Assessment of clinically significant changes in acute pain in children.

OBJECTIVE: To quantify, using two pain assessment scales, the amount of change in pain severity required to achieve a clinically significant improvement in pain in children presenting to a pediatric emergency department (ED) with pain.
METHODS: Prospective, descriptive study involving all children presenting to a pediatric ED between 5 and 16 years of age inclusive with acute pain. Children were excluded if they 1) were intoxicated or had altered sensorium, 2) were clinically unstable, 3) were non-English-speaking, or 4) were developmentally delayed. Written informed consent was obtained. Children were asked to mark their current pain severity on the standardized Color Analogue Scale (CAS) and Faces Pain Scale (FPS). After each pain control intervention the child was asked to repeat these measurements and to describe whether his or her pain was "much less," "a little less," "about the same," "a little worse," or "much worse" compared with before. This process was repeated until the child was discharged from the ED or had a score of zero. The main outcome measure was the smallest change on the CAS or FPS necessary to cause the child to describe his or her pain as a "little less." This was defined as the clinically significant change in pain. The "ideal" change in pain was defined as the amount of change necessary for the child to describe the pain as "much less" or at which point the child thought he or she no longer required any medicine to help the pain go away.
RESULTS: One hundred twenty-one children were enrolled with a mean age of 9.8 years (SD +/- 3.15). Males accounted for 56%. Pain was traumatic in 65% and nontraumatic in 35%. A total of 153 pain comparisons were made using the CAS and 154 using the FPS. Only three children complained that their pain got worse (two a little worse and one much worse). Pain was described as "the same" in 20. Of the 60 pain comparisons judged to be a "little less," the CAS score changed by a median of 2.0 cm [interquartile ratio (IQR) 1-3], and the FPS by 1.0 face (IQR 1-2). In the 71 children who judged their pain to be "much less," the CAS decreased by a median of 4.0 cm (IQR 2-5) and the FPS by 2.0 faces (IQR 2-3).
CONCLUSIONS: The assessment and treatment of pain in children are an important component of pediatric practice, especially in the ED. This study provides health care professionals and clinical investigators the information necessary to assess whether their method of pain control in children is clinically relevant.