• Rocio Navarrete, Setefilla Quirós-Carmona, María Del M Granados, Rafael J Gómez-Villamandos, Juan M Domínguez, José A Férnandez-Sarmiento, Pilar Muñoz-Rascón, Francisco J Funes, and Juan Morgaz.
• Department of Animal Medicine and Surgery, Anaesthesia Unit, Veterinary Faculty, University of Córdoba, Córdoba, Spain.
• Vet Anaesth Analg. 2016 Jul 1; 43 (4): 397-404.

ObjectiveTo assess the effect of two rates of infusion of dexmedetomidine on the bispectral index (BIS) in dogs anaesthetized with alfaxalone constant rate infusion (CRI).Study DesignProspective, randomized, 'blinded' experimental study.AnimalsSix healthy Beagles (three females and three males).MethodsDogs received as premedication saline (group D0), 1 μg kg(-1) (group D1) or 2 μg kg(-1) (group D2) dexmedetomidine, intravenously (IV). Anaesthesia was induced with alfaxalone (6 mg kg(-1) to effect IV) and maintained with alfaxalone at 0.07 mg kg(-1)  minute(-1) and a CRI of saline (D0) or dexmedetomidine 0.5 μg kg(-1)  hour(-1) (D1) or 1 μg kg(-1)  hour(-1) (D2) for 90 minutes. BIS, electromyography (EMG), signal quality index (SQI) and suppression ratio (SR) were measured at 10 minute intervals and the median values were calculated. Nociceptive stimuli were applied every 30 minutes and BIS and cardiorespiratory values were compared before and after stimuli. Cardiorespiratory parameters were recorded throughout the study.ResultsBIS and EMG values differed significantly among groups, being lower in D2 (71 ± 8) than in D0 (85 ± 10) and D1 (84 ± 9). SQI was always over 90% and SR was zero throughout all the treatments. There were no significant differences between pre- and post-stimulus values of BIS, EMG and SQI for any treatment, although in D0 and D1, heart rate, respiratory rate and arterial pressures increased significantly after the nociceptive stimulus.Conclusions And Clinical RelevanceAdministration of dexmedetomidine (2 μg kg(-1)  + CRI 1 μg kg(-1)  hour(-1) ) decreases the BIS values and avoids the autonomic responses of a nociceptive stimulus during alfaxalone anaesthesia at 0.07 mg kg(-1)  minute(-1) in dogs. However, further studies are needed to verify whether this combination produces an adequate degree of hypnosis under surgical situations.© 2015 Association of Veterinary Anaesthetists and the American College of Veterinary Anesthesia and Analgesia.

29 keywords...

hide…