidine was ineffective at increasing pulse rate or CO in anesthetized cats that received dexmedetomidine. However, atipamezole caused short-lasting but severe arterial hypotension.

Contributor Notes

Dr. Sakai's present address is Department of Small Animal Medicine and Surgery, College of Veterinary Medicine, University of Georgia, Athens, GA 30602.

Address correspondence to Dr. Martin-Flores (martinflores@cornell.edu).