Peroperative Pain Management Flashcards
What are the 3 things that intraoperative and antinociception prevents?
1) wind up and sensitisation
2) nociception and sympatho adrenal outflow
3) reflex movement
What are the four things that pre-operative pain management can achieve?
1) facilitates preparation and examination of animals
2) reduces the risk of personal injury
3) reduces induction problems
4) smoothes induction in horses
What are the 7 things that pain can cause in a recovering animal?
1) impairs appetite
2) hypermetabolic state= -ve energy and protein balance
3) immunosuppression
4) accelerates catabolism
5) prevents sleep
6) prevents recovery
7) impairs ventilation
What are the 7 things that effective pain management achieves?
1) improves animal’s activity
2) simplifies general nursing
3) allows repositioning- pressure sores/muscle damage/lung congestion
4) allows wound inspection/ redressing
5) reduces vocalisation, better conditions
6) improves recovery in horses (traumatic fracture)
7) prevents abortion
How does sensitisation arise?
trauma= phospholipase A2=arachidonic acid= COX and Lipoxygenase= sensitisation soup. Which increases the sensitivity of the n fibres so they fire more frequently= peripheral sensitisation. This increases frequency of sunbstantia gelatinosa cells= centra sensitisation.
What are the components of the sensitising soup?
Lipoxygenase acts on arachidonic acid= Vasodilation, inc. vasc. perm. and leukocyte invasion.
COX= PgG2 and PgH2=LTs, TXs, PGs, Prostacyclins, seratonin, substance P and bradykinin. = peripheral sensitisation.
What 4 changes occur in cell of the SG after central sensitisation?
1) adrenoreceptor induction
2) gene expression
3) axonal sprouting
4) NMDA receptor proliferation
Why is NMDA activation the most important?
It can be prevented by ketamine.
The gene changes take weeks to mature but what are the 4 things that will be experienced?
1) post injury pain
2) hyperalgesia- more painful than before, sensitisation
3) allodynia- non noxious= pain
4) neuropathic pain- “phantom limb”
What happens if sensitisation is prevented?
There is no post operative pain.
What do general anaesthetics not do?
they do not prevent sensitisation or prevent post-op pain
What are the four clinical strategies that optimise peri-operative comfort?
1) pre-emptive analgesia (PEA)
2) Polymodal pain therapy (PMPT)
3) Partial intravenous anaesthesia (PIVA)
4) Prolonged post-operative pain therapy (PPOT)
What is Pre-emptive analgesia?
Giving analgesics before surgery which prevents the sensitising soup being formed as it is being formed. Give local anaesthetic to block promotion of central sensitisation, block central sensitisation by spinal LAs e.g ketamine
What is polymodal pain therapy?
Combination of several drug classes to provide total analgesia by synergistic drug effects while avoiding adverse effects as they are all low dose.
What are the combination of drug classes that may be used in polymodal pain therapy?
a2 agonist, LAs, NSAIDS, Opioids, NMDA antagonist
