The choice of pain assessment scale influences emergency department triage grading

Objectives: To evaluate agreement between visual analog scale (VAS) and verbal numeric scale (VNS) pain assessments and explore whether using one scale or the other affects triage grading. Method: Prospective descriptive observational study that included patients over the age of 14 years who came to the emergency department with pain. The patients assessed pain on both a VAS and a VNS. Information was input to a database for descriptive statistics (frequencies) and analysis (Levene test, analysis of variance, and the Lin correlation coefficient). Passing-Bablock regression was used; 95% CIs were calculated. Results: The mean (SD) VAS rating was 6.27 (2.02) (95% CI, 5.91-6.62). The mean VNS rating was 7.54 (1.94) (95% CI,7.20-7.88) (P<0.001). The Lin correlation coefficient of 0.652 indicated a moderate-to-good level of agreement between scales. When the VAS pain rating was used as the basis for triage, a priority level 3 was assigned to 89 patients (69.5%) and a level 2 priority to 25 (19.5%). When the VNS pain rating was the basis for triage, 53 patients (41.4%) were assigned to level 3 priority and 70 (54.7%) to level 2 priority (P<0.001). Conclusions: The VAS and VNS pain rating instruments are not interchangeable. Pain assessments are higher when the VNS is used. We advise use of the VAS in the ED for triage and until the patient is discharged.