Uso da dexmetomidina isolada ou em associação com cetamina ou cetamina s (+) por via oral transmucosa em cães: eficácia sedativa, avaliação de parâmetros cardiorrespiratórios e hemogasométricos

Abstract

The use of pre-anesthetic medication (MPA) is a non-obligatory, but often important, part of a multimodal anesthetic protocol. The benefits include a reduction in patient stress and anxiety, a reduction in the dose of general anesthetics, a reduction in adverse effects and a reduction in risks to the anesthetic team. Unconventional systemic routes of administration, such as oral transmucosal (OTM) or intranasal (IN), are gaining importance in veterinary medicine, due to the advantages they offer in relation to intramuscular (IM) and intravenous (IV) treatments. The study described below was approved by the Ethics Committee for the Use of Animals at the Federal University of Santa Maria (UFSM). 18 male dogs were selected, of no defined breed and considered healthy through physical examination and hematological tests. Prior to the procedure, patients underwent solid and water fasting for 8 and 2 hours, respectively. Subsequently, they were randomly allocated into 3 groups, namely: dexmedetomidine (GD), at a dose of 10 μg.kg-1, racemic ketamine + dexmedetomidine group (GDC), at a dose of 20 mg.kg-1 and 10 μg.kg -1, respectively and the ketamine S (+) + dexmedetomidine (GDCS) group, at a dose of 10 mg.kg-1 and 10 μg.kg-1, respectively, all medications were administered OTM. To evaluate the sedation score, a dog sedation scale developed by Grint et al., (2009) was used. The evaluations began 15 minutes after the application of the treatments and subsequently continued every 10 minutes until the patients fully recovered. Even so, we evaluated the parameters of HR, ƒ, TRºC, SAP, mucosal color and TPC at the same time intervals described above. In addition, three blood samples were collected from the jugular vein for venous blood gas analysis, at the following moments: C1, carried out 20 minutes before the application of MPA; C2, after 30 minutes of MPA application and C3, carried out after the patient has fully recovered. Drug administration via the transmucosal route was well tolerated, however, adverse effects were observed in 50% of animals in GD, 83% without GDC and 83% without GDCS. Regarding the physiological configurations evaluated during sedation, differences can be observed in the HR values of the GDC and GDCS in relation to the GD group and also between moments of the GD. Regarding the sedation score, a higher score was observed as well as a longer sedative effect time in GD, when compared to GDC and GDCS. Regarding the hemogasometric evaluation, there was no difference within groups or between groups, in the three times evaluated. It was concluded that the association of dexmedetomidine and ketamine or S (+) ketamine via OTM did not provide adequate sedation in dogs when compared to dexmedetomidine alone. No relevant blood gas changes were caused by any of the treatments.