Changes in heart rate do not correlate with changes in pain intensity in emergency department patients

The objective of this study was to determine the correlation, if any, between change in heart rate (HR) and change in pain in Emergency Department (ED) patients. This was a prospective, observational study of a convenience sample of patients presenting to an academic ED with pain. Heart rate and pain intensity (using a 100-mm visual analog scale) were determined at time of triage, 30 min post pain treatment, and at discharge. The correlation between change in HR and change in pain was determined using the Pearson correlation coefficient. Nine hundred seventy-five patients were enrolled in the study. The Pearson rho for 1143 correlations between change in HR and change in pain was 0.08 (95% CI 0.03-0.13). This study suggests that there is a poor correlation between change in pain intensity and change in heart rate among ED patients with acute pain.