Measuring the dyspnea of decompensated heart failure with a visual analog scale: how much improvement is meaningful?

Patients presenting to the emergency department with heart failure are evaluated based on the subjective sensation of dyspnea. In this study, the authors sought to determine the change in dyspnea, measured by a visual analog scale (VAS), which is associated with a meaningful change in the patient's perception and the effect of dyspnea severity on the VAS. In this prospective, observational study the authors defined a meaningful change in VAS dyspnea as the difference between VAS scores when patients reported "a little less difficulty breathing" or "a little more difficulty breathing." Seventy-four patients were evaluated, and the mean for a meaningful change in VAS was 21.1 mm (95% confidence interval, 12.3-29.9 mm). Patients that recorded higher index VAS scores had a significantly greater change in VAS. VAS scores and the changes with treatment provide the treating physician with another means to assess the effects of their interventions.