Pain assessment in reduced consciousness

At a glance

• Self-report is the reference standard. Many dying patients can still answer yes or no or point; try that before anything else.
• When they can't, use a validated behavioural tool and score at rest and on movement. Each tool detects behaviour that may be pain; none measures pain intensity directly.
• Vital signs are poor indicators. Tachycardia and hypertension come and go with many other causes.
• A raised score means "look for a cause": pain, a full bladder, faecal loading, breathlessness, delirium, fear.
• When in doubt, give an analgesic trial and reassess with the same tool.

Opioid choice and dosing are in Pain in palliative care. Pain in dementia outside the dying phase is covered in Pain management in older patients.

Who can't self-report

Group	Best tool
Advanced dementia (residential care, hospital)	Abbey (Australian) or PAINAD
Dying patient, drowsy or unconscious	PAINAD or Abbey, repeated with care; RDOS for breathlessness
ICU, intubated or sedated	CPOT or BPS
Delirium	Try self-report in lucid periods; otherwise PAINAD
Prolonged disorder of consciousness (after brain injury)	Nociception Coma Scale-Revised, in specialist units

The tools

Tool	Items	Scoring and cut-offs
Abbey Pain Scale	Vocalisation, facial expression, body language, behaviour change, physiological change, physical change	Each 0 to 3, total 0 to 18. 0 to 2 none, 3 to 7 mild, 8 to 13 moderate, 14+ severe
PAINAD	Breathing, negative vocalisation, facial expression, body language, consolability	Each 0 to 2, total 0 to 10. 1 to 3 mild, 4 to 6 moderate, 7 to 10 severe
CPOT	Facial expression, body movements, muscle tension, ventilator compliance (or vocalisation if extubated)	Each 0 to 2, total 0 to 8. Above 2 suggests pain
BPS	Facial expression, upper limb movement, ventilator compliance	Each 1 to 4, total 3 to 12. Above 5 suggests pain
RDOS (dyspnoea, not pain)	Heart rate, respiratory rate, restlessness, accessory muscles, paradoxical breathing, grunting, nasal flaring, fearful look	0 to 16. 3 or more suggests distress needing treatment

• CPOT and BPS have the strongest validation in ICU. In the original CPOT study (Gélinas 2006), scores rose during a painful procedure (turning) and fell afterwards.
• Abbey and PAINAD were built for dementia. They detect distress well but are not specific: delirium, hunger, fear and a full bladder raise them too.

How to assess, step by step

1. Try self-report. Ask a simple closed question, use a squeeze of the hand, or a faces scale.
2. Look for a cause. Known bone metastases, pressure injury, recent surgery, a missed regular opioid, urinary retention, constipation, mouth problems.
3. Observe with one tool, at rest and during turning or care. Record which tool was used.
4. Ask people who know the patient. Family and regular carers recognise changes in that person's behaviour.
5. Analgesic trial. Give the breakthrough SC opioid dose, rescore at 20 to 30 minutes (SC peak), and act on the change.

Worked examples

Example 1: incident pain. A 68-year-old woman with breast cancer and spinal metastases is unresponsive in her last days. PAINAD at rest is 1. When nurses turn her, she grimaces, her breathing becomes laboured and she groans: PAINAD 6.

• Reading: moderate pain on movement only, typical of bone pain.
• Action: give SC morphine (one breakthrough dose) 20 to 30 minutes before turns, reduce the frequency of turning, and check her regular opioid has been converted to a CSCI (see Subcutaneous infusions).

Example 2: not pain. A 90-year-old man with advanced dementia in residential care scores Abbey 12 (moderate) with restlessness and grimacing. His abdomen is distended and dull above the pubis.

• Reading: high score with a palpable bladder.
• Action: bladder scan shows 900 mL. After catheterisation the Abbey score is 2. An opioid would have worsened the retention.

Example 3: expiratory moaning. A dying man moans with every breath. His face is relaxed, his limbs are floppy and the moaning doesn't change when he is turned. PAINAD is 3, all from vocalisation and breathing.

• Reading: probably not pain. Expiratory moaning and Cheyne-Stokes breathing are common near death.
• Action: reposition, give an SC breakthrough dose if uncertain and see whether anything changes, and explain the sound to the family. Don't escalate a regular opioid on this alone.

Example 4: ICU. A ventilated man after a laparotomy, RASS -2. CPOT on turning is 5 (grimacing 2, protection 1, tense or rigid 1, coughing but tolerating the ventilator 1).

• Reading: above the cut-off of 2. Treat pain before deepening sedation (analgesia-first sedation).

Pitfalls in interpretation

• Deep sedation or neuromuscular blockade abolishes the behaviours that tools rely on. A low score doesn't exclude pain.
• Parkinson disease (masked face), facial palsy after stroke and motor neurone disease reduce facial and limb signs.
• Delirium and agitation raise scores without pain. Look for the pattern: pain behaviour that worsens with movement or touch of one area points to pain.
• Opioid toxicity (myoclonus, agitation, allodynia) can look like pain and is made worse by more opioid.
• Stopping regular opioids because the patient is unconscious causes pain and withdrawal. Unconsciousness alone isn't a reason to reduce them; reduce only for signs of toxicity, such as myoclonus, or respiratory depression with pinpoint pupils.
• Using different tools on different shifts. Scores aren't interchangeable.
• Recording a number without acting on it, or without rescoring after treatment.

When it changes management

Finding	Response
Score rises on movement only	Pre-emptive SC breakthrough dose before care
Score raised at rest, falls after an analgesic trial	Increase the regular CSCI opioid
Score raised, no change after opioid	Look for retention, constipation, delirium, breathlessness, fear
Raised score with myoclonus after recent opioid increase or AKI	Opioid toxicity: reduce or rotate
RDOS 3 or more	Treat breathlessness (see Dyspnoea)

TG Palliative Care v5 asks for multidimensional assessment of pain, including emotional, social and spiritual distress. In a patient who can't speak, family can describe what used to comfort them and what that person feared (see Psychological and spiritual needs).