Comparison of a verbal numeric rating scale with the visual analogue scale for the measurement of acute pain. [Article

Department of Emergency Medicine, St George Hospital, Gray St, Kogarah, NSW 2217, Australia.
Emergency Medicine Australasia 10/2003; 15(5-6):441-6. DOI: 10.1046/j.1442-2026.2003.00499.x
Source: PubMed


To test the agreement between the visual analogue scale (VAS) and a verbal numeric rating scale (VNRS) in measuring acute pain, and measure the minimum clinically significant change in VNRS.
Patients scored their pain by the VAS and the VNRS, then re-scored their pain every 30 min for up to 2 h. Patients also recorded whether their pain had improved or worsened. Agreement between scores was evaluated, and where patients scored their pain as 'a bit worse' or 'a bit better' the mean change in VNRS was calculated.
A total of 309 paired observations were obtained from 79 patients. The VAS and VNRS were highly correlated (r = 0.95, 95% CI 0.94-0.96). The VNRS was significantly higher than the VAS for the paired observations, with 95% of the differences between VAS and VNRS lying between -2.3 and 1.3 cm. The minimum clinically significant difference in VNRS was 1.4 cm (95% CI 1.2-1.6).
The VNRS performs as well as the VAS in assessing changes in pain. However, although the VAS and VNRS are well correlated, patients systematically score their pain higher on the VNRS, with an unacceptably wide distribution of the differences.

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    • "One of the medications which its anxiolytic effects have been studied in dental procedures and on patients with cancer is nitrous oxide (N2O) (3-5). Administration of 50% N2O causes analgesia and reduces fear of pain and anxiety in patients, but has mild and self-limited side effects (6-8). Considering the adverse effects of anxiety on patients and also the side effects of usual anxiolytic medications, efforts to achieve an effective modality to treat anxiety in pregnant women who undergo caesarean section are important. "
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    Anesthesiology and Pain Medicine 05/2014; 4(2):e16662. DOI:10.5812/aapm.16662
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    • "As this was a non-inferiority study, the sample size was determined based on how much higher the pain score in the intervention group would have to be to show that VL + LA should not be used without analgesics (equivalence margin). Studies using the NRS in combination with physiological measures of pain have shown that the minimum clinically relevant difference in pain is around 1.3 [18,19]. The standard deviation (SD) of pain scores during gynecological procedures tends to fall within the range of 3–3.5 using an 11-point scale [20,21]. "
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    BMC Women's Health 02/2014; 14(1):21. DOI:10.1186/1472-6874-14-21 · 1.50 Impact Factor
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    • "A 1 cm difference on a 10 cm VAS represents 10% of the scale, and to detect mean differences of this magnitude between the two arms of the trial with 90% power (at the 5% significance level) will require sample sizes of 203, 144 and 86 per group respectively in the 3 scenarios. A 1 cm difference is similar to the difference in pain intensity at 60 minutes found by Fairlie (0.9), is not larger than the 1.4 cm identified by Holdgate et al [13] as being the minimum change in pain that can be subjectively identified by patients with acute pain, and represents a standardised effect size of 0.38. We will set sample size at the higher figure of 203 per group. "
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