Page 21 - BSAVA Guide to Pain Management in Small Animal Practice

BSAVA Guide to Pain Management in Small Animal Practice

VetBooks.ir 1. Provision of intraoperative analgesia. analgesia, the practice of using di erent classes
he second is the principle of multimodal
Although a patient that is ade uately
anaestheti ed cannot by de nition
of analgesic drug in combination to provide more
experience pain, nociception during surgery e ective pain relief while limiting side e ects
will still occur. herefore, provision of from the individual agents. ultimodal analgesia
intraoperative analgesia is imperative to is widely accepted to be best practice in human
prevent upregulation of the pain pathways anaesthesia and analgesia akobsson, 14 . It is
during surgery. more e ective than unimodal analgesia
. he administration of opioid analgesics will techni ues utili ing one class of analgesic drug
increase the sedative e ects of many because the pain pathway is complex and
sedative premedicant drugs including comprises multiple neurotransmitters and
aceproma ine, alpha agonists, and receptors. herefore, analgesia provision using
ben odia epines. Synergistic sedation one class of analgesic drug that acts at one
between opioids and sedatives may allow a receptor or only one component of the pain
lower dose of the sedative premedicant to pathway is unlikely to provide comprehensive
be used, while still maintaining good pain relief. Combining di erent classes of
sedation, which may have cardiovascular analgesic drug often allows lower doses of
and respiratory system bene ts. individual agents to be used, reducing the
. By virtue of the synergistic sedation likelihood of side e ects. or example, using a
local anaesthetic techni ue will usually allow
between opioids and sedative lower doses of systemic opioid drugs to be
premedicants, the administration of administered after surgery, thereby reducing
analgesics as part of premedication concurrent sedation associated with opioid
protocols should allow a lower dose of administration. Combining di erent classes of
hypnotic agent to be re uired for induction analgesic drug may also provide better temporal
of anaesthesia, which may reduce pain relief. or example, NSAI s have a long
cardiovascular and respiratory system duration of action, typically 4 hours, but have a
depression. relatively slow onset of action. In contrast, many
4. pioids have a minimal alveolar concentra parenteral opioids are short acting but have a
tion AC sparing e ect and reduce the uick onset of action, typically in the order of
concentration of inhalant agent re uired to minutes after intravenous in ection. Combining
maintain anaesthesia in dogs and cats e.g. an opioid with an NSAI thereby allows a rapid
Credie et al., 1 . his is likely to lessen onset and long duration of analgesia to be
depression of the cardiorespiratory systems achieved. here is some evidence in veterinary
during anaesthesia. medicine that multimodal analgesia techni ues
provide superior analgesia compared with
Approach to the unimodal techni ues e.g. Brondani et al., 9;
anu o et al., 1 . It is important to make a
administration of distinction between multimodal analgesia and
analgesic agents to polypharmacy. ultimodal analgesia is the
strategic use of di erent classes of analgesic
surgical patients agents to combat di erent underlying pain
mechanisms. herefore, the combinations of
here are a number of principles to consider drugs utili ed should complement each other in
when designing e ective perioperative terms of di ering mechanisms of action to target
analgesic protocols for surgical patients. he di erent parts of the pain pathway. It is also
rst, preventive analgesia, has been described important to note, for example, that combining
above, and is imperative to try and prevent two di erent opioid drugs does not constitute
or limit the magnitude of central and multimodal analgesia because the drugs are
peripheral sensiti ation. from the same class.

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