The optimal method to administer the visual analogue scale (vas)

Introduction. The VAS is commonly used as a tool to quantify pain intensity. There is controversy as to the optimal way to administer the VAS. Some investigators recommend that the VAS should be administered de novo, i.e., each time the patient completes the scale the previous score should not be available.1 Other investigators recommend that the previous scores should be made available to the patient.2 This randomized, prospective study was undertaken to determine if the method of administration affects the VAS score. Methods. Following IRB approval and informed consent, 34 patients scheduled for abdominal surgery and who requested the use of a patient controlled analgesia pump for postoperative pain relief were randomized to one of two groups. All patients completed a VAS on the morning of postoperative day one. That same afternoon, patients in group I completed a new VAS and patients in group II completed the VAS on their original form. All patients were also asked to compare their current level of pain to what it was in the morning as more, less, or the same. A change of more then 10 mm in VAS score was considered a real change. Results were analyzed using chi-square and comparison of proportions, and p < 0.05 was considered significant. Results. Thirty four patients were studied, 17 in each group. There were no significant differences between the groups in sex or mean weight, height, or age. In Group I, there were five discordant ratings, i.e., the direction of VAS change was different from the direction of change in the patient's subjective pain rating. In Group II, there were three discordant cases. GROUP I GROUP II Descriptive Rating Descriptive Rating Change in VAS More Same Less Change in VAS More Same Less Increase 302 Increase 3 1 0 No change 023 No change 25 0 Decrease 007 Decrease 006 Discordant cases Discussion. We did not find a difference in the number of discordant cases between Group I and Group II patients. It would appear, at this early stage in the study, that it does not make a difference if the VAS is administered de novo or not. References.