The question of how best to measure pain in animals
was posed at VetsSouth in a fascinating presentation
by Jacky Reid from NewMetrica and Glasgow University Vet School.
Acute pain is an important consequence of surgery,
trauma or medical illness, and failure to manage it well can
lead to consequences such as delayed recovery and poor
healing, as well as unnecessary and protracted suffering.
Gone are the days when it was considered acceptable for
an animal recovering from surgery to be in pain so that
they would not move around too much. In human medicine
it is considered that pain assessment should be the fifth
vital sign measured, after pulse, respiration, temperature
and blood pressure.
Animals are all individuals, just like humans, so how can
we make sure that each one is given the right amount of
analgesia at the right time? And how can we measure what
degree of pain any animal is suffering when they cannot tell
us what they are feeling verbally?
Jacky explained that we can use behavioural observations to measure the response to pain, and non-verbal
communication can be used as a form of self-reporting. All
that is needed is an observer (veterinary surgeon or nurse
in the case of an animal that is recovering from surgery or
hospitalised following trauma or illness) and a composite
scale which enables us to measure that animal’s response
to pain.
The Glasgow Composite Measure Pain Scales
(CMPS-SF for dogs
and CMPS-Feline for
cats) have been tested
for validity, reliability,
responsiveness and
sensitivity in the target
species. They are easy
to use and interpret and
have an intervention
level set, which provides
guidance as to whether an animal requires
analgesia. Spontaneous behaviours, for example vocalisation and attention to a wound, and evoked behaviours
(such as response to touch) are scored, as well as posture,
demeanour, mobility in dogs and facial expression in cats.
The incorporation of the latter in a previous version of the
cat scale greatly improved its sensitivity.
In practice, for post-operative purposes, the scale is used
once the animal has fully recovered from general anaesthe-
sia, then approximately every three to four hours thereafter
depending on the individual. If the intervention level is
reached, analgesic should be administered and the pain
score repeated in one hour to check that the analgesic has
reduced the pain level.
Jacky has been highly involved in the development of this
tool and her talk highlighted the importance of considering
behaviour as a measurable entity, enabling us to manage
pain more effectively and humanely.
