Faculty of Veterinary Medicine University of Zagreb
Abstract
A prospective randomized blinded study was conducted on 12 clinically healthy adult dogs of both sexes (mean weight of 18.34 ± 0.78 kg) divided into three groups (n = 4). The animals received 0.4 mg/kg midazolam and 10 μg/kg dexmedetomidine (group A), 0.4 mg/kg midazolam and 20 μg/kg dexmedetomidine (group B) and 0.4 mg/kg midazolam + 20 μg/kg dexmedetomidine + 4 μg/kg fentanyl (group C) intramuscularly, using separate syringes. Ten minutes later Ketamine was administered intravenously in all the groups. A significantly (P<0.05) shorter weak time (onset of sedation) and down time (onset of recumbency) were recorded in animals in group C as compared to the animals of groups A and B. Muscle relaxation was excellent in group C. The pedal reflex was abolished up to 30 min in groups A and B and up to 60 min in group C. Intubation was only possible in groups B and C. The anaesthetic induction dose of ketamine was minimal in group C. Standing recovery time was shortest in the animals of group C. Respiratory rate (RR) decreased significantly (P<0.05) throughout the observation period, but rectal temperature (RT) decreased significantly (P<0.05) towards the end of the observation period in all the groups. Heart rate decreased significantly (P<0.05) in the animals of group B. Mean arterial pressure (MAP) was maintained within the physiological range in all the groups. It was concluded that dexmedetomidine (10 μg/kg)-midazolam-ketamine can produce anaesthesia for about 20 min in dogs. Increasing the dose of dexmedetomidine did not enhance the duration of anaesthesia, but the further addition of fentanyl not only reduced the induction dose of ketamine but also increased the duration of anaesthesia up to 50 min. Dexmedetomidine-midazolam-fentanyl-ketamine can be used for prolonged duration of injectable anaesthesia in dogs.Poduzeto je prospektivno istraživanje na 12 slučajno odabranih klinički zdravih pasa i kuja (prosječne tjelesne mase 18,34 ± 0,78 kg) podijeljenih u tri skupine (n = 4). Životinjama skupine A bio je intramuskularno primijenjen midazolam u dozi od 0,4 mg/kg i deksmedetomidin u dozi od 10 μg/kg. Životinjama skupine B bio je i/m primijenjen midazolam u dozi od 0,4 mg/kg i deksmedetomidin 20 μg/kg, a životinje skupine C primile su i/m 0,4 mg/kg midazolama, 20 μg/kg deksmedetomidina i 4 μg/kg fentanila. Deset minuta nakon toga svim je životinjama intravenski bio ubrizgan ketamin. Značajno (P<0,05) kraće vrijeme smirivanja (nastup sedacije) i vrijeme lijeganja ustanovljeno je u životinja skupine C u usporedbi sa skupinama A i B. Opuštanje mišićja bilo je izvrsno u skupini C. Nožni refleks nestao je nakon 30 minuta u skupinama A i B, a nakon 60 minuta u skupini C. Intubacija je bila moguća samo u životinja skupine B i C. Doza ketamina potrebna za početak anestezije bila je najmanja u životinja skupine C. Vrijeme potrebno za ponovno ustajanje bilo je najkraće u životinja skupine C. Frekvencija disanja značajno se smanjila (P<0,05) u čitavom razdoblju promatranja, dok se rektalna temperatura u svih životinja značajno smanjila (P<0,05) na kraju razdoblja promatranja. Frekvencija bila znatno se smanjila (P<0,05) u životinja skupine B. Srednji arterijski tlak bio je u fiziološkim granicama u svih životinja. Može se zaključiti da kombinacija deksmedetomidin (10 μg/kg)-midazolam-ketamin može u pasa dovesti do anestezije za oko 20 minuta. Povećanje doze deksmedetomidina nije povećalo trajanje anestezije. Ipak, daljnja primjena fentanila ne samo da je smanjila početnu dozu ketamina već je povećala trajanje anestezije na 50 minuta. Deksmedetomidin-midazolam-fentanil-ketamin mogu se rabiti za produženo trajanje injekcijske anestezije u pasa
