Acute Pain - Health Education East Midlands VLE (Moodle)

Principles of Acute Pain

Management

29.9.10

Rik Kapila

What this talk isn’t….

 A pharmacology lecture

 A physiology lecture

 Comprehensive

What this talk is ( I hope!)….

An overview

Relevant

Enlightening

Interesting

An opportunity

What is pain?

“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…

“whatever the experiencing person says it is, existing whenever he says it does."

Margo McCaffrey 1968

Epictetus (55-135 A.D)

‘It is not death or pain that is to be dreaded but the fear of pain or death’

Lance Armstrong (1971- present)

‘pain is temporary – quitting lasts forever’

Saint Augustine of Hippo (354-430)

‘the greatest evil is physical pain’

Does pain matter?

Cardiovascular

Tachycardia

Hypertension

Increased myocardial oxygen consumption

Myocardial ischaemia

Respiratory

Decreased lung volume

Atelectasis

Decreased cough

Sputum retention

Infection

Hypoxia

Gastrointestinal

Decreased gastric motility

Decreased bowel motility

Ileus

Genitourinary

 Urinary retention

Metabolic

Increased catabolic hormones

Cortisol

Glucagon

Growth hormone

Reduced anabolic hormones

– Insulin

– Testosterone

Psychological

Anxiety

Fear

Sleep disturbance

Depression

Distressing for patient, family and staff

Chronic Pain after Surgery

 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

1975 endorphin enkephalin

 Dynorphin

 synthesised in pituitary

Receptors in the peri-aqueductal gray matter

Endogenous morphine

Responsible for “hedonistic tone”

Increase descending inhibition in spinal cord

 Increased release in:

– happiness touch / massage sex exercise hypnosis / relaxation

– placebo effect -anticipation of the above

Endogenous morphine

 Increased release in:

– 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?

On the way up…

A δ - fast - instant reaction

C - slow - throbbing after-pains / chronic pain

A β - 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?

In the central processor…

 Augment the endorphin system

 placebo

 opioids

 Psychological

 Self-hypnosis / relaxation

How does this link in with the anatomy?

On the way down…

 Noradrenergic pathways - inhibitory

 adrenaline in spinals ?

 Serotonin pathways facilitate

 Block with ondansetron !

How can we manage pain?

 Multimodal

 Multi disciplinary

Analgesic ladder

WHO

Simple analgesics first

Moderate opioids next

Strong opioids last

Paracetamol

Is fantastic!

Paracetamol

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

 Non-selective eg. Diclofenac, ibuprofen

 Selective eg. Parecoxib, celecoxib

NSAIDS

 Good

– Part of multimodal analgesia

Bone pain

Opioid sparing

 Bad

Gastric

Renal

Asthma

Bleeding

 GRAB

Codeine

 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

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

The standard against which others are measured

Effective

May have side effects

Cheap

Oxycodone

 Synthetic opioid

 Developed in 1916 in Germany

Why use oxycodone?

 Subjectively

Better tolerated

Feel less ‘weird’

 Objectively

– Less hallucinations

Lets use it all the time!

 Expensive

MST 20mg

Oxycontin 10mg

 Better but not perfect

18p

47p

 Still have side effects

 Second line to morphine in cancer pain

– Br J Cancer 84(5);587-593

Morphine – Oxycodone relationship

 MST (regular)  Oxycodone MR (reg)

– Oxycontin

 Oral morphine solution

(prn)

 Oxycodone IR (prn)

– Oxynorm

 20mg orally

 10mg orally

How do regular and PRN work together

Regular Px?

Having lots of prn?

Is the prn dose enough?

Increase the regular dose

Opioid problems

 Respiratory depression

 Sedation

 Constipation

 Nausea and vomiting

 Ileus

Urinary retention

Etc, etc, etc…..

Nausea and vomiting

 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

 Opioids can cause itching

 Especially with neuraxial administration

 Difficult to treat

 Ondansetron can help

 Low dose naloxone can help

 Chlorpheniramine less so

Oramorph

 City Campus

– Single nurse administration

Used lots and lots

Predictable

Oral opioid of choice

 Queens Campus

2 nurses needed

Used much less

Alternatives used instead

Sevredol, tramadol, DHC

Why?

 I have absolutely no idea!

Abuse and addiction

Its is a potential problem

Don’t let that stop you treating pain

Routes of administration

Oral

Subcut

Intramuscular

Intravenous

Transdermal

Epidural

Intrathecal

Local Anaesthetics

 Lots of uses

 But you may see them cropping up in the following places:

Epidurals

Used in surgical patients

The significance of the little girl?

Spinals

 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

 What have they got?

 Regular or PRN?

 How much?

 How often?

 Are they actually taking it?

 Is the route appropriate?

Pain Team

 Help on many levels if you have a pain challenge:

– IVDU

– Acute on chronic pain

– Pregnancy

– Neuropathic pain

 Call for advice

How can we do it better?

Identify

Regular assessment

At rest is not enough

Can they cough?

Can they deep breathe?

 It is easy to be comfortable lying still!

Respond

‘An hour of pain is as long as a day of pleasure’

Anon

 Be careful not to be prejudiced

– Acad Emerg Med 2006;13:140-146

Educate

Patients

Nurses

Surgeons

Anaesthetists

Kiss-it-Better Hospital

Don’t forget the psychological side

Don’t forget that time and some physical contact can make a huge difference

 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

Omnifuse

Clinician code 66643

Just imagine you were texting OMNIFUSE!

PCA - QMC

Graseby

No code

Need a key

Can’t do clinician bolus

 But Omnifuse should be coming at some point this year

Epidurals (non-obstetric)

Gemstar

Yellow livery

Code 6546

Paravertebrals

Gemstar

Grey livery

Code 1970

Think of Mr Catton!

Wound infusions

Nerve infusion analgesia

The End