Opioid Prescribing and Monitoring - (Second Edition)
Primary Care Models for Pain Management

Assessment and Monitoring of Pain: Current Tools

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The Centers for Disease Control and Prevention (CDC) guidelines for prescribing opioids for chronic pain have brought renewed attention to the field of pain management. Health care professionals who treat pain require objective measures that incorporate both emotional and sensory aspects of a patient’s pain experience. This is far from easy, however.

Pain is inherently subjective and could be considered an emotional response to a personal experience. In fact, emotional suffering is an important and perhaps underappreciated aspect of persistent pain.1 At the same time, pain is ubiquitous, familiar, and among the most common reasons for accessing the United States health care system.2

Acute pain tends to be more straightforward to quantify than chronic pain. Monitoring the time to reaction from various levels of noxious stimulation in an experimental setting can provide an objective measure for both humans and animals. Chronic pain, however, frequently lacks an apparent noxious stimulus. Measurements of such pain are typically based on a patient’s self-report or on clinical observations of the patient’s behaviors. Both may lead to unreliable results.3

The key to understanding pain evaluation tools is recognizing that acute and chronic pain are fundamentally different and not necessarily related. The proposed process of “algopathy,” for example, describes a continuum of pain from “an acute, adaptive, expected pain to a chronic, maladaptive, centralized pain.” This creates a multitude of changes in the neural-system perception of pain, in pain processing by the brain, and in the way patients perceive pain in an emotional context.4 In essence, algopathy outlines a transformation of acute pain into chronic pain and explains a mixture of both conditions.

Current Pain Metrics

Regular pain assessments are important components of chronic pain therapy. The ideal pain assessment tool would produce a numeric score or other objective metric, be easy to administer, be readily understood by patients, and yield reproducible results with good specificity and sensitivity. Many clinically tested and validated pain scales exist (for a full listing, go to https://www.practicalpainmanagement.com/resource-centers/opioid-prescribing-monitoring/list-clinically-tested-validated-pain-scales).5-29

The visual analog scale (VAS) is among the most frequently used pain scales in the US.30 With the VAS, clinicians ask patients to describe their pain by pointing to the most representative area along a line labeled “no pain” at its left end and “the worst pain imaginable” at its right end. For the Wong-Baker FACES scale, the best-known pediatric pain assessment tool, clinicians show children 6 faces—from a smiling happy face to a vigorously crying face—and ask which face best represents their current pain level.21

Pain manifests itself in numerous ways (eg, functional limitations, emotional symptoms, physical sensations, and behavioral changes), and clinicians should be careful to choose the pain assessment tool that most closely corresponds to a patient’s symptoms and conditions. This variation in functionality can cause confusion because pain scales are not interchangeable—a 10 on 1 scale may not be equivalent to the same score on another. What’s more, pain scales may measure not only pain intensity but also changes over time, functional limitations, emotional aspects, and behavior.

To establish these measures, pain scales rely on either patient self-reporting
or assessment by a health care professional (or a parent, family member, or caregiver in some cases). Self-reports may or may not be consistent over time but have been validated in many studies of pain assessments.

The language of pain is crucial to its reliable evaluation. Longer, more comprehensive descriptions of pain may be easier for a patient to grasp and categorize than pain descriptors, such as “moderate pain” or “pain that is getting worse.” It also may be clinically meaningful to evaluate pain not in terms of its intensity but rather in terms of how much and in what ways it interferes with function. For instance, being able to sit comfortably through a movie may be more relevant to a chronic pain patient than dropping 1 point on a numeric rating scale. Pain scales may further neglect emotional components of pain and symptoms of mental distress, such as depression, anxiety, and stress.

Despite laudable efforts to develop metrics that accurately and consistently measure pain levels over time, none of the many tools available achieve this task perfectly. For that reason, the Indiana Polyclinic Combined Pain Scale (IPCPS) was developed 15 years ago to offer the breadth required by certain chronic pain patients, the simplicity necessitated by a hectic clinical practice, and the versatility needed to accommodate a wide range of patients.

New Assessment Scales

The IPCPS consists of a combined pain scale, combined function scale, combined depression scale, and combined anxiety scale (see Tables 1-4, page 36-39). The new assessment tools, which were developed by the authors, attempt to account for the full spectrum of the pain experience and may provide a more accurate way of assessing and documenting chronic pain.

How IPCPS Measures Pain Intensity

The IPCPS rates pain intensity on the familiar 11-point scale, with 0 meaning “no pain” and 10 indicating “the worst possible pain imaginable.” Clear definitions of various pain states are more prominent than the scale’s numbers, however. With these added descriptions, along with examples, pain patients may be better able to contextualize and evaluate their pain intensity experiences.

Each patient completes the initial report without assistance from the health care team. During the appointment, the clinician then reviews the completed form with the patient (and any accompanying caregivers). Everyone is free to ask questions. Through discussion and clarification, the patient can gain an improved understanding of the pain intensity score and may revise the original report to eliminate unnecessary errors or inappropriately high or low reported scores. Because pain intensity can fluctuate in chronic pain patients, it is important for clinicians to frequently and consistently evaluate pain with the IPCPS.

How IPCPS Incorporates Functional Impairment

Chronic pain interferes with function and can, in turn, affect patients’ well-being, independence, and ability to pursue the normal activities of daily living. One standard measurement of function is the Functional Independence Measure (FIM), an 18-item questionnaire that describes 13 motor functions (including eating, grooming, and bathing) and 5 cognitive functions (including expression, social interaction, and memory). Patients rate each function individually on a scale of 0 to 7.31 The higher the score, the better able the patient is to independently perform that task. The FIM scale requires that clinicians be trained in its use and observe the patients as they perform specific tasks.

Last updated on: September 13, 2017
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