Pain Management Flashcards
Why do we want to avoid pain?
- prolongs recovery
- poor or delayed wound healing
- self trauma
- impairs respiratory and cardiovascular function
- reduces food intake
- reduces mobility
- ethical responsibility
What physiological responses are caused by pain?
- Sympathetic NS response
- Increased HR
- Increased RR
- Dilation of bronchi
- Adrenaline release causes cardiac arrhythmias
What is the difference between chronic and acute pain?
Acute pain does not usually outlast the initial painful stimulus, whereas chronic pain does. (chronic pain cane defines as pain lasting longer than 12 weeks)
Define analgesia
Loss of sensitivity to pain or ABSENCE of pain . Only absolute analgesic is a local anaesthetic
Define Hypoalgesia
Reduction of pain
- more accurate term
What is the goal of pre-emptive analgesia
Prevent neuron sensitisation
Describe the physiology of pain
Painful stimulus causes release of inflammatory mediators and activation of nociceptors (pain receptors).
These then transmit pain signals to the CNS via pain pathways. This is then where the perception of pain occurs.
Repeated stimulus of pain pathways can cause heightened sensitivity
What is the aim of analgesia?
To interrupt or modify the pain pathway and block the perception of pain
Define Allodynia
Sensitive to stimuli that would not normally cause pain (i.e. touching an area that isn’t painful but getting a response that would indicate it was!)
Define Hyperalgesia
Greater intensity and duration of pain than would be expected
Describe Methadone
- Full agonist
- licensed for dogs and cats
- Used for moderate to severe pain e.g. spay, fracture
- Provides analgesia and some sedation
Describe Buprenorphine
- Partial agonist
- Reaches analgesic plateau (increasing dose does not increase analgesia)
- For mild to moderate pain e.g. superficial surgeries
What are NSAIDs mostly used for?
- Perioperative pain relief
- Management of chronic pain
- They block
What are side effects of NSAIDs
- Renal
- Prostaglandins maintain glomerular and renal blood flow so NSAIDs may lead to renal dysfunction or failure - GIT
- COX1 responsible for mucus secretion and maintaining blood flow to the gut. NSAIDs may cause gastric ulceration
When are NSAIDs contraindicated?
- Hypotension
- Dehydration
- Pre-existing renal disease
- Liver disease (risk of overdose as metabolised by liver)
- Animals already on steroids or NSAIDs
Give some examples of NSAIDs
- Meloxicam
- Aspirin
- Carprofen
- Paracetamol (TOXIC to cats)
What is the only true painkiller?
Local Anaesthetics - block nociceptive impulses
Give some examples of local anaesthetics
- Bupivicaine
- Mepivicaine
- Lignocaine (lidocaine)
Describe what alpha 2 adrenoreceptor agonists are
Sedative drugs with analgesic effects
- used in lower doses for ONLY analgesia
Give examples of alpha 2 adrenoreceptor agonists
Medetomidine and Dexmedetomidine
What can you use to reverse alpha 2 adrenoreceptor agonists?
Atipamezole
What is Gabapentin used for?
Used to treat neuropathic pain
Describe what ketamine is? and what it does?
Dissociative anaesthetic
- provides somatic analgesia
- used at lower doses for analgesia only
- acts centrally and helps prevent hypersensitivity build up by blocking central sensitisation
What is multi-modal analgesia?
The use of multiple drugs incorporating different pharmalogical actions to produce optimal analgesia
i.e. to interrupt the pain pathway at multiple points)
