Vital Signs Are Not Associated with Self-Reported Acute Pain Intensity in the Emergency Department

ObjectivesThis study aimed to ascertain the association between self-reported pain intensity and vital signs in both emergency department (ED) patients and a subgroup of patients with diagnosed conditions known to produce significant pain.MethodsWe performed a retrospective analysis of real-time, archived data from an electronic medical record system at an urban teaching hospital and regional community hospital. We included consecutive ED patients ≥16 years old who had a self-reported pain intensity ≥1 as measured during triage, from March 2005 to December 2012. The primary outcome was vital signs for self-reported pain intensity levels (mild, moderate, severe) on an 11-point verbal numerical scale. Changes in pain intensity levels were also compared to variations in vital signs. Both analyses were repeated on a subgroup of patients with diagnosed conditions recognized to produce significant pain: fracture, dislocation, or renal colic.ResultsWe included 153,567 patients (mean age of 48.4±19.3 years; 55.5% women) triaged with pain (median intensity of 7/10±3). Of these, 8.9% of patients had diagnosed conditions recognized to produce significant pain. From the total sample, the difference between mild and severe pain categories was 2.7 beats/minutes (95% CI: 2.4−3.0) for heart rate and 0.13 mm Hg (95% CI: -0.26−0.52) for systolic blood pressure. These differences generated small effect sizes and were not clinically significant. Results were similar for patients who experienced changes in pain categories and for those conditions recognized to produce significant pain.ConclusionHealth care professionals cannot use vital signs to estimate or substantiate self-reported pain intensity levels or changes over time.