Assessing Pain of the Pediatric Patient in the Emergency Setting
A pain scale measures pain intensity and is based on self-report, observational (behavioral), or physiological data. Self-report is usually considered primary and should be obtained if possible. Pain scales are also available for neonates, infants, children, adolescents, adults, seniors, and persons whose com-munication is impaired.
Quantifying and standardizing pain intensity in children in an acute setting is a difficult task. Currently, there exists a myriad of self-report scales that aim to facilitate this process. Although these scales are ubiquitous in modern healthcare, there is continuous scrutiny in regards to their reliability. This review aims to demonstrate the important var-iables that can alter a child’s perception of pain, and therefore his or her report of pain intensity.
Assessing Reliability of Pain Scales
The reliability of self-reported pain intensity in children can be assessed by careful consideration of the following factors:
- The advantages and shortcomings of the type of pain scale being used
- The demographics of the patient
- The qualities of the health care provider conducting the assessment
- The etiology of the pain that the child is suffering from
- The physical and social environment the child is in at the time of self-report.
These five variables must be taken into account to be able to reliably utilize a sub-jective pain report as an efficacious tool for accurate means of assessing a child’s pain severity in the emergency department.
First, it is important to consider the attributes of the particular pain scale chosen. Although many self-report pain scales exist, they can generally be categorized into pictorial scales and numerical analogue scales. The quintessential pictorial scale is the Faces Pain Scale-Revised1 (see Figure 1). The Faces Pain Scale-Revised consists of six faces, beginning with a neutral face and advancing to a crying face, as shown below. The neutral face is assigned a pain rating of 0/10, and each face increases by an increment of 2/10. Each face is explained to the child as increasing levels of “hurt,” with the first face being designated “no hurt” and the last face designated as “the worst hurt you have ever felt.” The child is then instructed to point to the face that corresponds to his/her level of perceived pain.
The Faces Pain Scale-Revised is very easy to implement in the emergency setting, as it does not require much explanation to the patient and/or his/her family. Also, since the scale lacks many words, it is quite convenient for use with a foreign-speaking patient. Although it is seemingly obvious that each face seems to be in more pain than the last, few studies have analyzed whether or not these faces are accurate and precise representations of pain. Rather, these faces may be more representative of anxiety, which is described as more general feelings of apprehension and fear.2 Situational, as well as demographic, factors may have a large impact on a child’s level of anxiety and may pose a threat to this test’s overall validity and reliability—these factors will be discussed later. Also, with only six faces, simplified scales such as the Faces Pain Scale may not provide enough sensitivity to be useful for monitoring smaller or more gradual changes in pain during long-term management of the patient.
Another option for subjective pain assessment is the use of numerical analogue scales (see Figure 2). Numerical analogue scales are also popular because of their ease of use. These types of scales also may overcome the simplicity of pictorial scales. Most scales are ranked from 0-10, on either a horizontal or vertical axis as seen in Figure 3. The patient is requested to mark on a linear scale a number that corresponds to his/her perceived pain level.
Numerical scales provide specific challenges, especially in the pediatric population. Children have a propensity to have response biases, which are systemic biases that may cause self-reported answers to not reflect reality because of the respondent’s misperception. A commonly seen and well-researched example of a type of response bias is anchoring. Anchoring is a cognitive bias that describes the common human tendency to rely too heavily, or “anchor,” on one trait or piece of information when making decisions. In children, this manifests as choosing either the lowest or the highest number on a pain scale, with disregard for the numbers in between. Previous studies have suggested that anchor biases can occur in up to 1 out of 5 children who use self-report pain scales.3 Such biases also correlate with the age and cognitive ability of the patient, which will be discussed later. Although numerical analogue scales attempt to provide a more precise measurement of pain, the presence of such biases suggest that they may not be a reliable indicator of pain for the pediatric population.
The Oucher Scale4 utilizes both a visual analogue and a numerical rating scale side-by-side in a vertical fashion as depicted in Figure 3. The child is asked to point to the picture that correlates to his/her level of “hurt” and this is then translated into a number score. This allows the scale to be utilized by most pediatric patients over the age of three. Also, the scale comes in many cultural versions (Caucasian, African American, Hispanic, Asian). Although this scale covers a wide variety of patients, several other cultures are not covered. For patients whose cultures are not represented, this scale can be confusing and alter their perception of pain severity. Also, the relevance between the facial expressions and designated numeric values have not yet been validated. This can be potentially misleading to the child as well as the provider interpreting the response. The simultaneous utilization of both formats (photographic, numeric) diminishes clarity on whether the patient used only one format or was influenced by the other in making a decision of his or her pain.
Recent research on African-American and Hispanic versions of the Oucher scale have approached the problem of simultaneous presentation by eliminating the lines connecting the photographs and the numbers and placing the photographs on one side of the poster and the numeric format on the other.5 Overall, each pain scale has something different to offer the clinician in assessing a child’s pain but each scale’s shortcomings must also be taken into account when choosing which one to employ.
Lastly, it is important to note that a pain score, regardless of which scale is used, is more useful for comparing changes over time within an individual, rather than comparing the score itself between individuals.6 It is impossible to tell if child A’s pain of an 8 is more severe than child B’s pain of a 7. However, if child A’s pain decreases to a 2, and child B’s to a 6, that would be considered a measurable and significant change specific to each child.