gas notes - pain management

Question 1

What typically triggers acute pain?

Answer 1

Nocioception due to tissue damage

An example is stepping on a Lego brick.

Question 2

How long does chronic pain persist after the initial insult?

Answer 2

More than three months

Question 3

What is hyperalgesia?

Answer 3

Pain out of proportion to a stimulus

Question 4

What does allodynia refer to?

Answer 4

Painful interpretation of non-painful stimuli

Question 5

Define neuropathic pain.

Answer 5

Pain originating from conducting nerve damage

Question 6

What is phantom limb pain?

Answer 6

Pain after amputation of a limb

Question 7

Why is chronic pain more difficult to treat than acute pain?

Answer 7

It typically originates from harder-to-target levels above transduction, including within the brain itself.

Question 8

What is paracetamol?

Answer 8

An effective and relatively-harmless analgesic that should feature in (almost) every pain management plan

Paracetamol is widely used due to its safety profile and efficacy in managing pain.

Question 9

What do NSAIDs do?

Answer 9

Block the formation of inflammatory prostaglandins by inhibiting cyclo-oxygenase enzymes (COX)

NSAIDs can lead to issues such as renal impairment, GIT ulceration, ischaemic heart disease, and bronchospasm.

Question 10

What is the role of opioids in pain management?

Answer 10

Heavy lifting in acute pain but limited role in chronic pain management

Opioids are more effective for short-term pain relief rather than long-term management.

Question 11

What is tramadol?

Answer 11

A hybrid opioid and SSRI that increases descending inhibition

Tramadol provides good analgesia for most patients but should be avoided in older patients due to the risk of delirium.

Question 12

What is tapentadol?

Answer 12

A metabolite of tramadol that causes less delirium and is more expensive

Tapentadol is often used when tramadol is not suitable.

Question 13

What is buprenorphine?

Answer 13

A ‘partial agonist’ at μ opioid receptors that has less respiratory depression and equal analgesia

Buprenorphine can be safely co-prescribed with other opioids at normal doses.

Question 14

What is unique about oxycodone?

Answer 14

Has a pretty fast onset and is excellent for severe acute pain

Oxycodone has immense potential for abuse, requiring careful monitoring.

Question 15

What are the characteristics of morphine?

Answer 15

The original opiate, not commonly used today, very nauseating, and accumulates toxic metabolites in renal failure

An antiemetic is often co-prescribed with morphine to manage its nausea.

Question 16

What is fentanyl?

Answer 16

Very fast and short-lived with perfect safety in renal failure

Fentanyl is often used in acute settings due to its rapid action.

Question 17

Is there a role for codeine in modern pain management?

Answer 17

No, there is no role for codeine in modern pain management

Codeine has largely been replaced by more effective analgesics.

Question 18

What are the primary adverse effects of opioids?

Answer 18

Nausea, sedation, and dose-dependent respiratory depression

These effects highlight the importance of careful dosing and monitoring in opioid therapy.

Question 19

What formulations do most opioids come in?

Answer 19

Slow-release and immediate-release formulations

The choice of formulation can depend on patient needs and local policies.
try to use the same drug for both

Question 20

list some adjuvants

Answer 20

Ketamine
Pregabalin (and gabapentin)
Clonidine
Tricyclic antidepressants
SNRIs

Question 21

What are the three common local anaesthetics in Australia?

Answer 21

Lignocaine, Bupivacaine, Ropivacaine

Lignocaine is primarily used in day-to-day practice, while Bupivacaine and Ropivacaine are used in more specific contexts.

Question 22

What concentrations are available for Lignocaine?

Answer 22

1% or 2%

Lignocaine is often pre-mixed with adrenaline.

Question 23

Which local anaesthetic is popular for spinal blocks?

Answer 23

Bupivacaine

Bupivacaine is available in concentrations of 0.25% or 0.5% and is sometimes pre-mixed with adrenaline.

Question 24

What concentrations are available for Ropivacaine?

Answer 24

0.2%, 0.75%, and 1%

Ropivacaine is popular for regional blocks and is sometimes pre-mixed with adrenaline.

Question 25

What is Local Anaesthetic Systemic Toxicity (LAST) characterized by?

Answer 25

Arrhythmia, seizure, and coma in severe cases ## Footnote LAST is almost always caused by accidental intravenous injection.

Question 26

True or False: Ropivacaine is used primarily for spinal blocks.

Answer 26

False ## Footnote Ropivacaine is popular for regional blocks, while Bupivacaine is used for spinal blocks.

Question 27

What should you always do before injecting local anaesthetic to avoid LAST?

Answer 27

Draw back ## Footnote Always draw back before injection to check for accidental intravenous injection.

Question 28

What is the primary aim of regional anaesthesia?

Answer 28

To bathe a single nerve (or plexus) in local anaesthetic to prevent nocioceptive transmission ## Footnote This technique is used to block pain signals from specific areas of the body.

Question 29

What guidance method do most anaesthetists use for regional anaesthesia?

Answer 29

Ultrasound guidance ## Footnote Ultrasound allows for better visualization of nerves and improves the accuracy of anaesthetic delivery.

Question 30

What is a major benefit of regional anaesthesia?

Answer 30

It is an excellent opioid-sparing technique ## Footnote This means it can reduce the need for opioids during and after surgery.

Question 31

What is a common side effect of local anaesthetic in regional anaesthesia?

Answer 31

Motor blockade ## Footnote Local anaesthetic not only blocks pain but can also affect muscle movement.

Question 32

What is intravenous regional anaesthesia?

Answer 32

An old-school technique where a limb is isolated from circulation by tourniquet and flooded with intravenous local anaesthetic ## Footnote This method was historically used for procedures on the limbs.

Question 33

What is Bier’s block?

Answer 33

A famous example of intravenous regional anaesthesia ## Footnote Named after Heinrich Bier, this technique involves a tourniquet and local anaesthetic administration.

Question 34

What risk is associated with intravenous regional anaesthesia?

Answer 34

High risk of toxicity ## Footnote Due to the concentration of local anaesthetic in a confined area, there is a significant risk of systemic absorption leading to toxicity.

Question 35

Why is intravenous regional anaesthesia becoming redundant?

Answer 35

Due to the wide availability of ultrasonography ## Footnote Ultrasonography provides safer and more effective alternatives for nerve blocks.

Question 36

What is neuraxial anaesthesia?

Answer 36

A type of local anaesthesia applied to the spine that numbs the entire lower half of the body with a small dose of anaesthetic ## Footnote It is risky, invasive, time-consuming, and difficult.

Question 37

When are neuraxial techniques relevant?

Answer 37

They are relevant for surgery below the umbilicus ## Footnote Particularly useful for avoiding general anaesthesia in high-risk patients.

Question 38

What are the benefits of neuraxial anaesthesia in high-risk patients?

Answer 38

Avoids the need for large doses of opioids and hypnotics ## Footnote This can reduce the risk of complications associated with general anaesthesia.

Question 39

At which vertebral level does the spinal cord typically terminate in adults?

Answer 39

L2 ## Footnote Below L2, there is a collection of nerve roots and cerebrospinal fluid (CSF) known as the lumbar cistern.

Question 40

Where should the needle be aimed when performing a neuraxial block?

Answer 40

At the L3/4 interspace or lower ## Footnote This helps to avoid damaging the spinal cord.

Question 41

What is a spinal block?

Answer 41

A single shot of local anaesthetic injected into the lumbar cistern ## Footnote Sometimes mixed with other agents and cannot be 'topped up' once they wear off.

Question 42

List the structures the needle passes through to reach the subarachnoid space.

Answer 42

* Skin * Subcutaneous fat * Supraspinous ligament * Interspinous ligament * Ligamentum flavum * Epidural space * Dura mater * Arachnoid mater * Lumbar cistern ## Footnote This pathway is crucial for the administration of spinal anaesthesia.

Question 43

What is the density characteristic of local anaesthetic compared to cerebrospinal fluid?

Answer 43

Local anaesthetic is slightly less dense than cerebrospinal fluid (hypobaric) ## Footnote It can be made 'heavy' (hyperbaric) by mixing with dextrose.

Question 44

What effect does a heavy mixture of local anaesthetic have when the patient lies on their side?

Answer 44

Produces a unilateral block ## Footnote This is due to the heavy mixture sinking.

Question 45

What is an epidural block?

Answer 45

A technique where a flexible catheter is threaded into the epidural space ## Footnote Local anaesthetic is periodically injected to anaesthetise the nerve roots.

Question 46

What are epidurals best suited for?

Answer 46

Long-lasting pain like labour and delivery.

Question 47

True or False: Neuraxial blocks are generally considered unsafe and poorly tolerated.

Answer 47

False ## Footnote Neuraxial blocks are generally safe and well-tolerated.

Question 48

What are the main risks associated with neuraxial blocks?

Answer 48

* Failure (especially epidurals) * Headache * Bleeding * Infection * Neurological injury * High block ## Footnote These risks should be communicated to patients before the procedure.

Question 49

What are some contraindications for neuraxial blocks?

Answer 49

* Patient refusal * Impaired coagulation * Raised ICP * Uncooperative patient * Underlying neurological or spinal disease * Fixed cardiac output * Shock

Question 50

What is a 'high block' in the context of local anaesthetic administration?

Answer 50

A phenomenon where local anaesthetic migrates above T4, causing profound bradycardia, hypotension, and diaphragmatic paralysis.

Question 51

What is the life-threatening condition that can occur if local anaesthetic reaches the cranium?

Answer 51

'Total spinal' anaesthetic.