PEREIRA, S. A. R. S.; http://lattes.cnpq.br/7633009821868753; PEREIRA, Sóstenes Arthur Reis Santos.
Resumo:
The objective was to evaluate the quality of continuous intravenous anesthesia promoted by
the tiletamine-zolazepam combination, in rabbits and bitches pre-medicated with
acepromazine. Six rabbits and eight bitches weighing 2.5±0.3 and 13.7±1.9 kg, respectively,
were used. The animals were premedicated with acepromazine (0.1 mg/kg) and, after 15
minutes, intravenous induction of 2 mg/kg bolus of the tiletamine-zolazepam combination,
followed by continuous intravenous infusion of these drugs at a dose of 10 mg/kg/h (rabbits)
and 2 mg/kg/h (bitches), for 60 minutes. The parameters that were measured in all animals,
before pre-medication (M-15), before induction (M0) and at 5, 10, 20, 30, 40, 50 and 60
minutes after the continuous infusion (M5, M10, M20, M30, M40, M50 and M60) were as
follows: electrocardiography (ECG), heart rate (HR), mean arterial pressure (MAP),
respiratory rate (RR) and body temperature (BT), rabbits were still measured 90 minutes after
infusion (M90). Arterial hemogasometry was performed at moments M-15, M0, M5, M30,
M60 and M90 in rabbits, and at moments M-15, M0, M30 and M60 in bitches. An electrical
stimulator was used to evaluate the degree of analgesia. We also evaluated the myorelaxation
and the quality of the anesthetic recovery, classifying these parameters as: excellent, good and
bad. The anesthetic recovery time was recorded in minutes. Rabbits: MAP decreased
significantly after M-15. RR decreased significantly in M20, M30 and M50. Hypothermia did
not occur. There was no significant difference regarding the electrocardiographic parameters,
HR, PaCO2, HCO3
-, TCO2, EB and analgesia. PaO2 and SaO2 in M5 were lower than in M-15,
but without occurrence of hypoxemia. The myorelaxation and the quality of the anesthetic
recovery were considered excellent. The recovery period was 69.3 ± 19.3 minutes. Bitches:
HR increased significantly at time M10 in relation to M-15, and at moments M5, M10, M40
and M50 in relation to M0. MAP decreased significantly in M20 and M30 compared to
baseline. BT decreased significantly in M50 compared to M0, but no hypothermia was
observed. RR showed a significant reduction at moments M5, M10 and M20 in relation to M-
15, and in M5 and M10 in relation to M0, and bradypnoea was observed during the first 20
minutes after anesthetic induction. Significant decreases in the PR interval at moments M10,
M40 and M50 were observed in relation to M-15. The R wave amplitude showed a significant
decrease in M20 compared to M-15. In the other ECG parameters, there was no significant
difference between the moments evaluated. Hemogasometric parameters and analgesia did not
present significant alterations. The myorelaxation and the quality of the anesthetic recovery
were considered excellent. The recovery period was 15.1±7.7 and 45.5±23.1 minutes.
Continuous intravenous administration of tiletamine-zolazepam in rabbits and bitches
premedicated with acepromazine promoted intense myorelaxation and excellent anesthetic
recovery, however, in rabbits, it produced hypotension, transient hypoxemia and mild
analgesia, and in bitches it produced transient respiratory depression and moderate analgesia.