title: Sedative and echocardiographic effects of dexmedetomidine combined with butorphanol in healthy dogs.
abstract: OBJECTIVE
  To evaluate the echocardiographic variables and sedation after two dosages of dexmedetomidine combined with butorphanol in healthy dogs.
  
  
  METHODS
  Fourteen healthy dogs.
  
  
  METHODS
  The dogs received dexmedetomidine 5 mcg/kg IM and butorphanol 0.4 mg/kg (low dose (LD), n = 6) or dexmedetomidine 10 mcg/kg IM and butorphanol 0.4 mg/kg (recommended dose (RD), n = 8). Sedation scoring, noninvasive blood pressure measurement, and echocardiography were performed before sedation at baseline, at 20 minutes (T20), and 60 minutes (T60) after drug administration.
  
  
  RESULTS
  The median sedation scores were increased at both T20 and T60 in the RD group, and at T60 in the LD group, compared with baseline (p < 0.0001, p = 0.012). At T60, the RD dogs were more sedated than the LD dogs (p = 0.0093). The median cardiac output (CO) decreased at both T20 (63%) and T60 (65%) in the RD group and at T60 (42%) in the LD group, compared with baseline (p = 0.0011, p = 0.0055). The median heart rate (HR) was decreased at both T20 and T60 in the RD group and at T60 in the LD group, compared with baseline (p = 0.0009, p = 0.0001). In both RD and LD dogs, valvular regurgitation developed and was identified by color Doppler imaging.
  
  
  CONCLUSIONS
  There were significant hemodynamic changes, mainly related to HR and indices of systolic function, following administration of dexmedetomidine in these healthy dogs. The changes also included decreases in systolic function and CO, as well as appearance of 'new' valvular regurgitation. Caution should be used when considering dexmedetomidine for sedation in dogs with, or being screened for, cardiovascular disease.
authors.affiliation: Department of Medical Sciences, School of Veterinary Medicine, University of Wisconsin, 2015 Linden Dr., Madison, WI 53706, USA. Electronic address: kellihanh@vetmed.wisc.edu.
authors.forename: H B
authors.initials: HB
authors.lastname: Kellihan
authors.affiliation: Department of Medical Sciences, School of Veterinary Medicine, University of Wisconsin, 2015 Linden Dr., Madison, WI 53706, USA.
authors.forename: R L
authors.initials: RL
authors.lastname: Stepien
authors.affiliation: Department of Medical Sciences, School of Veterinary Medicine, University of Wisconsin, 2015 Linden Dr., Madison, WI 53706, USA.
authors.forename: K M
authors.initials: KM
authors.lastname: Hassen
authors.affiliation: Department of Surgical Sciences, School of Veterinary Medicine, University of Wisconsin, 2015 Linden Dr., Madison, WI 53706, USA.
authors.forename: L J
authors.initials: LJ
authors.lastname: Smith
mesh_terms: D018712:Analgesics, Non-Narcotic / Q000008:administration & dosage / Q000494:pharmacology; D000701:Analgesics, Opioid / Q000008:administration & dosage / Q000494:pharmacology; D000818:Animals; D002077:Butorphanol / Q000008:administration & dosage / Q000494:pharmacology; D016292:Procedural Sedation / Q000662:veterinary*; D020927:Dexmedetomidine / Q000008:administration & dosage / Q000494:pharmacology; D004285:Dogs / Q000502:physiology*; D004305:Dose-Response Relationship, Drug; D004452:Echocardiography; D005260:Female; D006325:Heart Atria / Q000000981:diagnostic imaging; D006339:Heart Rate / Q000187:drug effects; D007273:Injections, Intramuscular / Q000662:veterinary; D008297:Male; D012016:Reference Values
chemical_list: D018712:Analgesics, Non-Narcotic; D000701:Analgesics, Opioid; D020927:Dexmedetomidine; D002077:Butorphanol
keywords: Alpha-2 agonists; Butorphanol; Echogenic smoke; Spontaneous echogenic contrast; Valvular insufficiency