The Definition and Assessment of Pain


Helping people in pain was the original necessity that birthed the professions midwifery, surgery, pharmacy, medicine, and nursing—in that order, in fact. Yet pain today is still the proverbial elephant in front of 5 blind people. Despite exponential advances in understanding the biology of pain, new analgesics, and improvements in analgesic delivery methods, we continue to be constrained, in fact hobbled, by 2 problems: first, the definition of pain does not fully address suffering, and second, the tools we use to measure pain are often inadequate.

Pain can cause great suffering, yet some people in great pain do not suffer. Women giving birth can experience pain without suffering; conversely, even a very dense epidural will not alleviate the terror and fear some women experience during labor. The relationship between pain and suffering is a fundamental paradox with an infinite number of personal variations. Pain must be defined in terms that acknowledge the nature of suffering. Therapeutic interactions can be partially successful when pain is addressed but real healing, helping, and caring only occur when suffering is attended to as well.

A widely accepted definition of pain currently used in the health care field was put forth by the International Association for the Study of Pain (IASP) in 1994. The definition states that “Pain is an unpleasant sensory and emotional experience associated with actual or potential tissue damage or described in terms of such damage.” The definition emphasizes a broader meaning with inclusion of the following 2 additional points:

“Pain is always subjective. Each individual learns the application of the word through experiences related to injury early in life.”

“The inability to communicate verbally does not negate the possibility that an individual is experiencing pain and is in need of appropriate pain-relieving treatment.”1

This definition is vastly improved over the “pain-is-suffering-for-sins” explanation that was put forth by Christian philosophers in the Middle Ages—one that influenced health care practices well into the 20th century. However, it does not differentiate between 2 distinct and important aspects of pain: perception and interpretation. There is a subtle but profound difference between these 2 different mental functions.

Perception is influenced by myriad factors, including age, gender, culture, and individual history. Suffering is the result of how pain is interpreted. An individual experiencing chronic pain may perceive it to be debilitating, but might interpret the situation as a challenge to work for a specific quality of life. Another person may perceive chronic pain as debilitating and interpret the situation as one that is insolvable, a conclusion that will most certainly lead to suffering. Qualitative research methodologies and large population-based surveys are laudably being used more frequently to help characterize women's perceptions of pain.2 Research investigating factors that affect the interpretation of pain is needed.

Furthermore, suffering can be both the product of pain and simultaneously a source of it. Physiologic pain stimuli are detected by nociceptive nerve fibers that transmit the information to the dorsal horn of the spinal cord, and at the same time, they release a neuropeptide called substance P. Substance P sensitizes the nerve fiber to detect pain stimuli more rapidly,3 a positive feedback mechanism called “hyperalgesia” that increases sensitivity to pain. Suffering is the emotional equivalent of substance P. It magnifies the experience of pain. It needs to be better characterized. It is a big part of the “elephant” that we have yet to describe adequately.

Assessing pain is a challenge in clinical practice, where, on a day-to-day basis, the definition has been truncated to, “Pain is whatever the patient says it is.” This simplification has inadvertently spawned the use of pain assessment tools that are quick, reliable, valid, and easy to perform, but inadequate for most patients.4 The most commonly used assessment tool is a visual analogue scale (VAS) that rates pain on a 1 to 10 scale. At best, a VAS can help providers titrate specific pain medications to mitigate the intensity of pain sensation expressed by a person capable of communicating verbally. At worst, these scales provide the health care provider with false reassurance that an adequate assessment has been made.

Self-report pain assessment tools such as the VAS presume that the individual understands and can respond to the questions being asked. There are 2 problems with this assumption: First, many groups of individuals do not have the cognitive or communication skills to complete a self-assessment measure. For example, elderly persons with dementia may not be able to understand or to communicate clearly, despite having the ability to hear and respond verbally. Likewise, newborns experience pain, but they, too, need assessment of their pain in ways that do not include self-report, beyond the obvious cry. These are just 2 examples of populations poorly served via reliance on VAS scores. And these examples do not even address additional relevant factors, such as communication across cultures that render suspect any widespread reliance on self-assessment pain scores.

Secondly, the quantified VAS score gives health care providers implicit permission to ignore additional data, such as the hunching of shoulders, an observable tension between partners, or the sheen of tears on a family member's face—behavioral clues that can be critical indicators of pain.5 A woman in labor may be able to rate pain on a scale of 1 to 10, but she might not tell me that she also is panicked about the possibility of a large perineal tear and future disability. If I don't look at her, detect her tension, sit with her, and learn from her, I won't truly comprehend what she is experiencing. I may be able to treat her perception and ranking of contraction pain, but I will not respond to her suffering because the VAS score does not assess suffering.

Behavioral responses to acute pain are universal indicators of pain. In fact, acute intense pain does not allow time for the development of individualized responses. In many acute-care settings, these universal physical signs may be more reliable than reported VAS scores. On the other hand, behavioral expressions of anxiety or suffering will not be eliminated by epidural anesthesia. Let's not forget to look for these cues of suffering, let's not forget to address them when present in individuals under our care, and let's not forget to teach students to do the same.

Following the assessment of pain and suffering comes treatment. Given the multifaceted etiology of pain, it is not surprising that treatments that are both really safe and truly effective have eluded us since opium was discovered. Neither should it be surprising that nonpharmaceutical interventions work. What is surprising is how little we know about something that, like birth and death, is an inevitable experience in each of our lives.

This issue of the Journal of Midwifery & Women's Health includes information to help us move a step toward further understanding the experience of pain and its treatment. Traditional and modern concepts of pain are discussed. Pain as experienced during such life experiences as labor, menstruation, and menopause are addressed. Concepts ranging from philosophical descriptors of pain to algorithms for clinically addressing certain painful conditions are included. Just as important for the reader to understand is that this topic, like the manifestation of pain itself, is vast. Many experiences of women's pain, such as vulvodynia, sexual pain, and fibromyalgia, are not specifically addressed here. Some will be included in upcoming articles in JMWH. Others have been addressed and updated in recent issues of JMWH.6

The need to understand an individual's pain rests squarely in the heart of every patient interaction in midwifery practice. No matter what the topic, practitioners must recognize that pain is not easily simplified to such concepts as “whatever the patient says it is,” a VAS score, or “the fifth vital sign.” Pain for the individual embodies a physiologic sensation, perception, interpretation, and suffering. Understanding pain requires listening, observing, and empathizing. None of this is simple. But then, as any woman in labor can tell you, neither is pain.