Pain Management in Adult Trauma

Assessment of pain
Non pharmacological management
Pharmacological management: Opioids
Pharmacological management: Non- steroidal anti-inflammatories
Pharmacological management: Local anaesthetics
Common upper limb nerve blocks: Digital block
Common upper limb nerve blocks: Wrist block
Common upper limb nerve blocks: Median nerve
Common upper limb nerve blocks: Ulnar nerve
Common upper limb nerve blocks: Radial nerve

Assessment of Pain

Objectively determine pain by using a pain score or ideally a scale such as the Wong-Baker Faces Pain Rating Scale demonstrated below or a 10-point Likert scale or ruler. This allows re-evaluation of pain and assessment of the efficacy of analgesia.

Patients who have a depressed level of consciousness (from injury or alcohol/drugs) are unreliable in communication of pain – do not withhold analgesia but be aware of the potential for respiratory depression may be increased in these patients.

Non Pharmacological Management

Patient position, especially with respect to fractures, can minimise pain and the need for analgesia. Conversely, analgesia, without managing the cause of the pain is likely to be less effective.

All patients with fractures should have these reduced and splinted wherever possible to decrease pain and decrease the risk of further injury as soon as possible.

Psychological support, such as calming and reassurance also improve the patients perception of pain and will assist in decreasing the amount of pharmacological agents needed for analgesia.

Pharmacological Management

Opioids

Useful for severe pain.

Morphine

• Onset of Action: 3 to 5 minutes
• Duration of Action: 2 – 3 hours
• Administration: IV (IM dose is unreliable in poorly perfused patients)
• Dose: 0.1 to 0.3 mg/kg (this depends largely on the patient’s response)
  • Loading dose: 0.1 to 0.15 mg/kg (use less for elderly and frail) then bolus 0.05 mg/kg every 15 minutes. Titrate to effect.
  • Respiratory rate should >14/min.
• Side Effects: 
  • Hypotension
  • Respiratory Depression
• Reversal Agent: Naloxone (0.4 to 2mg IVI)

There is NO place for pethidine in modern emergency care. 

This is a highly addictive drug with no advantage over other opioids and several disadvantages: seizure potential, drug interactions, and addiction.

Tramadol

• Onset of Action: 5 minutes
• Duration of Action: 4 to 6 hours
• Administration: IV (IM dose is unreliable in poorly perfused patients)
• Dose: 1 to 2mg/kg (this depends largely on the patients response)
• Side Effects: 
  • Hypotension
  • Respiratory Depression
  • Confusion
  • Nausea/Vomiting

Ketamine

• Onset of Action: 1-5 minutes
• Duration of Action: 15-20 minutes
• Administration: IV, IM, oral
• Dose: lower doses have a predominantly analgesic effect, then increasing sedation with higher doses
  • IV 0.5-2 mg/kg
  • IMI/oral 2-5 mg/kg
• Side Effects: 
  • Nystagnus
  • Dysclonic movements
  • Salivation
  • Lacrimation
  • Hallucinations

Non-Steroidal Anti-inflammatories

Useful for moderate pain.

Ibuprofen

• Onset of Action: Oral: 20 to 30 minutes
• Duration of Action: 6 to 8 hours
• Administration: Oral or IM
• Dose: 200 to 400mg every 8 hours
• Side Effects: 
  • Dyspepsia

Diclofenac

• Onset of Action: IM: 5 to 10 minutes Oral: 20 to 30 minutes Rectal: 5 to 10 minutes
• Duration of Action: 6 to 8 hours
• Administration: Orally or IM or Rectal
• Dose: 50 to 75 mg per dose, dose should not exceed 150mg/24h
• Side Effects: 
  • Dyspepsia
  • Renal failure

Paracetamol

• Onset of Action: Oral: 20 to 30 minutes IV: 5 to 10 minutes Rectal 10 to 15 minutes
• Duration of Action: 4 to 6 hours
• Administration: IV, Oral or Rectal
• Dose: 500 to 1000mg every 6 hours
• Side Effects:
  • Hepatic dysfunction

Local Anaesthetics

If the pain of trauma is related to the distribution of one or a few nerves, a nerve block is the most effective method of analgesia and reduces the need for other analgesia.

Newer local anaesthetics are less cardio and neuro toxic. The duration of effect and risk of toxicity is related to the vascularity of the area injected. Dosages should not be exceeded.

Local Anaesthetics with adrenaline or vasoconstrictive properties should not be used in areas with limited collateral blood supply (fingers, nose etc)

All nerve blocks should be treated as moderate risk procedures, and IV access as well as resuscitation equipment should be present before embarking on all but the most minor of regional blocks.

Common Upper Limb Nerve Blocks

Digital Block

• Indications: Surgery on the fingers
• Nerves: Digital nerves
• Local anaesthetic: 2-3 mL per side
  • Never use an adrenaline-containing local anaesthetic
• Technique: 
  • The patient's hand is placed palm down
  • 25G needle is inserted into the finger
  • The needle is advanced through the tissues until just below the skin on the palmar side
  • 1-2mL of local anaesthetic is injected to block the volar branches, as the needle is withdrawn; a further 0.5-1mL is injected to block the dorsal branch.
  • The nerves on the radial aspect of the thumb are best blocked by a subcutaneous wheal of local anaesthetic injected at its base

Wrist Block

• Indications: Surgery on the hand and fingers.
• Nerves: Radial, ulnar, median
• Local anaesthetic: 6 mL per nerve.
  • Never use an epinephrine containing local anaesthetic
• Technique:
  • Each nerve requires a specific technique to properly anaesthetise. Position the patient supine with the hand palmar side up.

Median Nerve

1. Find the Palmaris longus, at 1cm proximal to the distal wrist flexion crease. The Palmaris longus can be found as follows: find the radial artery, roll your fingers toward the ulnar side to feel for the first tendon (this will be the flexor carpi radialis), now roll and feel for the second tendon which will be the Palmaris longus.
2. Move and aim just off the radial side of the Palmaris longus (and medial to the flexor carpi radialis).
3. Insert the needle perpendicularly and advance slowly until a ‘pop’ through the transverse carpal ligament (aka flexor retinaculum).
4. Inject 3-5mL just deeper than the Palmaris longus tendon.

Ulnar Nerve

1.  At the proximal palmar crease, insert the needle on the ulnar aspect of the flexor carpi ulnaris tendon. The flexor carpi ulnaris can be found as follows: find the ulnar artery, and roll your fingers in an ulnar direction over the first tendon which will be the flexor carpi ulnaris.
2. Advance horizontally under the tendon 1.0-1.5cm (paraesthesia should be elicited to confirm proper position close to the nerve within the thick neurovascular bundle).
3. Alternatively, advance the needle toward the ulnar bone deep to the flexor carpi ulnaris and inject as needle is being withdrawn.

Radial Nerve

The radial nerve follows the radial artery to the wrist, but also has superficial branches that supply the dorsal radial aspect.

Primary Injection:

1. Find the radial artery.
2. Aim at the proximal palmar crease, insert lateral (i.e. in a more radial direction) to the artery
3. Inject 2-5mL at the depth of the artery.

Secondary Field Injection:

1. Block branches with a 5-10mL SQ band of anaesthetic from the primary injection site to the dorsal midline (may require 2 injection sites).