6 – Pain Measurement Flashcards
Physiological indicators of pain
- Related to activation of SNS
- Increased HR, RR, BP, T, pupil dilation
- Increased biomarkers: beta-endorphin
*unreliable and not specific to pain (influenced by other factors: anxiety, stress, fear)
Pain indicators
- Behaviour
- Posture
- Facial expression
Practical subject approach: observing patient
- Without interaction
o Orientation in cage, posture, activity level, facial expression, attitude - While interacting
- Response to palpation of painful site
Interacting with patient
- Call by name
- Stroke along back from head to tail
- Appropriate response?
- Tense?
- Anxious?
- Indifferent?
Response to palpation of painful area
- No reaction to touch, but vocalizes/tenses with pressure
- Looking at area
- Withdraws
- Defensive by protecting area
- Withdraws fast, vocalizes, bites
- Freezing, gets rigid
Challenges of pain assessment in animals
- Use of proxy (ex. DVM or owner: not the animal itself)
- Variant in pain response: age, species, individual
- Environmental or situational stressors (may mask pain)
- Different types of pain (ex. acute vs. chronic)
Fearful vs. painful animals
- Fearful will probably still look at you
Developing a pain assessment tool
- User friendly
- Score linked to an INTERVENTION level
- Valid
- Reliable
- Responsive
Use of pain assessment tool?
- Increases objectivity and accuracy
- Improve consistency of pain recognition
- Assess response to treatment
- Ensure pain is PRIORITIZED
- Quantify pain
*NEED AN OUTCOME MEASURE
Preventive (pre-emptive) scoring system
- Score assigned according to level of pain that they are BELIEVED to experience
o none, mild, moderate, severe - not useful to treat individual patient
- simple to use
- allows preventative analgesic planning
Anticipated levels of pain: mild
- early, resolving simple conditions
Anticipated levels of pain: mild to moderate
- castration
- minor dental procedures
Anticipated levels of pain: moderate
- urethral obstruction
- C-section
Anticipated levels of pain: moderate to severe
- Osteoarthritis
- Peritonitis
- Ureteral, urethral obstruction
Anticipated levels of pain: severe to excruciating
- Multiple factors
- Limp amputation
- Necrotizing pancreatitis
Subjective or unidimensional scales: examples
- Simple descriptive scale (SDS)
- Numerical rating scale (NRS)
- Visual analog scale (VAS)
- Dynamic interactive visual analog scale (DIVAS)
*don’t recommend using them
Simple descriptive scale
- Most basic, easy to use
- Not validated
- 4-6 descriptors
- Scales are non-linear
- Descriptive words are open to different interpretations
- Extremely subjective
- Lack sensitivity to detect small changes in pain
Numerical rating scale
- Similar to SDS
- Implies equal differences or weighting between each category
- ‘discontinuous scale’
Visual analog scale
Visual analog scale
* Horizontal line representing pain experience
* 0: no pain, 10: worst pain possible
* Extensively used in humans (completed by patient)
* Vetmed: significant interobserver variability
Dynamic and interactive visual analog scale (DIVA)
- Improvement of VAS
- Includes dynamic and interactive assessment of patients
o Observe from distance, interact, palpation
Multidimensional scales
*recommend using
* Categorized numerical rating scales
* Multi-dimension composite pain scales
Categorized numerical rating scales
- Observe and interact
- Different categories where certain behaviours are chosen and assigned a value
- Sum of category scores=pain score
- Species and situation specific
UMPS (University of Melbourne Pain Scale)
- Clinical use
- Multiple descriptors in 6 categories
- Total score of 27
- Not validated, labour intensive
- Requires baseline data
Colorado state university canine acute pain scale
- Teaching tool
- Dogs and cats after trauma or surgery
- 3 categories are assessed and assigned a score 0-4
- Observation and hands on
- Practical, user friendly
- NOT validated
Multi-dimension composite pain scales
- Glasgow composite measures pain scale
- UNESP: MCPS
Glasgow composite measure pain scale (CMPS)
- First validated canine acute pain scale
- 7 behavioural categories with 47 descriptors
- Too time consuming
- Useful research tool, not feasible in clinical environment
CMPS: short form
- Highly practical, clear repeatable
- Acute pain
- Behavioural assessment
- Reduced interobserver validity
- Validated
- Intervention score
- *6 behavioural categories
UNESP- Botucatus Multidimensional Composite Pain Scale (MCPS)
- Validated for cats undergoing OHE
- 4 broad categories
o Psychomotor changes
o Protection of wound area
o Physiologic variable
o Vocal expression of pain - Score 0-30
Cow pain score
- 7 behaviours evaluated
- Intervention score=5/14
Facial expression scoring system: grimace scale
- Identify and assess severity of pain
- Rabbits, horses, sheep, pigs
- Easy to use
- Often incorporated in multidimensional pain measures or standalone
Facial action units
- Orbital tightening
- Ear position
- Cheek bulge
- Nose bulge
- Whisker position
Horse grimace score
- Composite, simple descriptive scale
- 6 facial parameters with well-defined categories
- Good reliability and validity
- Other emotional states don’t change score significantly
- Easy and give to use
- Not validated against independent data set
Chronic pain assessment
- Use owner as proxy
- Ex. Helsinki chronic pain index (HCPI)
- Ex. canine brief pain index
- Liverpool osteoarthritis in dogs
- Feline musculoskeletal pain index
- Client specific outcome measures
Clinical measurement instruments for chronic pain: evaluate behaviours in normal setting
- Going up and down stairs
- Eating
- Grooming
- Ability to jump in car
- Difficulty in rising
- Inappropriate urination or defecation
*useful to assess effect of treatment
Canine Brief Pain Inventor
- Chronic pain: osteoarthritis, bone cancer
- Record owners assessment
- Assess pain severity and how pain interferes with daily life/function
Feline musculoskeletal pain index: measures impact of osteoarthritis on domains of:
- Pain
- Mobility
- Activity
- Affective effects
Client specific outcome measures -felines (CSOMf)
- Choose 3 behaviours that the cat doesn’t do well anymore or has stopped doing
- Easier as there is only 3 behaviours for them to have to assess
Gait analysis: force plate, pressure mat walkways
- Objective methodology to evaluate limb motion
- Research and referral facilities
- Not practical in everyday
- Difficult to interpret in presence of multiple arthritic joints
- Helpful in detection of changes in lameness but not stiffness
Accelerometers: activity monitors
- Objective, non-invasive, portable
- Able to evaluate active movement at home
