1.4 Pain Management

Question 1

What are the 2 major types of pain?

Answer 1

1. Somatogenic
   
   • Nociceptive (acute)
   • Neuropathic (chronic)
2. Psychogenic (when physical examination and investigations fails to detect cause of pain)

Question 2

Describe the management options for different levels of pain.

Answer 2

1. Urgent, severe pain requiring resuscitation
   
   • Perform CABCDE
   • Titrate morphine/fentanyl +/- ketamine
   • Consider IM midazolam
2. Subacute severe pain, e.g. renal colic
   
   • May start IV to get pain under control, then transition to PO mixture of regular pain relief, narcotics and PRNs after controlled pain
3. Mild/moderate pain
   
   • Regular Panadol and Nurofen
   • Breathrough oxycodone

Question 3

What are the tenets of morphine use?

What are some common side effects?

Answer 3

• 1st line for acute pain.
• Usually IV, easily titrated and reversible with naloxone.
• Use monitoring!

Common side effects:

• Hypotension
• Narcosis
• Hypersensitivity (as can cause histamine release) - if this happens, consider fentanyl
• Nausea is not common side effect, usually due to pain

Question 4

Describe the dosing of morphine.

Answer 4

Dosing

1. Adult:
   
   • 1st dose 5mg
   • Then given at 3-5 min intervals, titrated boluses of 2.5-5mg until pain controlled.
2. Child:
   
   • 1st dose 0.1mg/kg (don’t exceed 5mg)
   • Then given at 3-5 min intervals, titrated boluses of 0.05-0.1mg/kg (don’t exceed 2.5-5mg) until pain controlled.
3. Elderly:
   
   • 1st dose 1-2.5mg
   • Then at 5-10 min intervals, titrated boluses of 1-2.5mg until pain controlled

Question 5

What are the tenets of fentanyl use?

What are some common side effects?

Answer 5

• IV or IN, useful for paediatric populations.
• Rapid onset, short duration.
• Easily reversible with naloxone.
• Use monitoring

Common Side Effects

• Can cause truncal rigidity, but this is very rare in ED settings, usually occurs in anaesthetic settings.
• Be aware of high concentration vials

Question 6

Describe the IV dosing of fentanyl.

Answer 6

5mg of morphine is equivalent to 50mcg fentanyl.

IV Dosing

1. Adult:
   
   • 1st dose is 50mcg
   • Titrate in 25mcg boluses at 3-5min intervals until analgesia attained
2. Child:
   
   • 1st dose 1-2mcg/kg (max 50mcg)
   • Titrate in 0.5-1mcg/kg boluses at 3-5min until analgesia attained
3. Elderly:
   
   • 1st dose 25mcg
   • Titrate in 15-20mcg doses at 5-10min intervals until analgesia attained

Question 7

Describe the IN dosing of fentanyl.

Answer 7

First 0.1mLs is lost to ‘dead space’ in the nebuliser.

Dosing

1. Aged 1-5 years: 30mcgs
2. Aged 6-15 years: 75mcgs

Townsville Hospital protocol is 1.5mcg/kg

Question 8

What are the tenets of ketamine use?

Answer 8

• Dissociative anaesthesia in high doses
• Highly effective analgesic in low doses
• Safe, large therapeutic window

Question 9

Describe the IV dosing of ketamine.

Answer 9

Dosing

1. Adults:
   
   • 20-30mg boluses
   • Caution with previous narcotics
   • Slow push, not fast bolus
2. Paediatrics:
   
   • 3-5mg/kg
   • Manage as sedated patient with monitoring and expertise (at TUH, this occurs in resusciation area)

Question 10

What options are there for PO non-narcotic medications?

Answer 10

1. Paracetamol
   
   • PO, IV, PR
2. NSAIDs
   
   • PO (ibuprofen, ketorolac)
   • PR (indometacin)
   • IM (ketorolac)

Question 11

What options are there for PO narcotics?

Answer 11

Always warn the patient of not operating heavy machinery or driving.

1. Oxycodone, 5-10mg 6 hourly
   
   • Oxycontin
   • MS contin
2. Codeine
   
   • Many Sfx, including GI upset, also unpredictable due to interactions and different metabolisers
   • Rapid metabolisers who are breastfeeding - do not use
3. Tramadol
   
   • Do not prescribe in ED, due to interactions ++

Question 12

What options are there for inhaled analgesics?

Answer 12

1. Nitrous oxide
   
   • Can come premixed 50-50, or be used 70-30 with mixer
   • Useful for procedures and for paediatric populations
2. Methoxyflurane
   
   • ‘Green whistle’

Question 13

List 3 commonly used non-medication strategies to manage pain.

Answer 13

1. Communication (reassurance, confidence, family member present)
2. Splinting
3. Dressing
4. Distraction

Question 14

Describe how to perform a digital nerve block.

Answer 14

The sensory nerve of the finger lies on the lateral aspect of the finger just palmar to the midline.

Digital Nerve Block

Draw up 5mL of 1% lignocaine (no adrenaline) and infiltrate with 25G needle (orange). Use alco-wipe, then enter the finger at 2 o’clock about 1 cm, then infiltrate medially, dorsally and laterally about 1.5mLs each part.

Webspace Block

Alternatively, can enter at webspace, 5mm proximal to the distal part of the webspace. Infiltrate the webspace on either side of the injured finger.

Question 15

Describe the nerves often used for facial blocks and the areas of the face they cover.

Answer 15

See image.

Question 16

Describe the process of a femoral nerve block.

Answer 16

Video: https://vimeo.com/108739595

Used for fractured neck of femur.