pain assessment in ed an evidence-based update

PAIN ASSESSMENT IN THE EMERGENCY DEPARTMENT

AN EVIDENCE-BASED UPDATE

Anne-Maree KellyProfessor and DirectorJoseph Epstein Centre for Emergency Medicine Research @Western Health , Melbourne, Australia

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‘Re p ro duc e d with p e rm is s io n o f Pro fe s s o r Anne -Ma re e Ke lly , Jo s e p h Ep s te in Ce ntre fo r Em e rg e nc y Me d ic ine Re s e a rch @ We s te rn He a lth, Me lbo urne , Aus tra lia ’

@kellyam_jec

Conflicts of interest

None to declare

CAVEAT: The focus of this talk is on pain scenarios that commonly present to ED. Procedural analgesia and sedation have not been specifically addressed.

Objectives

After this presentation, participants will:

Have an understanding of the methods available to assess pain in the emergency department, including their strengths and weaknesses

Be aware of the challenges of pain assessment

The truth about pain assessment

Pain is a subjective experience….objective measurement is impossible

Pain experience is a complex phenomenon Physical and psychological dimensions In ED, usually measuring intensity/ severity Describing pain only in terms of intensity is like describing

music only in terms of loudness

Pain assessment in context

In ED there are three main variables that impact pain assessment Patient characteristics

E.g: Age, cognition, conscious state Pain characteristics

E.g: Acute vs. chronic The purpose for which we are measuring pain

E.g: pain management vs. research

`

Purpose

Pain management Indication of intensity/ severity Detection of change Identification of pain control/ need for additional pain relief

Research Precision regarding intensity/ severity and detection and

quantification of change

Methods for pain assessment

Vital signs Behavioural features Clinician assessment Patient self-report

Numerical methods Categorical methods

Desirable features of a pain scale

Valid, reliable Culturally, developmentally

appropriate Easily understood by patients

of varying education Well accepted by patients

and clinicians

Quickly and easily explained to patients

Low burden on clinician Low cost Readily available Translated/ adaptable into

various languages

Ada p te d fro m Va n Ba e y e r, 2 0 0 6

Poor performing methods

Vital sign measurements (eg pulse, blood pressure) have been shown repeatedly not to be reliable in pain assessment of individual patients.

Clinicians assessment of pain agrees very poorly with patient self report.

Both of these methods should be avoided if other methods can be used.

Easier said than done

Evidence that clinicians continue to demonstrate paternalism regarding pain assessment

Despite the evidence Despite the wide introduction of pain scoring

Measuring acute pain

Self report Preferred if possible to use

Observation scales Usually used with young children, the cognitively

impaired or those unable to communicate

Self report of pain

Verbal categorical scales Numerical rating scales Visual analogue scales Image scales e.g. FACES scales

Verbal categorical scales

Example format:

‘No ne ’‘Mild ’‘Mo de ra te ’‘Se ve re ’

Strengths: Simple Valid and reproducible

Weaknesses: Poor sensitivity to change in pain Low precision Research suggests temporal variation

in correlation with numerical scales Difficult for patients with cognitive

issues

Verbal categorical scales

Low precision and sensitivity to change in pain intensity makes these unsuitable for research use

Low sensitivity to change in pain intensity and difficulty of use by some patient groups limits utility as pain management tool

May be useful as a screening tool

Numerical rating scales

Example format: Usually 0-10 Can be administered verbally or visually Can be vertical or horizontal

Variants of NRS

Coloured scales Combine numerical with

colourimetric queues Not been shown to be

superior to NRS

Numerical rating scales

Simple, practical Valid and reliable Sensitive to short term

changes in pain Well accepted by patients Flexible administration, e.g.

by phone

Can be variation in description of the anchor numbers

? Lower precision than VAS Debate about whether truly

continuous for analysis ?Less accepted as a

research tool

Strengths Weaknesses

Visual analogue scale

Example format: Patient asked to mark the line Usually an un-hatched 100mm line Pain score is the number of mm from ‘0’ end of the line

Variants of VAS

Coloured scales Often coloured on one

side and numerical on the other

Reliable and well accepted in children and cognitively impaired

Visual analogue scales

Valid and reliable Sensitive to changes in pain Well validated as a research

tool

Reliant on vision and written response

Harder to comprehend by elderly and cognitively impaired

Patients find harder to use than NRS

Strengths Weaknesses

NRS or VAS?

Research suggests psychometric properties are very similar

NRS better accepted by patients

VAS better accepted by researchers

Recent change in opinion

Because of: Ease of use Fit with clinical pain management Patient preference Higher completion rate

NRS increasingly accepted as both clinical and research tool

Image scales

Patient presented with a set of images and asked to choose the one that best represents their pain

The image chosen corresponds with a number for analysis

Variety of similar tools

Image scales

Valid and reliable Simple to use Correlate with numerical

methods e.g. VAS Able to be used by children

and some patients with cognitive impairment

Limited experience with disease-related pain most validated on procedural

pain Questions regarding

interpretation and analysis Continuous vs. categorical

Some scales show bias at upper or lower end

Strengths Weaknesses

A bit more about analysis

Demonstrated correlation with VAS

VAS bands are not discrete

VAS bands are not the same size

Tendency to analyze as if continuous-? justified

The balance of evidence

In conscious, cognitively sound adolescents and adults: The numerical rating scale is best accepted and

validated for pain management and has growing acceptance as a research tool

VAS is best validated as a research tool but is harder to use and less accepted by patients

My opinion

Numerical rating scale is best all-round pain assessment tool

Children

Most children aged 5 or over can provide self report of pain intensity - if an age-appropriate tool is used

By 9 or 10 years, numerical rating scales or VAS are well accepted and reliable

Pain scales by age

Two major reviews Substantially in

agreement Apply to both pain

management and research

Acknowledge limited evidence for some tools

Age group Preferred scale

3-6 (Preschool)

Pieces of Hurt

4-12 Faces pain Scale-Revised

5-17 Coloured analogue scale

9+ Numerical rating scale (or VAS)

Observation scales

FLACC Faces, legs, activity,

cry, consolability Validated for post-

operative pain in children 2 months to 7 years

Alder Hay Triage Pain Score Cry/ voice, facial

expression, movement, colour, posture

Reliability and validity in early studies

Observational scales: The evidence

Solid evidence that observational pain scales under-estimate pain in children aged 3 and older

Not a surprising result

Should not be used in preference to an age-appropriate self report tool

Cognitively impaired adults

Includes patients with dementia

Self report of pain is possible by many patients in this group

Lack of evidence regarding performance of various tools for different levels of cognitive impairment

The evidence

There is some evidence that with increasing cognitive impairment, VAS and numerical rating scales are harder to use

Faces pain scale-revised Well accepted Low failure rate, even in moderate-severe impairment

Observation scales

Most not developed for use with acute pain

FLACC and PAINAD scores have been used

Limited data on validity and reliability

PAINAD score

Interesting new area of research

Pain assessment in the unconscious / intubated patient A number of tools in development Include behavioural assessments +/-

physiological parameters Varying psychometric properties Clinical utility to be established

Examples

Critical care pain observation tool (B) Behavioural pain scale (B) Non verbal adult pain assessment scale (B) Pain assessment and intervention notation

algorithm (B + P)

Some areas for further research

Reliability, validity and clinical utility of self report tools across different levels of cognitive impairment and cultural and education groups

Pain assessment in children under 6 years Pain assessment in sedated/ unconscious

patients

Take home messages

When feasible, patient self-report of pain using an appropriate tool is the most valid and reliable approach across all age and cognitive groups

Observational scales are a poor alternative

Measuring pain is not enough

All of the science of pain measurement means nothing if it does not result in action to relieve pain

Pain measurement may be the fifth ‘vital sign’ but unless a response to address it is triggered we are wasting our time

Questions?

Questions?Questions?

@kellyam_jec