Pain measurement during labor: comparing the visual analog scale with dermatome assessment

The purpose of this article is to examine the agreement between two measures of pain in laboring women who receive epidural analgesia for relief to support validity and reliability of the Visual Analog Scale (VAS) in this population.

There are several different approaches to measuring pain in laboring women. However, the psychometric properties of pain relief measures in this population are not well established. This investigation examines agreement (i.e., concordance) between the visual analog scale for pain sensation and sensation measured by dermatome level assessment.

Fifty pregnant women in labor who underwent epidural placement recorded their sensation of pain on the VAS simultaneously with the certified nurse anesthetist recording sensation by using a standard dermatome chart after administration of epidural analgesia.

There was moderate, significant correlation between the two measures. However, agreement between the two measures did not meet preset standards with Bland-Altman analysis, suggesting that one measure cannot be substituted for the other. Overall, the average dermatome levels alone underestimated pain in laboring women as recorded by the VAS, although both under-and overestimation of pain relief occurred during the series of observations.