STUDY ON DEXMEDETOMIDINE- BUTORPHANOLMIDAZOLAM- KETAMINE ANAESTHESIA IN CAPTIVE SLOTH BEARS (MELURSUS URSINUS)
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Date
2019-08-20
Authors
Journal Title
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COLLEGE OF VETERINARY AND ANIMAL SCIENCES, POOKODE WAYANAD
Abstract
Six adult, apparently healthy, captive sloth bears (Melursus ursinus) of
Bannerghatta Bear Rescue Centre of Wildlife SOS, Bangalore, which were
anaesthetized using a drug combination of dexmedetomidine, butorphanol,
midazolam and ketamine at dose of 4 µg/kg, 0.2 mg/kg, 0.05 mg/kg and 4 mg/kg
respectively, for routine clinical healthcare procedures and checkups, were studied
to observe, record and evaluate the anaesthetic effects of the drug combination.
The injectable drug combination provided profound sedation with plane 2
or 3 of stage III anaesthesia, to facilitate invasive and non- invasive general
healthcare procedures. Time taken for induction of anaesthesia in five animals was
13.60 ± 4.33 min. One animal stood sedated, with low head carriage and ataxia at
21st min of initial administration of the drug combination, but responded when
approached. Hence, one half of initial dose of midazolam and ketamine was
administered at 28th min, with which anaesthesia was induced at 52nd min. The
sedation achieved with the injectable drug combination was reliable and profound.
Pedal, palpebral and corneal reflexes were absent following induction with
the injectable drug combination and during maintenance with midazolamketamine top up. The eyeballs were medially positioned and the pupil of all
animals was constricted.
Duration of anaesthesia achieved with the injectable drug combination was
70.67 ± 26.06 min. To prolong the period of anaesthesia, the first top up of
midazolam and ketamine provided anaesthesia for 30.80 ± 11.34 min, that of
second top up for 25.33 ± 4.16 min, and that of third top up for 19.0 min.
Following extubation of endotracheal tube, the animals lifted their head in
4.67 ± 3.08 min, regained righting reflex in 16.83 ± 9.60 min, and stood balanced
in 29.0 ± 11.01 min. The recovery was smooth and uneventful.
Heart rate and rate of respiration was found reduced following induction
with the injectable drug combination and during maintenance with the midazolamketamine top up. Rectal temperature and peripheral haemoglobin saturation of
oxygen were near normal range. The mean non-invasive blood pressure was in the
higher range. Capillary refill time was normal. The end- tidal carbon dioxide
tension was near normal range. Sinus bradycardia was noticed in the
electrocardiogram. The blood gases, electrolytes and biochemical values did not
show significant changes and variations from normal.
It could be concluded that dexmedetomidine- butorphanol- midazolamketamine combination at the dose of 4 µg/kg, 0.2 mg/kg, 0.05 mg/kg and 4 mg/kg
respectively, provides profound sedation with plane 2 or 3 of stage III anaesthesia
in sloth bears, to facilitate invasive and non- invasive general healthcare
procedures, without compromising haemodynamic and respiratory functions. The
duration of surgical anaesthesia could be reliably prolonged with the top up of
midazolam and ketamine.
Description
Six adult, apparently healthy, captive sloth bears (Melursus ursinus) of
Bannerghatta Bear Rescue Centre of Wildlife SOS, Bangalore, which were
anaesthetized using a drug combination of dexmedetomidine, butorphanol,
midazolam and ketamine at dose of 4 µg/kg, 0.2 mg/kg, 0.05 mg/kg and 4 mg/kg
respectively, for routine clinical healthcare procedures and checkups, were studied
to observe, record and evaluate the anaesthetic effects of the drug combination.
The injectable drug combination provided profound sedation with plane 2
or 3 of stage III anaesthesia, to facilitate invasive and non- invasive general
healthcare procedures. Time taken for induction of anaesthesia in five animals was
13.60 ± 4.33 min. One animal stood sedated, with low head carriage and ataxia at
21st min of initial administration of the drug combination, but responded when
approached. Hence, one half of initial dose of midazolam and ketamine was
administered at 28th min, with which anaesthesia was induced at 52nd min. The
sedation achieved with the injectable drug combination was reliable and profound.
Pedal, palpebral and corneal reflexes were absent following induction with
the injectable drug combination and during maintenance with midazolamketamine top up. The eyeballs were medially positioned and the pupil of all
animals was constricted.
Duration of anaesthesia achieved with the injectable drug combination was
70.67 ± 26.06 min. To prolong the period of anaesthesia, the first top up of
midazolam and ketamine provided anaesthesia for 30.80 ± 11.34 min, that of
second top up for 25.33 ± 4.16 min, and that of third top up for 19.0 min.
Following extubation of endotracheal tube, the animals lifted their head in
4.67 ± 3.08 min, regained righting reflex in 16.83 ± 9.60 min, and stood balanced
in 29.0 ± 11.01 min. The recovery was smooth and uneventful.
Heart rate and rate of respiration was found reduced following induction
with the injectable drug combination and during maintenance with the midazolamketamine top up. Rectal temperature and peripheral haemoglobin saturation of
oxygen were near normal range. The mean non-invasive blood pressure was in the
higher range. Capillary refill time was normal. The end- tidal carbon dioxide
tension was near normal range. Sinus bradycardia was noticed in the
electrocardiogram. The blood gases, electrolytes and biochemical values did not
show significant changes and variations from normal.
It could be concluded that dexmedetomidine- butorphanol- midazolamketamine combination at the dose of 4 µg/kg, 0.2 mg/kg, 0.05 mg/kg and 4 mg/kg
respectively, provides profound sedation with plane 2 or 3 of stage III anaesthesia
in sloth bears, to facilitate invasive and non- invasive general healthcare
procedures, without compromising haemodynamic and respiratory functions. The
duration of surgical anaesthesia could be reliably prolonged with the top up of
midazolam and ketamine.