Emergency Department Vital Signs and Outcomes After Discharge

Vital signs are critical markers of illness severity in the emergency department (ED). Providers need to understand the abnormal vital signs in older adults that are problematic. We hypothesized that in patients age > 65 years discharged from the ED, there are abnormal vital signs that are associated with an admission to an inpatient bed within 7 days of discharge.

We conducted a retrospective cohort study using data from a regional integrated health system of members age > 65 years during the years 2009 to 2010. We used univariate contingency tables to assess the relationship between hospital admission within 7 days of discharge and vital sign (including systolic blood pressure [sBP], heart rate [HR], body temperature, and pulse oximetry [SpO₂ ] values measured closest to discharge) using standard thresholds for abnormal and thresholds derived from the study data.

Of 104,025 ED discharges, 4,638 (4.5%) were followed by inpatient admission within 7 days. Vital signs had a greater odds of admission beyond a single cutoff. The vital signs with at least twice the odds of admission were sBP < 97 mm Hg (odds ratio [OR] = 2.02, 95% CI = 1.57-2.60), HR > 101 beats/min (OR = 2.00 95% CI = 1.75-2.29), body temperature > 37.3°C (OR = 2.14, 95% CI = 1.90-2.41), and pulse oximetry < 92 SpO₂ (OR = 2.04, 95% CI = 1.55-2.68). Patients with two vital sign abnormalities per the analysis had the highest odds of admission. A majority of patients discharged with abnormal vital signs per the analysis were not admitted within 7 days of ED discharge.

While we found a majority of patients discharged with abnormal vital signs as defined by the analysis, not to be admitted after discharge, we identified vital signs associated with at least twice the odds of admission.