Table 3.

Adjunctive physiology-guided tools for fluid responsiveness and congestion assessment in ED sepsis.

Tool	Primary bedside question	Main strength	Key ED limitation
Passive leg raise with LVOT VTI or comparable aortic Doppler surrogate	Is the patient likely to increase stroke volume with additional fluid?	Dynamic, reversible, and directly linked to change in flow	Requires Doppler skill and interpretable windows; rhythm/respiratory factors may confound interpretation
Inferior vena cava size and respiratory variation	Provides preload-related context; should not be used alone to decide for or against further fluid	Fast and widely available	Strongly affected by ventilation, RV dysfunction, intra-abdominal pressure, and loading conditions
Lung ultrasound B-line trend	Is pulmonary congestion or interstitial burden increasing?	Rapid, repeatable, and easy to trend serially	Not specific for fluid alone; ARDS, pneumonia, and interstitial lung disease may produce overlapping patterns
Venous Doppler/VExUS	Is systemic venous congestion developing?	Provides a structured congestion signal beyond the lungs	Optional advanced add-on only; ED sepsis evidence remains limited; acquisition and interpretation require additional training

ARDS, acute respiratory distress syndrome; ED, emergency department; LVOT, left ventricular outflow tract; RV, right ventricle/right ventricular; VExUS, venous excess ultrasound; VTI, velocity-time integral.