Page 25 - BSAVA Guide to Pain Management in Small Animal Practice

BSAVA Guide to Pain Management in Small Animal Practice

VetBooks.ir administration of lidocaine systemically to small suggesting that doses higher than 1 g kg h
animals. Studies have investigated the
might be needed to provide signi cant
analgesia in the absence of other analgesic
antinociceptive e ects of a lidocaine CRI in
dogs undergoing surgery and found con icting drugs van ostrom et al., 11 . his study also
results, with one study showing that lidocaine clearly showed that it is not possible to obtain
blunted autonomic responses to surgery analgesia from alpha agonists without
rtega and Cru , 11 , and another showing concurrent sedation. Consideration must be
no e ect of lidocaine on autonomic responses given to the cardiovascular e ects of alpha
Columbano et al., 1 . Anecdotally, lidocaine agonists when deciding whether to use even a
is reported to be e cacious in the management low dose CRI in individual patients because the
of visceral pain although there is limited cardiovascular e ects are still apparent.
evidence to support this view. oses of Infusions of alpha agonists will also increase
g kg min preceded by a loading dose of urine production; therefore, bladder
mg kg administered over 1 minutes are management taking dogs outside fre uently to
recommended in dogs; be aware that lidocaine toilet or expressing the bladder is important in
will reduce the AC of the inhalant agent so dogs that receive an alpha agonist CRI.
depth of anaesthesia should be monitored
carefully when lidocaine is administered during Ketamine
surgery. Lidocaine infusions are not etamine is widely used as part of in ectable
recommended for analgesia in cats due to anaesthesia protocols and will contribute to
negative e ects on the cardiovascular system perioperative analgesia through antagonism of
Pypendop and Ilkiw, . the N methyl aspartate receptor. ore
recently, the analgesic e ects of
Alpha-2 agonists subanaesthetic doses of ketamine have been
Alpha agonists such as medetomidine and recogni ed Laskowski et al., 11; ang et al.,
dexmedetomidine are widely used for 14 , whereby ketamine is administered as a
premedication and as such contribute to CRI during surgery and postoperatively at
perioperative analgesia. owever, the analgesia doses ranging from 1 g kg min. A few
from clinical doses of alpha agonists is studies have been conducted in dogs
relatively short 1 g kg dexmedetomidine investigating the analgesic e ects of low dose
provides analgesia for approximately 4 ketamine administered by CRI and found
minutes ; therefore, dexmedetomidine or variable results about the e cacy of this
medetomidine must be given by a CRI to intervention. agner et al. investigated
provide sustained analgesia. ne study has the analgesic e ects of 1 g kg min
investigated the postoperative analgesic e ects ketamine administered intraoperatively
of dexmedetomidine given by CRI in dogs after followed by g kg min ketamine
invasive surgery and showed similar analgesia postoperatively in dogs undergoing forelimb
was provided by a dexmedetomidine CRI at amputation and found that pain scores were
1 g kg h or morphine .1 mg kg h Valtolina signi cantly lower in dogs that received
et al., 9 . owever, a signi cant number of ketamine compared with a group that did not
dogs in both groups re uired rescue analgesia receive a ketamine CRI. owever, the
with morphine highlighting the importance of di erence in pain scores was numerically small
pain scoring with any analgesic regimen. An and the biological relevance of this di erence
experimental study in dogs compared the can be uestioned. In contrast, Sarrau et al.
sedative and analgesic e ects of 7 found no e ect on postoperative
dexmedetomidine alone using a analgesic re uirements between dogs
neurophysiological model and found that doses undergoing mastectomy receiving either a
of g kg h dexmedetomidine were high dose or low dose ketamine CRI and a
re uired to provide analgesia in this model, control group that did not receive ketamine. In

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