Reliability of the Visual Analog Scale for Measurement of Acute Pain

Abstract

Abstract. Objective: Reliable and valid measures of pain are needed to advance research initiatives on appropriate and effective use of analgesia in the emergency department (ED). The reliability of visual analog scale (VAS) scores has not been demonstrated in the acute setting where pain fluctuation might be greater than for chronic pain. The objective of the study was to assess the reliability of the VAS for measurement of acute pain. Methods: This was a prospective convenience sample of adults with acute pain presenting to two EDs. Intraclass correlation coefficients (ICCs) with 95% confidence intervals (95% CIs) and a Bland-Altman analysis were used to assess reliability of paired VAS measurements obtained 1 minute apart every 30 minutes over two hours. Results:The summary ICC for all paired VAS scores was 0.97 [95% CI = 0.96 to 0.98]. The Bland-Altman analysis showed that 50% of the paired measurements were within 2 mm of one another, 90% were within 9 mm, and 95% were within 16 mm. The paired measurements were more reproducible at the extremes of pain intensity than at moderate levels of pain. Conclusions: Reliability of the VAS for acute pain measurement as assessed by the ICC appears to be high. Ninety percent of the pain ratings were reproducible within 9 mm. These data suggest that the VAS is sufficiently reliable to be used to assess acute pain. been done to assess the reliability of the VAS for measurement of acute pain. The few studies that have explicitly assessed the reproducibility of VAS measures of pain focused on chronic or postoperative pain, and most examined the correlation between repeat VAS measures. A study of a mechanical version of a VAS (a tool with a 10-cm ruler and a marker that the patient moves to the point indicating his or her intensity of pain) used by patients with rheumatoid arthritis found a correlation of 0.88 between two measures taken two hours apart. 5 Studies that examined the correlation between a vertically oriented VAS for pain with a horizontally oriented VAS found correlations of 0.99 and 0.91 when they were given within 10 minutes of each other 2,3 to patients with a variety of rheumatic diseases.Although calculation of the Pearson productmoment correlation coefficient has often been used to assess VAS reliability, 2-5 this method has been justly criticized as providing an inflated estimate.9-11 A more appropriate formulation of the correlation coefficient 12 and an analysis of the actual difference between repeated measures have both been recommended. 9 Our primary goal in this study was to assess the reliability of the VAS in acute pain using methodologically appropriate statistical techniques.

Periotome as an Aid to Atraumatic Extraction: A Comparative Double Blind Randomized Controlled Trial

“…During the preoperative phase, pain was assessed using visual analogue scale before the administration of LA [13,14]. During the intraoperative phase, duration of procedure was calculated from the onset of local anaesthesia till the completion of tooth extraction.…”

“…Immediate post-op, complications, if any, were recorded. Gingival lacerations were graded using the following scale: Postoperatively, patients were instructed to measure the intensity of postoperative pain throughout the period of 7 days (3rd h, 6th h, 24th h, 7th day) on visual analogue scale [13,14]. They also had to record the number and frequency of analgesics consumed and any other complications.…”

Selective vs argon laser trabeculoplasty: hypotensive efficacy, anterior chamber inflammation, and postoperative pain

“…Measured flare values are expressed in photon counts per millisecond given by the instrument. In the immediate postoperative check-up and at 24 h, a 0-to-10 visual analogue scale [15][16][17] (VAS, UPSA Institute) was used for the patients to determine objectively the degree of pain suffered during treatment and the first postoperative hours. The patients were also asked questions of the type: how much pain or discomfort did treatment cause?…”

Efficacy of vasectomy reversal according to patency for the surgical treatment of postvasectomy pain syndrome

“…Intraoperative vasal fluid detection and postoperative recovery of fertility may also have had some bearing on surgical outcome and patient satisfaction. Although VAS is generally regarded as a valid and reliable tool for chronic pain measurement, 29 these scores could conceivably reflect long-term memory or other inaccuracies, and correlation between VNRS and VAS has been imperfect in previous studies. 30 Results of patency may influence VAS.…”