# Femoral vein Doppler ultrasound for assessing venous congestion and right heart function: a scoping review

## TL;DR

This review explores using femoral vein Doppler ultrasound to assess venous congestion and right heart function in critically ill patients, finding it promising but needing standardization.

## Contribution

The study maps and synthesizes evidence on femoral vein Doppler ultrasound as a novel, accessible tool for assessing right heart function and volume status.

## Key findings

- CFV Doppler ultrasound showed weak-to-moderate correlations with invasive central venous pressure and echocardiographic measures.
- Abnormal CFV patterns were linked to postoperative complications like acute kidney injury and ICU mortality in some studies.
- Variability in acquisition protocols and thresholds limits current clinical applicability of CFV Doppler ultrasound.

## Abstract

Venous congestion is a major contributor to organ dysfunction in critically ill and perioperative patients. While Doppler-based ultrasound strategies such as VExUS are the focus of growing clinical and research interest, the common femoral vein (CFV) is a promising, easily accessible alternative window for assessing right heart function and volume status.

To map and synthesize current evidence on the use of common femoral vein (CFV) Doppler ultrasound to assess venous congestion, right heart function, and intravascular volume status in adult patients across perioperative, critical care, heart failure, and emergency care settings.

Scoping review conducted according to the PRISMA-ScR guideline.

PubMed, Embase, Scopus, and the Cochrane Library were searched from inception to August 2025. We charted clinical setting, CFV Doppler/diameter parameters, acquisition protocol details, reference standards (invasive pressures and imaging-based surrogates), and reported associations with hemodynamic measures and clinical outcomes. Two reviewers independently screened records and extracted data.

Nineteen observational studies (n = 2146) were included. CFV pulsatility or waveform morphology was assessed in 10/19 studies; 5/19 reported quantitative pulsatility indices or retrograde-flow thresholds, 5/19 evaluated femoral vein diameter/collapsibility, and 1/19 proposed derived indices. Most studies compared CFV measures with invasive central venous pressure (CVP) or echocardiographic surrogates; when correlation coefficients were reported, associations were weak-to-moderate (e.g., r = 0.66 for CFV diameter vs CVP; r = − 0.476 for minimum velocity vs CVP). Only a minority of studies assessed clinical outcomes, and abnormal CFV patterns were variably associated with postoperative complications, including acute kidney injury, delirium and, in ICU cohorts, longer ICU length of stay or mortality. Acquisition protocols and waveform interpretation criteria varied across studies, with heterogeneous definitions and thresholds.

CFV Doppler is a feasible and accessible tool for congestion assessment, with promising correlations to invasive measures. However, variability in acquisition protocols, waveform definitions, and thresholds limits its current applicability. Standardization and prospective validation in high-risk populations are needed.

The online version contains supplementary material available at 10.1186/s40635-026-00856-x.