Pain is one of the most common reasons for paramedics to be called, and something we are well equipped to deal with. Understanding and following your guideline is part of the battle, however understanding the different causes of pain and the nuance of the different medications is what makes a big difference to patients.

Assessment of Pain

Assessment of pain is a key part of paramedic assessment. Often described as a vital sign itself, pain score is usually assessed using a verbal numerical scale (“pain score”). Pain should be assessed on a scale from zero (no pain) to 10 (the worst pain imaginable). However you may have experienced that people do not always comprehend or apply this scale correctly. It’s not uncommon to hear the response “my pain is 12/10” or “my pain is an 8, but my pain tolerance is really high”.

So, what is the paramedic to do with this? Well that’s a bit controversial. Of course we need to take a patient’s word for how severe their pain is. It’s also important to remember that there are cultural and medical differences in how pain may be outwardly expressed (patients with chronic pain may appear calm, but be in significant pain). It’s vital that paramedics consider our own biases/expectations (how do I imagine a patient with severe pain will act?) and factor that in to our assessments.

What about the non-verbal or non-English speaking patient? In these people a non-verbal pain score (NVPS) may be useful – check it out at MDCalcs.

[https://www.mdcalc.com/nonverbal-pain-scale-nvps-nonverbal-patients]

Paramedics should also use their experience and judgment to assess severity of pain, and when in doubt, treat what the patient says they are experiencing. Be sure to re-assess pain score and vital signs before administering more analgesia, and always titrate to symptoms and side effects.

Analgesia Options

Paracetamol

• Oral analgesia which works in the central nervous system
• Comes as tablets and elixir (paediatrics) in AV. IV infusion is also available (air ambulance only)
• Indicated for mild/moderate pain, severe headache or for more severe pain in conjunction with other medications
• Few contraindications

Morphine

• Often referenced as the ‘gold standard’, morphine is an opioid analgesia which acts as an agonist at mu, kappa and delta opioid receptors
• Named for the Greek god of sleep Morpheus, which indicates its side effect of drowsiness
• Given IV / IM / subcut
• Indicated for moderate/severe pain
• Contraindications are hypersensitivity, renal impairment and late second stage labour
• Due to morphine’s influence on multiple opioid receptors, it has a bigger side effect profile than the synthetic Fentanyl

Fentanyl

• A synthetic opioid which primarily acts on mu opioid receptors
• Given IV / IN / IM / subcut
• Indicated for moderate/severe pain
• Has less of a side effect profile than morphine, typically causing less nausea, hypotension and respiratory depression

Methoxyflurane

• A volatile anaesthetic agent which has analgesic properties at low doses
• It is inhaled using a Penthrox inhaler (green stick)
• Indicated for moderate procedural pain (such as splinting or joint relocation)
• Few contraindications – hypersensitivity, malignant hyperthermia and renal impairment
• Downside is that analgesia fades as soon as the inhaler is removed

Ketamine

• An NMDA receptor antagonist with partial mu opioid receptor antagonism, which results in sedation, dissociation and analgesia
• Can be given IV / IM / IN
• Used as an adjunct to opiates in severe pain, or by intensive care paramedics for severe procedural pain
• Can cause emergence phenomena and distress

Approach to treating pain

Non-pharmacological

• Reassurance
• Distraction
• Position
• Splinting
• Heat/cold
• Anything else that works for the patient

Mild Pain (1-3/10)

• Paracetamol should be given (if not already)
• If further analgesia required OR immediate relief from pain needed, consider IN Fentanyl

Moderate Pain (4-6/10)

• Paracetamol (generally best to give this at scene where you have access to tap water AND gives it time to kick in)
• IV Opioid
  • Morphine is the first choice
  • Fentanyl should be used if specifically indicated (nausea, hypotension, morphine contraindicated, short duration of action desirable)
• If unable to obtain IV access or the paramedic suspects IV analgesia not necessary, IN Fentanyl can be given
  • If IN Fentanyl contraindicated, give IN Ketamine
• If pain still not controlled, or there is acute procedural pain, add on Methoxyflurane
• [note that Methoxyflurane should NOT typically be used in isolation!]

Severe Pain (8-10/10)

• IV Opioid + IN Ketamine
  • Morphine is the preferred first line, but the ‘specific indications’ for Fentanyl still apply here
  • IN Ketamine is indicated in all severe pain patients, but use your common sense. Ketamine is indicated in severe traumatic or surgical pain
  • Given IN Ketamine has a 20 min repeat, I suggest getting it onboard whilst establishing IV access
• If you can’t get IV access, use IN Ketamine + IN Fentanyl
• If no IV and patient not suitable for IN (such as facial trauma), you can give IM Morphine/Fentanyl
• If appropriate, add on oral Paracetamol
• If pain still not controlled, request MICA or consult Clinician for IV Ketamine

Severe Headache

Has its own guideline, as opiates often aren’t helpful in severe headache

• Oral Paracetamol + IM Prochlorperazine
• If after 15/60 pain is still >7/10 AND transport more than 15/60 to hospital
  • Give IV/IN Fentanyl as per standard pain relief CPG, aiming for pain score < 7/10
• Note that opioids typically prolong recovery from headaches and are not really helpful. Ketamine may raise ICP and therefore should not be used

Bottom Line

Adequate relief from pain is a fundamental human right, however it is up to paramedics to properly assess and manage symptoms. Outlined here is a standard approach to treating pain which will suit MOST patients, however special circumstances exist for palliative patients, patients with chronic pain and severe headache. Consider the pharmacology and the goals of pain treatment, rather than following a one-size fits all approach.