CONTINUOUS RATE INFUSION ANAESTHESIA WITH DEXMEDETOMIDINEMIDAZOLAM-KETAMINE-LIGNOCAINE IN DEXMEDETOMIDINEBUTORPHANOL-MIDAZOLAM-KETAMINE ANAESTHETISED DOGS
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Date
2019-12-11
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COLLEGE OF VETERINARY AND ANIMAL SCIENCES, POOKODE WAYANAD
Abstract
Six adult dogs of different breeds and ages, belonging to eithersex and categorised
as ASA class I or II, which were posted for various elective soft tissue and orthopaedic
surgical procedures in the Department of Surgery and Radiology, College of Veterinary
and Animal Sciences, Pookode, Wayanad, were anaesthetised using a combination of
dexmedetomidine @ 5 µg/kg body weight, butorphanol @ 0.2 mg/kg body weight,
midazolam @ 0.2 mg/kg body weight and ketamine @ 5 mg/kg body weight, given
intramuscularly. Following induction, the animals were intubated and connected to the
circle system of anaesthetic machine to provide oxygen. Thereafter, a loading dose of 2%
lignocaine intravenous preparation was administered @ 2 mg/kg body weight,
intravenously. Following the loading dose of lignocaine, anesthesia was maintained using
a continuous rate infusion of dexmedetomidine (@ 2 µg/kg/h), midazolam (@ 3
µg/kg/min), lignocaine (@ 50 µg/kg/min) and ketamine (@ 40 µg/kg/min). The induction
was smooth, with no signs of anxiety and no laryngeal reflex, allowing easy intubation in
7.33 ± 3.72 min. The maintenance of anaesthesia was excellent. Additional top up
injectable drugs or inhalant agents were not required, throughout the surgeries. The eyeballs were positioned ventro-medially in all six animals studied. Heart rate and rate of
respiration were found decreased following induction. End tidal carbon dioxide values
were initially high, and eucapnia was maintained using manual assisted ventilation, till
the effects of opioid weaned off. The invasive and non-invasive blood pressure values
were initially high, which slowly dropped down towards the normal physiological range.
A decrease in rectal temperature was observed. The blood gases, electrolytes and
haematological values did not show any significant variation from their normal reference
values. Serum glucose values were observed to be significantly high. Following cessation
of the continuous rate infusion, the animals rejected the endotracheal tube in 42 ± 9.87
minutes. The recovery was smooth and uneventful. From the study, it is concluded that
dexmedetomidine-butorphanol-midazolam-ketamine combination intramuscular @ 5
µg/kg, @ 0.2 mg/kg, @ 0.2 mg/kg and @ 5 mg/kg respectively, followed by an
intravenous loading dose of lignocaine @ 2 mg/kg and a continuous rate intravenous
infusion of dexmedetomidine-midazolam-lignocaine-ketamine @ 2 µg/kg/h, 3
µg/kg/min, 50 µg/kg/min and 40 µg/kg/min respectively, in normal saline, effectively
maintains anaesthesia for various soft tissue and orthopaedic surgeries.