Assessing Pain: Do the Scales Measure Up?
Blood pressure is not an objective measure of pain.
Pain is a subjective experience, and reporting of pain may vary from patient to patient.
There are many methods to evaluate pain in a patient, including verbal, numeric and visual assessments.
The verbal rating scale employs adjectives from the patient to describe their pain, with descriptions like “no pain” to “extremely intense pain.” The value of this scale is its simplicity, as this scale is quite easy to use, and compliance is higher than other methods. However, the verbal rating scale is limited in that these adjectives can differ from patient-to-patient, and that it can be difficult to accurately diagnose pain if a patient has a high pain tolerance.
Patients can also describe their pain using numbers, such as from zero to 10, known as the numeric rating scale. This scale has well-documented validity, and is also easily administered, but the main weakness of this scale is that it does not have ratio qualities.
The visual analog scale, shows pain along a horizontal and vertical orientation. It is similar to the numeric rating scale, and is recommended to measure pain intensity, but it is limited in that it is often difficult to administer to patients with perceptual motor problems.
The Mcgill Pain Questionnaire is a three-dimensional, sensory, motivational, measured way to assess pain, with 20 sets of verbal descriptors, from lowest to highest.
Of course another way to assess pain is through observation and vital sign assessment. However, it is important to remember the limitations of these forms as well, as heart rate and blood pressure have not proven objective methods of assessing pain.