Blood pressure variability as an indicator of sepsis severity in adult emergency department patients.

STUDY OBJECTIVE: Quantify the correlation between blood pressure variability (BPV) and markers of illness severity: serum lactate (LAC) or Sequential Organ Failure Assessment (SOFA) scores. METHODS: We performed a secondary analysis of data from a prospective, observational study evaluating fluid resuscitation on adult, septic, ED patients. Vital signs and fluid infusion volumes were recorded every 15min during the 3h following ED arrival. BPV was assessed via average real variability (ARV): the average of the absolute differences between consecutive BP measurements. ARV was calculated for the time periods before and after 3 fluid infusion milestones: 10-, 20-, and 30-mL/kg total body weight (TBW). Spearman's rho correlation coefficient analysis was utilized. A p-value<0.05 was considered statistically significant. RESULTS: Forty patients were included. Mean fluid infusion was 33.7mL/kg TBW (SD 22.1). All patients received fluid infusion≥10mL/kg TBW, 25 patients received fluid infusion>20mL/kg TBW, and 16 patients received fluid infusion>30mL/kg TBW. Mean initial LAC was 4.0mmol/L (SD 3.2). Mean repeat LAC was 3.1mmol/L (SD 3.2), obtained an average of 6.6h (SD 5.3) later. Mean SOFA score was 7.0 (SD 4.4). BPV correlated with both follow-up LAC (r=0.564; p=0.023) and SOFA score (r=0.544; p=0.024) among the cohort that received a fluid infusion>20-mL/kg TBW. CONCLUSION: With the finding of a positive correlation between BPV and markers of illness severity (LAC and SOFA scores), this pilot study introduces BPV analysis as a real-time, non-invasive tool for continuous sepsis monitoring in the ED.