Transcript Acute Pain - Health Education East Midlands VLE (Moodle)

Principles of Acute Pain
Management
29.9.10
Rik Kapila
What this talk isn’t….
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A pharmacology lecture
A physiology lecture
Comprehensive
What this talk is ( I hope!)….
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An overview
Relevant
Enlightening
Interesting
An opportunity
What is pain?
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“An unpleasant sensory and emotional
experience arising from actual or potential
tissue damage or described in terms of such
damage”.
International Association for the Study of Pain
Perhaps more usefully…
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“whatever the experiencing person says it is,
existing whenever he says it does."
Margo McCaffrey 1968
Epictetus (55-135 A.D)
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‘It is not death or pain
that is to be dreaded
but the fear of pain or
death’
Lance Armstrong (1971- present)
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‘pain is temporary –
quitting lasts forever’
Saint Augustine of Hippo (354-430)
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‘the greatest evil is
physical pain’
Does pain matter?
Cardiovascular
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Tachycardia
Hypertension
Increased myocardial
oxygen consumption
Myocardial ischaemia
Respiratory
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Decreased lung volume
Atelectasis
Decreased cough
Sputum retention
Infection
Hypoxia
Gastrointestinal
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Decreased gastric
motility
Decreased bowel
motility
Ileus
Genitourinary
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Urinary retention
Metabolic
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Increased catabolic
hormones
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Cortisol
Glucagon
Growth hormone
Reduced anabolic
hormones
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Insulin
Testosterone
Psychological
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Anxiety
Fear
Sleep disturbance
Depression
Distressing for patient,
family and staff
Chronic Pain after Surgery
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Not fully understood
Worse after some surgery than others
Aggressive acute management may reduce
incidence of chronic problems
But more of that later….
This is why pain matters
Endogenous morphine
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1975 endorphin
enkephalin
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Dynorphin
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synthesised in pituitary
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Receptors in the
peri-aqueductal gray matter
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Endogenous morphine
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Responsible for “hedonistic tone”
Increase descending inhibition in spinal cord
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Increased release in:
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happiness
touch / massage
sex
exercise
hypnosis / relaxation
–
placebo effect -anticipation of the above
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Endogenous morphine
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Increased release in:
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happiness
Increase descending inhibition in spinal cord
touch / massage
sex
exercise
hypnosis / relaxation
placebo effect -anticipation of the above
 Reversed
by naloxone
How does this link in with the
anatomy?
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On the way up…
Aδ - fast - instant reaction
C - slow - throbbing after-pains / chronic pain
Aβ - non-pain but inhibit Aδ and C when stimulated
Rubbing / massage / TENS
Local anaesthetics - block
NSAIDS and ketamine - modulate
Pain to cortex via spino-thalamic tract
How does this link in with the
anatomy?
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In the central processor…
Augment the endorphin system
placebo
opioids
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Psychological
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Self-hypnosis / relaxation
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How does this link in with the
anatomy?
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On the way down…
Noradrenergic pathways - inhibitory
adrenaline in spinals?
Serotonin pathways - facilitate
Block with ondansetron!
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How can we manage pain?
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Multimodal
Multi disciplinary
Analgesic ladder
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WHO
Simple analgesics first
Moderate opioids next
Strong opioids last
Paracetamol
 Is
fantastic!
Paracetamol
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Paracetamol in acute postoperative pain
Clinical bottom line
Paracetamol is an effective analgesic.
A single dose of 1000 mg paracetamol had an NNT
of 3.8 (3.4-4.4) for at least 50% pain relief over 4-6
hours in patients with moderate or severe pain
compared with placebo based on information from
2,759 patients.
Paracetamol is not associated with increased
adverse effects in single dose administration.
NSAIDS
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Non-selective eg. Diclofenac, ibuprofen
Selective eg. Parecoxib, celecoxib
NSAIDS
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Good
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Part of multimodal
analgesia
Bone pain
Opioid sparing
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Bad
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Gastric
Renal
Asthma
Bleeding
 GRAB
Codeine
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Oral codeine in acute postoperative pain
Clinical bottom line:
Codeine 60 mg orally is not an effective
analgesic for postoperative pain.
A 60 mg oral dose of codeine had an NNT of
16.7 (11-48) for at least 50% pain relief over
4 to 6 hours compared with placebo in pain
of moderate to severe intensity.
Tramadol
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Oral tramadol in postoperative pain
Clinical bottom line: Tramadol is an effective analgesic in
postoperative pain. A single 100 mg oral dose of tramadol is
equivalent to 1000 mg paracetamol. A dose of 100 mg had an
NNT of 4.6 (3.6-6.4) for at least 50% pain relief over 4-6 hours
in patients with moderate to severe pain compared with
placebo.
At doses of 50 and 100 mg incidence of adverse effects
(headache, nausea, vomiting, dizziness, somnolence) was
similar to comparator drugs. In dental trials there was increased
incidence of vomiting, nausea, dizziness and somnolence.
Morphine
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The standard against
which others are
measured
Effective
May have side effects
Cheap
Oxycodone
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Synthetic opioid
Developed in 1916 in Germany
Why use oxycodone?
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Subjectively
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Better tolerated
Feel less ‘weird’
Objectively
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Less hallucinations
Lets use it all the time!
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Expensive
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MST 20mg
Oxycontin 10mg
18p
47p
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Better but not perfect
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Still have side effects
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Second line to morphine in
cancer pain
–
Br J Cancer 84(5);587-593
Morphine – Oxycodone relationship
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MST (regular)
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Oxycodone MR (reg)
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Oral morphine solution
(prn)
20mg orally
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Oxycodone IR (prn)
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Oxycontin
Oxynorm
10mg orally
How do regular and PRN work together
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Regular Px?
Having lots of prn?
Is the prn dose
enough?
Increase the regular
dose
Opioid problems
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Respiratory depression
Sedation
Constipation
Nausea and vomiting
Ileus
Urinary retention
Etc, etc, etc…..
Nausea and vomiting
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All of them can cause it
Morphine is especially good at it
Changing analgesic may help
If someone is vomiting give the antiemetics
intravenously!
Itching
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Opioids can cause itching
Especially with neuraxial administration
Difficult to treat
Ondansetron can help
Low dose naloxone can help
Chlorpheniramine less so
Oramorph
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City Campus
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Single nurse
administration
Used lots and lots
Predictable
Oral opioid of choice
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Queens Campus
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2 nurses needed
Used much less
Alternatives used instead
Sevredol, tramadol, DHC
Why?
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I have absolutely no idea!
Abuse and addiction
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Its is a potential
problem
Don’t let that stop you
treating pain
Routes of administration
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Oral
Subcut
Intramuscular
Intravenous
Transdermal
Epidural
Intrathecal
Local Anaesthetics
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Lots of uses
But you may see them cropping up in the
following places:
Epidurals
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Used in surgical
patients
The significance of the
little girl?
Spinals
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Intra and post op analgesia
Can have opiate added to them
Need to watch for respiratory depression
Should have PCA obs even if they don’t have
a PCA
But it still hurts…..
Take a critical look at the drug card
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What have they got?
Regular or PRN?
How much?
How often?
Are they actually taking it?
Is the route appropriate?
Pain Team
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Help on many levels if you have a pain
challenge:
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IVDU
Acute on chronic pain
Pregnancy
Neuropathic pain
Call for advice
How can we do it better?
Identify
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Regular assessment
At rest is not enough
Can they cough?
Can they deep breathe?
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It is easy to be comfortable lying still!
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Respond
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‘An hour of pain is as
long as a day of
pleasure’ Anon
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Be careful not to be
prejudiced
–
Acad Emerg Med 2006;13:140-146
Educate
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Patients
Nurses
Surgeons
Anaesthetists
Kiss-it-Better Hospital
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Don’t forget the
psychological side
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Don’t forget that time and
some physical contact can
make a huge difference
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Acknowledge the problem
and support the patient
And finally….
“Pain makes man think.
Thought makes man wise
Wisdom makes life
endurable.”
(John Patrick 1905-1995)
Pumps and Stuff
PCA - City
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Omnifuse
Clinician code 66643
Just imagine you were
texting OMNIFUSE!
PCA - QMC
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Graseby
No code
Need a key
Can’t do clinician bolus
But Omnifuse should
be coming at some
point this year
Epidurals (non-obstetric)
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Gemstar
Yellow livery
Code 6546
Paravertebrals
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Gemstar
Grey livery
Code 1970
Think of Mr Catton!
Wound infusions
Nerve infusion analgesia
The End