Continuous infusion in adult females dogs submitted to ovariohysterectomy with midazolam-xylazine and/or medetomidine pre-treated with methotrimeprazine and buprenorphine.
OBJECTIVE
To compare, by continuous infusion of ketamine or medetomidine combined to methotrimeprazine and buprenorphine, ketamine and midazolam, the degree of hypnosis, myorelaxation, anesthetic quality and surgical feasibility through evaluation of possible parametric alterations and recovery quality.


METHODS
20 healthy adult females dogs, aged 3 to 5 years, body weight between 7 and 15 kg, were assigned randomly and homogenously to 2 groups of 10 animals each (n=10), group 1 (G1) and group 2 (G2), respectively. Animals of G1 were subjected to a pre-treatment with intravenous 1.0 mg/kg methotrimeprazine and or 3ì/kg. After 15 minutes, a 5.0 mg/kg ketamine and 0.2 mg/kg midazolam were intravenously injected. Immediately after induction, an anesthetic combination of 0.4 mg/kg/h midazolam, 20 mg/kg/h ketamine and 1.0 mg/kg/h xylazine, was continuously and intravenously administered for 30 minutes. The same techniques were used in G2 except for the substitution of xylazine for 30ìg/kg/h medetomidine.


RESULTS
In G1 there was a 1st and 2nd degree atrioventricular heart block, a longer recovery period and lower quality. In G2 a 1st degree atrioventricular heart block occurred but isolated and ephemeral.


CONCLUSIONS
The continuous infusion method, besides reducing drugs utilization, prevented collateral effects allowing a more tranquil recovery with no excitations, both protocols permitted the surgical procedure (ovary-hysterectomy) bringing about a reduction in hypnosis and an accentuated myorelaxation. Xylazine and medetomidine showed a similar pharmacodynamic behavior but with different clinical aspects. The electrocardiographic alterations observed in G2 and in a lower degree in G1 must be well studied. Describers: dogs, ketamine, methotrimeprazine, medetomidine, midazolam and xylazine.
Silva
Fernando do Carmo
Fdo C
Faculty of Medicine, UNESP, Botucatu, São Paulo, Brazil.
Hatschbach
Eduardo
E
Lima
Alfredo Feio da Maia
AF
Carvalho
Yuri Karaccas de
YK
Massone
Flavio
F
D000316:Adrenergic alpha-Agonists / Q000008:administration & dosage*; D000701:Analgesics, Opioid / Q000008:administration & dosage; D019162:Anesthetics, Combined / Q000008:administration & dosage; D018686:Anesthetics, Intravenous / Q000008:administration & dosage*; D000818:Animals; D002047:Buprenorphine / Q000008:administration & dosage; D004285:Dogs; D018492:Dopamine Antagonists / Q000008:administration & dosage; D004353:Drug Evaluation, Preclinical; D005260:Female; D006993:Hypnotics and Sedatives / Q000008:administration & dosage*; D007044:Hysterectomy / Q000379:methods* / Q000592:standards; D007260:Infusion Pumps; D020926:Medetomidine / Q000008:administration & dosage; D008728:Methotrimeprazine / Q000008:administration & dosage; D008874:Midazolam / Q000008:administration & dosage; D023421:Models, Animal; D010052:Ovariectomy / Q000379:methods* / Q000592:standards; D011897:Random Allocation; D014991:Xylazine / Q000008:administration & dosage
D000316:Adrenergic alpha-Agonists; D000701:Analgesics, Opioid; D019162:Anesthetics, Combined; D018686:Anesthetics, Intravenous; D018492:Dopamine Antagonists; D006993:Hypnotics and Sedatives; D014991:Xylazine; D002047:Buprenorphine; D008728:Methotrimeprazine; D020926:Medetomidine; D008874:Midazolam