Page 135 - Canine Lameness

8.3 Sedation rotocols 107

Box 8.2 DJA Protocol A
Step 1 – Sedative agent is administered intravenously – dexmedetomidine (0.5 mg/ml) given
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2
IV at a dose of 250 mcg/m .
Step 2 – Intra-articular anesthetic is instilled in the target joint.
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Step 3 – Reversal agent is administered intramuscularly immediately after intra-articular anes-
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thetic is administered – atipamezole (5.0 mg/ml) is administered IM at a volume (ml) that is
the same as the preceding dose volume of dexmedetomidine.
Step 4 – Lameness evaluation is performed seven minutes after reversal agent (atipamezole)
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is administered.

with an antagonist agent. These aspects make it well suited for DJA. Available studies were per-
formed with medetomidine; however, currently clinicians in North America are more likely to
have access to dexmedetomidine. The recommended steps for DJA with an α₂‐adrenergic receptor
agonist are listed in Box 8.2.

8.3.2 Sedation Protocol B: Sedation with a Neuroleptanalgesic and Opiate
The use of acepromazine with an opiate has also been investigated and serves as a good option for
use with DJA. This method of sedation is used for light‐to‐moderate sedation and analgesia while
still allowing the patient to ambulate. Since sedation is less effective, more physical restraint was
needed in one study (Van Vynckt et al. 2012b). Therefore, we prefer to use protocol A unless there
are contraindications for the use of an α₂‐adrenergic receptor agonist. Unlike sedation protocol A,
there is no reversal agent administered. It is possible that stressed or anxious animals may require
a higher sedative dose; however, Van Vynckt et al. (2012b) found the dose range in the steps listed
in Box 8.3 suitable for DJA.
Currently, our understanding of how other sedatives affect lameness in dogs is limited to the
protocols discussed above. It is possible that other protocols (such as use of Propofol or local anes-
thetics in addition to sedation) may be equally useful. However, the degree of effect and more
importantly a means to account for that effect in our clinical interpretation is lacking. For example,
if a local anesthetic is used, it could result in a change in lameness because of diffusion (and pro-
viding local anesthesia) into the extra‐articular structures. This is not to say that other sedatives or
combinations of sedatives are not appropriate for DJA, just that their effect on lameness interpreta-
tion is currently unknown. Therefore, it is recommended that clinicians use the tested and studied
methods.

Box 8.3 DJA Protocol B

Step 1 – Sedative agent is administered intravenously – acepromazine (0.01–0.02 mg/kg IV)
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and methadone (0.1–0.2 mg/kg IV).
Step 2 – Intra-articular anesthetic is instilled in the target joint.
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Step 3 – Lameness evaluation is performed two minutes after intra-articular anesthetic is
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administered.