Postoperative self-report of pain in children: interscale agreement, response to analgesic, and preference for a faces scale and a visual analogue scale.

OBJECTIVE: To augment available validation data for the Faces Pain Scale - Revised (FPS-R) and to assess interscale agreement and preference in comparison with the Coloured Analogue Scale (CAS) in pediatric acute pain.
METHOD: The present prospective, multicentre study included 131 inpatients five to 15 years of age (mean age 8.8 years; 56% male) seen in postoperative recovery. They provided CAS and FPS-R pain scores before and after administration of analgesic medication. Nurses and physicians used the same tools as observational scales. Children and health care providers indicated which scale they preferred.
RESULTS: FPS-R scores for the intensity of postoperative pain correlated highly with the corresponding CAS scores in all age groups (0.66 <or= r <or= 0.88). There were no significant mean differences in any age group between the scales. Scores on the two scales differed by 210 or less in 81% to 91% of children, depending on age. Both scales demonstrated expected changes in postoperative pain following administration of an analgesic. Scores at the upper end point were given by approximately 20% of children five to six years of age on both scales, compared with 2% to 9% in the older age groups. Health care providers' observational ratings were significantly lower than self-ratings. The FPS-R was preferred over the CAS by most children in all age groups and both sexes. Global satisfaction of the health care providers was similar for both tools. DISCUSSION: These results support the use of the FPS-R for most children five years of age or older in the postoperative period. Further research is needed to identify young children, particularly those younger than seven years of age, who have difficulty with self-report tools, and to establish methods for training them in the reliable use of these measures.