• 1. Steagall PV, Teixeira-Neto FJ, Minto BW, et al. Evaluation of isoflurane-sparing effects of lidocaine and fentanyl during surgery in dogs. J Am Vet Med Assoc 2006; 229: 522527.

    • Search Google Scholar
    • Export Citation
  • 2. Pascoe PJ, Ilkiw JE, Fisher LD. Cardiovascular effects of equipotent isoflurane and alfentanil/isoflurane minimum alveolar concentration multiple in cats. Am J Vet Res 1997; 58: 12671273.

    • Search Google Scholar
    • Export Citation
  • 3. Pypendop BH, Brosnan RJ, Siao KT, et al. Pharmacokinetics of remifentanil in conscious cats and cats anesthetized with isoflurane. Am J Vet Res 2008; 69: 531536.

    • Search Google Scholar
    • Export Citation
  • 4. Ferreira TH, Agular AJ, Valverde A, et al. Effect of remifentanil hydrochloride administered via constant rate infusion on the minimum alveolar concentration of isoflurane in cats. Am J Vet Res 2009; 70: 581588.

    • Search Google Scholar
    • Export Citation
  • 5. Brosnan RJ, Pypendop BH, Siao KT, et al. Effects of remifentanil on measures of anesthetic immobility and analgesia in cats. Am J Vet Res 2009; 70: 10651071.

    • Search Google Scholar
    • Export Citation
  • 6. Monteiro ER, Teixeira-Neto FJ, Campagnol D, et al. Effects of remifentanil on minimum alveolar concentration of isoflurane in dogs. Am J Vet Res 2010; 71: 150156.

    • Search Google Scholar
    • Export Citation
  • 7. Steagall PV, Monteiro-Steagall BP. Multimodal analgesia for perioperative pain in three cats. J Feline Med Surg 2013; 15: 737743.

  • 8. Pascoe PJ, Ilkiw JE, Craig C, et al. The effects of ketamine on the minimum alveolar concentration of isoflurane in cats. Vet Anaesth Analg 2007; 34: 3139.

    • Search Google Scholar
    • Export Citation
  • 9. Hodgson DS, Dunlop CI, Chapman PL, et al. Cardiopulmonary effects of anesthesia induced and maintained with isoflurane in cats. Am J Vet Res 1998; 59: 182185.

    • Search Google Scholar
    • Export Citation
  • 10. Mathews K, Kronen PW, Lascelles D, et al. Guidelines for recognition, assessment and treatment of pain: WSAVA Global Pain Council members and co-authors of this document. J Small Anim Pract 2014; 55: E10E68.

    • Search Google Scholar
    • Export Citation
  • 11. Slingsby LS, Waterman-Pearson AE. The post-operative analgesic effects of ketamine after canine ovariohysterectomy—a comparison between pre- or post-operative administration. Res Vet Sci 2000; 69: 147152.

    • Search Google Scholar
    • Export Citation
  • 12. Wagner AE, Walton JA, Hellyer PW, et al. Use of low doses of ketamine administered by constant rate infusion as an adjunct for postoperative analgesia in dogs. J Am Vet Med Assoc 2002; 221: 7275.

    • Search Google Scholar
    • Export Citation
  • 13. Kehlet H, Dahl JB. The value of “multimodal” or “balanced analgesia” in postoperative pain treatment. Anesth Analg 1993; 77: 10481056.

    • Search Google Scholar
    • Export Citation
  • 14. Correa Mdo A, Aguiar AJ, Neto FJ, et al. Effects of remifentanil infusion regimens on cardiovascular function and responses to noxious stimulation in propofol-anesthetized cats. Am J Vet Res 2007; 68: 932940.

    • Search Google Scholar
    • Export Citation
  • 15. Padilha ST, Steagall PV, Monteiro BP, et al. A clinical comparison of remifentanil or alfentanil in propofol-anesthetized cats undergoing ovariohysterectomy. J Feline Med Surg 2011; 13: 738743.

    • Search Google Scholar
    • Export Citation

Advertisement

Clinical effects of a constant rate infusion of remifentanil, alone or in combination with ketamine, in cats anesthetized with isoflurane

View More View Less
  • 1 Department of Clinical Sciences, Faculty of Veterinary Medicine, University of Montreal, Saint-Hyacinthe, QC J2S 2M2, Canada.
  • | 2 Department of Clinical Sciences, Faculty of Veterinary Medicine, University of Montreal, Saint-Hyacinthe, QC J2S 2M2, Canada.
  • | 3 Department of Biomedical Sciences, Faculty of Veterinary Medicine, University of Montreal, Saint-Hyacinthe, QC J2S 2M2, Canada.
  • | 4 Department of Biomedical Sciences, Faculty of Veterinary Medicine, University of Montreal, Saint-Hyacinthe, QC J2S 2M2, Canada.
  • | 5 Department of Clinical Sciences, School of Veterinary Medicine, Ross University, St Kitts, West Indies.
  • | 6 Department of Clinical Sciences, Faculty of Veterinary Medicine, University of Montreal, Saint-Hyacinthe, QC J2S 2M2, Canada.

Abstract

Objective—To evaluate the effects of a constant rate infusion of remifentanil, alone or in combination with ketamine, in healthy cats anesthetized with isoflurane.

Design—Randomized, controlled, clinical trial.

Animals—23 cats undergoing elective ovariohysterectomy.

Procedures—Cats were premedicated with acepromazine and morphine; anesthesia was induced with propofol and maintained with isoflurane. Cats were given constant rate infusions of remifentanil (20 μg/kg/h [9 μg/lb/h], IV; n = 8), remifentanil and ketamine (0.5 mg/kg [0.23 mg/lb], then 1.8 mg/kg/h [0.82 mg/lb/h], IV; 7), or crystalloid fluids (8). The anesthesiologist was blinded to treatment group, end-tidal isoflurane concentration, and vaporizer setting. Heart rate, systolic arterial blood pressure, respiratory rate, end-tidal partial pressure of CO2, temperature, and end-tidal isoflurane concentration were monitored; recovery scores were assigned.

Results—There were no significant differences among treatment groups with respect to age, body weight, surgery time, anesthesia time, time to extubation, recovery score, or cardiorespiratory variables. End-tidal isoflurane concentration was significantly reduced in cats given remifentanil and ketamine (mean ± SD, 0.63 ± 0.4%), compared with concentration in cats given crystalloid fluids (1.22 ± 0.5%) but not compared with concentration in cats given remifentanil alone (1.03 ± 0.4%). Compared with cats given crystalloid fluids, mean isoflurane requirement was reduced by 48.3% in cats given remifentanil-ketamine and 15.6% in cats given remifentanil alone.

Conclusions and Clinical Relevance—At the dosages administered, a constant rate infusion of remifentanil-ketamine resulted in a significant decrease in the isoflurane requirement in healthy cats undergoing ovariohysterectomy. However, significant differences in cardiovascular variables were not observed among treatment groups.

Abstract

Objective—To evaluate the effects of a constant rate infusion of remifentanil, alone or in combination with ketamine, in healthy cats anesthetized with isoflurane.

Design—Randomized, controlled, clinical trial.

Animals—23 cats undergoing elective ovariohysterectomy.

Procedures—Cats were premedicated with acepromazine and morphine; anesthesia was induced with propofol and maintained with isoflurane. Cats were given constant rate infusions of remifentanil (20 μg/kg/h [9 μg/lb/h], IV; n = 8), remifentanil and ketamine (0.5 mg/kg [0.23 mg/lb], then 1.8 mg/kg/h [0.82 mg/lb/h], IV; 7), or crystalloid fluids (8). The anesthesiologist was blinded to treatment group, end-tidal isoflurane concentration, and vaporizer setting. Heart rate, systolic arterial blood pressure, respiratory rate, end-tidal partial pressure of CO2, temperature, and end-tidal isoflurane concentration were monitored; recovery scores were assigned.

Results—There were no significant differences among treatment groups with respect to age, body weight, surgery time, anesthesia time, time to extubation, recovery score, or cardiorespiratory variables. End-tidal isoflurane concentration was significantly reduced in cats given remifentanil and ketamine (mean ± SD, 0.63 ± 0.4%), compared with concentration in cats given crystalloid fluids (1.22 ± 0.5%) but not compared with concentration in cats given remifentanil alone (1.03 ± 0.4%). Compared with cats given crystalloid fluids, mean isoflurane requirement was reduced by 48.3% in cats given remifentanil-ketamine and 15.6% in cats given remifentanil alone.

Conclusions and Clinical Relevance—At the dosages administered, a constant rate infusion of remifentanil-ketamine resulted in a significant decrease in the isoflurane requirement in healthy cats undergoing ovariohysterectomy. However, significant differences in cardiovascular variables were not observed among treatment groups.

Contributor Notes

Supported by the Association des médecins vétérinaires praticiens du Québec.

The authors thank Robert Cook, Genevieve Dery, Dr. Raphael Vezina, and Dr. Javier Benito for technical assistance.

Address correspondence to Dr. Steagall (psteagall@gmail.com).