1. Acute pain emergencies
Sydney
Broome
Fremantle

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What is pain?
Pain is an unpleasant sensory & emotional experience associated with actual or potential tissue damage
Subjective, multidimensional, whole-person experience
Pain is what the person-in-pain says it is
Pain always occurs in a ‘context’
-bio-medical-psycho-social-environmental
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Nociception
Processing of noxious stimuli in the nervous system
Energy of tissue damage → electro-chemical nerve signals
Chemical (inflammatory soup), mechanical, thermal
Pain & nociception are not the same thing
Nociception is the sensory processing bit (brain input)
Pain is the sensory & emotional experience (brain output)
Nociception is major (but not exclusive) pain stimulus
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NASTI pain stimuli
Nociception
Neuropathy
Anxiety (fear)
Stress (flu)
Threat (of any kind)
Information-scrambling (LA block, mirrors)
EJ Visser Churack Chair UNDA 2017 copyright

5. Terminator II-Judgment Day (1991)
Nociception
vs pain
Terminator II-Judgment Day (1991)
John Connor
“Does it hurt when you get shot?”
The Terminator
“I sense injuries…
The data could be called pain.”
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Acute
pain
Alarm system pain
Pain of recent onset & limited duration (<3M)
Clear relationship to injury or disease
Physiological pain
Nociceptive, inflammatory
Protective & adaptive
Pain ≈ amount of tissue damage
Pain improves with healing
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Chronic
Pain
Pain > time of normal tissue healing (≥3M)
Alarm malfunction pain
Alarm keeps ringing when there’s no emergency
Pathological pain
No protective function
Pain ≠ amount of tissue damage
Breakdown in pain modulation
EJ Visser Churack Chair UNDA 2017 copyright

8. Pain as Nature’s alarm Acute pain = ‘tissue damage emergency’
Pain (nociception) has protected Earth’s life-forms from damage for millions of years
Evolutionary survival advantage
Highly preserved in phylogeny

9. EVOLUTION
Reflexes
Nociception
Pain

10. Pain alarm Pain motivates us to avoid tissue damage in real time
Acute stress response
Pain behaviours

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Pain behaviours
Signals ‘distress’
Defensive: fight & flight, feign & freeze (play-dead)
Protective: splinting, limping, rubbing
Adaptive: crawl to cave, call an ambulance
Social signalling: facial expressions, crying, swearing
‘I need help’, ‘stay away from danger’
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12. Pain
alarm
Pain conditions us (and others in our social group) to avoid future tissue damage
Learn from our mistakes
Especially in childhood
Nocebo response

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Pain behaviours
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Distress
behaviours
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NASTI pain stimuli
Nociception
Anxiety (fear) S T I
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16. Fear (anxiety) is also an alarm
Pain ≈ fear (anxiety)
Both protect tissues from damage
Shared facial expressions & behaviours
Shared neurochemistry
-serotonin, nor-adrenaline
Shared neuroanatomy & function
Anxiety = chronic pain & disability
-catastrophizing, hypervigilance
-3Ps: panic, PTSD, phobias
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17. EVOLUTION
Reflexes
Nociception
Pain
Fear

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Tip no. 1
Anxiolysis?
If analgesia is not working, consider anxiolysis
EJ Visser Churack Chair UNDA 2017 copyright

19. Biphasic acute pain response
to injury
Fight or
Flight
Hyperalgesia
Analgesia
Rest and recover
Hyperalgesia ‘conditions’ (teaches)
the cave man to avoid the same
tissue damage (tiger) in the future
EJ Visser Churack Chair UNDA 2017 copyright
Simonnet & Rivat Neuroreport 2003

20. Emergency analgesia
(‘damping’)
Allows ‘flight’

21. Central Sensitization
Emergency hyperalgesia
(‘amplifier’)
Central Sensitization
Increased nociceptive output for a given input
‘Capacitor’
(memory)
NMDA
‘Amplifier’ Hz
lllllllllllllllllllll 50Hz
Dorsal horn
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22. Pain (nociceptive) modulation
Inhibitory Control
“Damping”
Central
Sensitization
“Amplifier”
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23. Why treat acute pain optimally?
Humanitarian (basic human right)
Modulates acute stress response
Facilitates rehabilitation & mobilization
Reduces acute-to-chronic pain transition
Reduces psychological distress (PTSD)
(fight-or-flight)
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24. Acute pain pain Acute-to-chronic pain Chronic
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25. Principles of acute pain
management
Treat FIRST
Ask questions later (3P’s)
Pain type (nociceptive, inflammatory, neuropathic, visceral, cancer)
Pathology (cause) (pain is an alarm after all!)
Problems
-red flags (T.I.N.T)
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26. Acute musculoskeletal pain
Red flags
Acute musculoskeletal pain
T.I.N.T
Tumour
Infection/Inflammation
Neurological
Trauma
Questions to ask
COAST
Cancer, Osteoporosis, Age, Steroids, Trauma

27. Need to get analgesic into effector site (CNS) ASAP
Treat acute pain
FAST
Need to get analgesic into effector site (CNS) ASAP

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Treat acute pain
FAST
Intravenous
Inhalational
-nitrous oxide
-methoxyflurane
Transmucosal
s/c
Oral (5 half-lives) 1/24 prn
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29. Multimodal
analgesia
‘The rational use of two-or-more analgesics to improve pain control and/or reduce adverse effects’
Opioids (tramadol, tapentadol)
Paracetamol IV, po (not PR)
NSAIDs & ‘COXIBS’
-oral rapid-acting NSAIDs ARE more effective (level I)
-IV parecoxib, IV ibuprofen, PR NSAIDs
Duo-analgesics (combinations) are more effective
-e.g. paracetamol/tramadol, paracetamol/ibuprofen

30. Analgesia league table Combos work better
NNT
Etoricoxib 120 mg
Celecoxib
Ibuprofen
Paracetamol ibuprofen
Paracetamol tramadol
Panadeine forte 60/
Paracetamol
Tramadol
Codeine

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Multimodal
analgesia
Adjuvant analgesics
-pregabalin
-clonidine (neuropathic pain, withdrawal, anxiety)
-local anaesthesia & regional techniques (best)
PHYSICAL
-splints, hot & cold packs, TENS, acupuncture, massage
PSYCHOLOGICAL
-information, distraction, music, VR, mindfulness, hypnosis
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32. One-four-the-road rule
Tip no. 2
Analgesia prescribing post injury or surgery
One-four-the-road rule
1 opioid
4/24 prn (max)
≤ 4 x daily (QID)
≤ 4 days (≤ 20 tabs) Rx
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33. Is the pain ‘out-of-the-box?’
Tip no. 3
Difficult pain problem?
Is the pain ‘out-of-the-box?’
Red flags?
Yellow flags?
Complication of surgery?
Complication of analgesia?
Chronic pain?
Bad (cluster B)
Anxiety
Drugs

34. GON, LON blocks
2 mls 0.75% ropivacaine + 10 mg kenacort

35. Diffusion intercostal block
Hit the mid point of rib deliberately
Don’t need to go into the intercostal space
3 mls 0.75% ropivacaine

36. ‘Treat first ask questions later’ (won’t affect diagnosis)
Acute abdominal pain
‘Treat first ask questions later’ (won’t affect diagnosis)
IV opioid (+/- IV paracetamol, +/- parecoxib)
Red flags & yellow flags-drug seeking
Renal colic
-TENS
-IV parecoxib & IV paracetamol
-PR NSAIDs & PO paracetamol
-IV ondansetron
-IV opioid titration
-pethidine (no benefit) (Level II)
-anti-spasmodics, diuresis (no benefit) (Level II)

37. Acute back pain Red flags (T.I.N.T) & yellow flags
Reassurance, information, keep moving
Heat packs
Celecoxib mg bd for ≤4 days
Combination paracetamol w/tramadol or codeine prn
Short-term IR opioid (oxycodone) (≤4 days)
Baclofen (severe muscle spasms, avoid diazepam)
Trigger points, acupuncture, spinal manipulation

38. Acute neuropathic pain
Herpes zoster, radiculopathy, neuropathy, TN
Tramadol, tapentadol, oxycodone (Level I)
TCA or pregabalin (level I)
Clonidine
Topical agents
-menthol 4%, capsaicin 0.075%
-EMLA, lignocaine 5% patches (e.g. healed acute zoster)
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Acute pain Mx tips
Shoot (treat pain) first, ask questions later
Always check for red FLAGS (T.I.N.T)
Use fasted analgesia mode possible (IV, inhalation, buccal, po)
Use multimodal analgesia (LA techniques are best)
Duo-combination analgesics are more effective
Rapidly-absorbed oral NSAIDs are more effective
Is the pain ‘out-of-the-box’ (worse than expected)?...
Then check if there are any red flags or yellow flags?
Pain & fear (anxiety) are the same thing…
So, if analgesia doesn’t work, consider anxiolysis
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Questions?
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41. Acute migraine & headache
Red flags (T.I.N.T) (headache: new, usual, thunderclap?)
Drugs taken already?
High flow oxygen (cluster)
Cranial TENS (trial)
IV fluids
Triptans
PO aspirin or IV parecoxib or PR indomethacin and…
IV metoclopramide or prochlorperazine or chlorpromazine
IV dexamethasone
Occipital nerve blocks
Acupuncture
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42. Acute radicular leg pain Red flags (T.I.N.T) Likely neuropathic pain?
Tramadol IR, SR or tapentadol
Pregabalin
Baclofen (spasms)
Oxycodone IR
Transforaminal epidural steroid injection
Oral steroids?
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43. Vitamin C 1000 mg/d for 6 weeks Reduces the risk of CRPS
Tip no. 4
All distal limb injuries
Vitamin C 1000 mg/d for 6 weeks Reduces the risk of CRPS
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