Non-invasive assessment of fluid responsiveness to guide fluid therapy in patients with sepsis in the emergency department: a prospective cohort study.

Background: Little is known about optimal fluid therapy for patients with sepsis without shock who present to the ED. In this study, we aimed to quantify the effect of a fluid challenge on non-invasively measured Cardiac Index (CI) in patients presenting with sepsis without shock.

Methods: In a prospective cohort study, CI, stroke volume (SV) and systemic vascular resistance (SVR) were measured non-invasively in 30 patients presenting with sepsis without shock to the ED of a large teaching hospital in the Netherlands between May 2018 and March 2019 using the ClearSight system. After baseline measurements were performed, a passive leg raise (PLR) was done to simulate a fluid bolus. Measurements were then repeated 30, 60, 90 and 120 s after PLR. Finally, a standardised 500 mL NaCl 0.9% intravenous bolus was administered after which final measurements were done. Fluid responsiveness was defined as >15% increase in CI after a standardised fluid challenge.

Measurements And Main Results: Seven out of 30 (23%) patients demonstrated a >15% increase in CI after PLR and after a 500 mL fluid bolus. Fluid responders had a higher estimated glomerular filtration rate (eGFR) (64 (44-78) vs 37 (23-47), p=0.009) but otherwise similar patient and treatment characteristics as non-responders. Baseline measurements of cardiac output (CO), CI, SV and SVR were unrelated to PLR fluid responsiveness. The change in CI after PLR was strongly positive correlated to the change in CI after a 500 mL NaCl 0.9% fluid bolus (r=0.88, p<0.001).

Conclusion: The results of the present study demonstrate that in patients with sepsis in the absence of shock, three out of four patients do not demonstrate a clinically relevant increase in CI after a standardised fluid challenge. Non-invasive CO monitoring in combination with a PLR test has the potential to identify patients who might benefit from fluid resuscitation and may contribute to a better tailored treatment of these patients.