Association Between Intravenous Fluid Bolus and Biomarker Trajectory During Prehospital Care

Abstract

Background: Patients with acute illness who receive intravenous (IV) fluids prior to hospital arrival may have a lower in-hospital mortality. To better understand whether this is a direct treatment effect or epiphenomenon of downstream care, we tested the association between a prehospital fluid bolus and the change in inflammatory cytokines measured at prehospital and emergency department timepoints in a sample of non-trauma, non-cardiac arrest patients at risk for critical illness. Methods: In a prospective cohort study, we screened 4,013 non-trauma, non-cardiac arrest encounters transported by City of Pittsburgh Emergency Medical Services (EMS) to 2 hospitals from August 2013 to February 2014. In 345 patients, we measured prehospital biomarkers (IL-6, IL-10, and TNF) at 2 time points: the time of prehospital IV access placement by EMS and at ED arrival. We determined the relative change for marker X as: ([X_ED – X_EMS]/X_EMS). We determined the risk-adjusted association between prehospital IV fluid bolus and relative change for each marker using multivariable linear regression. Results: Among 345 patients, 88 (26%) received a prehospital IV fluid bolus and 257 (74%) did not. Compared to patients who did not receive prehospital fluids, median prehospital IL-6 was greater initially in subjects receiving a prehospital IV fluid bolus (22.3 [IQR 6.4–113] vs. 11.5 [IQR 5.5–47.6]). Prehospital IL-10 and TNF were similar in both groups (IL-10: 3.5 [IQR 2.2–25.6] vs. 3.0 [IQR 1.9–9.0]; TNF: 7.5 [IQR 6.4–10.4] vs. 6.9 [IQR 6.0–8.3]). After adjustment for demographics, illness severity, and prehospital transport time, we observed a relative decrease in IL-6 at hospital arrival in those receiving a prehospital fluid bolus (adjusted β = −10.0, 95% CI: −19.4, −0.6, p = 0.04), but we did not detect a significant change in IL-10 (p = 0.34) or TNF (p = 0.53). Conclusions: Among non-trauma, non-cardiac arrest patients at risk for critical illness, a prehospital IV fluid bolus was associated with a relative decrease in IL-6, but not IL-10 or TNF.

Key words:

• sepsis
• prehospital
• biomarkers
• trajectory
• fluids

Acknowledgments

We would like to acknowledge the significant contribution of the patients, families, researchers, clinical staff, City of Pittsburgh EMS, UPMC Prehospital services, Biostatistical and Data Management Core (BDMC), and the Clinical Research Investigation and Systems Modeling of Acute Illness (CRISMA) Center of the University of Pittsburgh Department of Critical Care Medicine.

Conflicts of Interest

The authors report no disclosures, conflict of interests or relevant financial interests related to the content of the manuscript.

Additional information

Funding

C.W. Seymour was supported in part by grants from the National Institutes of Health (R35GM119519, K23GM104022). O.M. Peck Palmer was supported in part by the University of Pittsburgh School of Medicine, Dean’s Faculty Advancement Award. The funding source had no role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; and preparation, review, or approval of the manuscript.