Overview of Pain Scales
Pain rating scales, also called pain scales, are used by physicians and other health care providers to evaluate pain and measure pain levels. Pain measurements help determine the severity, type, and duration of the pain, and are used to make an accurate diagnosis, determine a treatment plan, and evaluate the effectiveness of treatment.
Types of pain rating scales include verbal scales, numerical scales, and visual analogue scales. Verbal rating scales consist of a series of words commonly used to describe pain (e.g., no pain, mild pain, moderate pain, severe pain). The patient reads the words and chooses the one that best describes the pain he or she is experiencing. A score (e.g., from 0–3) that is assigned to each word is then used to measure pain levels.
Numerical rating scales usually consist of a series of numbers ranging from, for example, 0 to 10. The ends of the scale are labeled to indicate "no pain" and the "worst pain possible." The patient chooses the number that best corresponds to the level of pain he or she is experiencing.
Visual analogue scales commonly consist of a vertical or horizontal line, 10 cm in length, with end points labeled "no pain" and the "worst pain," or similar words. The patient is asked to place a mark on the line that corresponds to the intensity of the pain he or she is experiencing.
Some types of visual analogue scales attempt to measure the overall annoyance of the pain, as well as its severity, by using words such as, "not too bad," "very unpleasant," and "most distressing imaginable."
Wong-Baker FACES Pain Rating Scale
From Hockenberry MJ, Wilson D, Winkelstein ML: Wong's Essentials of Pediatric Nursing, ed. 7, St. Louis, 2005, p. 1259. Used with permission. Copyright, Mosby.
These pain scales have advantages and disadvantages. They are simple, minimally intrusive tests that are effective and easy to administer and score, in most cases. However, verbal, numerical, and visual analogue scales cannot be used in all patients. They may be ineffective in patients who have cognitive or motor problems, in patients who are unresponsive (e.g., due to injury), and in young children and elderly patients.
One major disadvantage of pain rating scales is that pain often cannot be accurately described and measured on the basis of severity alone. To describe pain only in terms of its intensity is like describing what we can see only in terms of light or dark, without regard for colors, patterns, or textures. A number of studies have been performed to specify qualities of pain further.
Since 1975, the McGill Pain Questionnaire (developed by Ronald Melzack) has been a widely-used pain assessment tool. This questionnaire, which is completed by the patient, takes about 5 minutes to fill out. It consists of 20 groups of words (subclasses) that can be used to describe pain and a pain rating index.
The patient chooses words to describe the pain he or she is experiencing. The 20 subclasses of words are broken down into four major groups to describe the sensory qualities of the pain (e.g., throbbing, sharp, stabbing), the affects of the pain (e.g., sickening, blinding, grueling), the overall experience of the pain (e.g., annoying, intense, unbearable), and miscellaneous characteristics of the pain (e.g., radiating, piercing, nagging).
Each word chosen is assigned a rank value and these values are used to determine the pain rating index (PRI). The PRI ranges from 0 (no pain) to 5 (excruciating pain).
A modified version of this questionnaire (Short-form McGill Pain Questionnaire [SF-MPQ]) was developed in 1987. This form may be used in some cases, for example, when time is limited.