Fluid tolerance in septic shock: Femoral vein pulsatility versus VExUS score in a cross-sectional study.

Abstract

Background: Excessive fluid resuscitation in patients with septic shock is associated with acute organ injury and increased mortality. Accurate assessment of fluid tolerance is therefore essential. Right cardiac chamber fluid tolerance can be evaluated by estimating the right atrial pressure using central venous catheters, inferior vena cava (IVC) measurements, Venous Excess Ultrasound (VExUS) scores and femoral vein pulsatility (FVP).

Objectives: To assess the correlation between FVP and VExUS score in evaluating fluid intolerance and venous congestion in patients with septic shock; the correlation of FVP and VExUS score with central venous pressure (CVP); and to evaluate the effect of positive pressure ventilation on the relationship between FVP and VExUS score.

Methods: In this observational cross-sectional study, 80 participants were assessed for fluid tolerance using VExUS scores and FVP. CVP, maximum and minimum IVC diameters and IVC dynamicity were regarded as the gold standard and used as reference.

Results: FVP showed moderate agreement with VExUS score (Kappa=0.55; p<0.001). Both FVP and VExUS score demonstrated the ability to predict CVP values ≥17 cmH₂O with overall accuracies of 70% and 77.5%, respectively (p<0.001). A CVP ≥17.5 cmH₂O predicted severely congested femoral veins with a sensitivity of 70% and specificity of 90%, whereas a CVP ≥18.5 cmH₂O predicted VExUS grade 3 with a sensitivity of 66.7% and specificity of 83.3%. Maximum IVC diameter accurately predicted abnormal femoral vein Doppler findings, with an overall accuracy of 82.5%.

Conclusion: A pulsatile femoral vein pattern indicates fluid intolerance in patients with septic shock, providing an additional marker for assessing fluid status. Doppler assessment of the femoral vein offers advantages of easier anatomical accessibility and a shorter learning curve compared with other methods.

Contribution of the study: This study evaluated a simple rapid tool (femoral vein pulsability) in assessing volume state and fluid tolerance in septic patients in comparison with VExsus.