Acceptability of visual analogue scales in the clinical setting: a comparison with verbal rating scales in postoperative pain

Abstract

Pain is the clinical symptom most difficult to evaluate. Although clinical trials methodology have permitted assessment of pain objectively through rating scales, these strategies have not been used in clinical setting. The present study was undertaken to determine if visual analogue scales could be useful in the measurement of postoperative pain in usual medical practice. The study comprised 212 patients with abdominal, orthopedic or gynecological surgical procedures within the previous 24 h. Patients evaluated their pain using a verbal rating scale (VRS) of five points or a visual analogue scale (VAS) of 10 cm. The investigators also evaluated patient pain through a VAS. The results obtained showed that a high correlation between VRS and VAS could be established in all patients (p less than 0.001). The VAS of patients and researchers were also found to be highly correlated (p less than 0.001). When values of each group were compared by pain intensity a total agreement of VAS scores at low pain level could be established, but differences were found at high pain intensity levels, suggesting that physicians scored lower than patients when pain was severe to unbearable. It is concluded that VAS could be a reliable method to assess pain in clinical setting.