Visual Analogue Scale in Acute Pain measurement: Its Usefulness as a Pain Measurement Tool in an Emergency Setting

ABSTRACT

PURPOSE: The Visual Analogue Scale (VAS), as a pain measurement tool, has been shown to be a reliable measurement for chronic pain. However, the reliability and the validity of the VAS have not been demonstrated in an acute setting where pain fluctuations might be greater than they would be for chronic pain. This study assessed the usefulness of the VAS in an emergency setting. METHODS: Patients 16 years of age or older who presented with acute pain resulting from trauma or non-traumatic diseases were enrolled in this prospective, observational study. A 100-mm non-hatched, horizontal visual analogue scale was used to measure the pain severity. VAS measurements were obtained 1 minute apart at admission, 30 minutes after admission, and 1 hour after treatment. Intraclass correlation coefficients (ICCs) with 95% confidence intervals (95% CIs) and a Bland-Altman analysis were used to assess the reliability and the validity of the VAS measurements. RESULTS: The ICCs for paired VAS scores at admission, 30 minutes after admission, and 1 hour after treatment were 0.988 (95% CI=0.98 to 0.99), 0.968 (95% CI=0.95 to 0.98), and 0.989 (95% CI=0.98 to 0.99), respectively. The Bland-Altman analysis showed that 95% of the paired measurements at admission, 30 minutes after admission, and 1 hour after treatment were within 7 mm. CONCLUSION: The VAS appears to be a highly reproducible instrument for measurement of acute pain in the emergency department. This study suggests that the VAS is sufficiently reliable to be used to assess acute pain.