Prediction of Fluid Responsiveness Using the Femoral Vein-to-Artery Diameter Ratio

NCT07546656 | Not Yet Recruiting

• 1 other identifier: E-24687260-604.01-1615271
• Study Type: observational
• Target: 100
• Locations: 1 country
• Sites: 1

Brief Summary

This prospective single-center observational study aims to evaluate whether the ultrasound-measured femoral vein-to-femoral artery diameter ratio can predict fluid responsiveness in mechanically ventilated adult intensive care patients with acute circulatory failure or shock. Only patients who already have PiCCO monitoring as part of routine clinical care and for whom a fluid challenge is clinically indicated will be included. No additional invasive procedure will be performed for study purposes. Cardiac index will be measured with PiCCO before and after administration of 500 mL balanced crystalloid over 10 minutes, and femoral vein and femoral artery diameters will be measured by bedside ultrasonography. Fluid responsiveness will be defined as an increase of more than 10% in cardiac index after fluid administration. The study will assess the diagnostic performance of the femoral vein-to-femoral artery diameter ratio as a practical bedside parameter to support hemodynamic decision-making in critically ill patients.

Conditions

Fluid Responsiveness; Acute Circulatory Failure; Shock

Keywords

Fluid Responsiveness; Shock; Acute Circulatory Failure; Hemodynamic Monitoring; Ultrasonography; Femoral Vein; Femoral Artery; PiCCO

Outcome Measures

Primary Outcomes (1)

• Diagnostic performance of the baseline femoral vein-to-femoral artery diameter ratio for predicting fluid responsiveness

  Diagnostic performance of the baseline ultrasound-measured femoral vein-to-femoral artery diameter ratio in identifying fluid responders, assessed by receiver operating characteristic analysis (area under the curve). Fluid responsiveness will be defined as an increase of more than 10% in cardiac index after administration of 500 mL balanced crystalloid over 10 minutes.

  Baseline assessment before fluid challenge, with responder status determined 10 minutes after completion of the fluid challenge

Secondary Outcomes (1)

• Percent change in cardiac index after fluid challenge

  Before fluid challenge and 10 minutes after completion of the fluid challenge

Interventions

Ultrasound Measurement of Femoral Vein-to-Femoral Artery Diameter Ratio DIAGNOSTIC_TEST

Bedside ultrasonographic measurement of femoral vein and femoral artery diameters at the same anatomical level proximal to the femoral artery bifurcation, with at least three repeated measurements and calculation of the femoral vein-to-femoral artery diameter ratio before and after a clinically indicated fluid challenge.

Eligibility Criteria

• Age: 18 Years+
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)
• Sampling Method: Non-Probability Sample

Study Population

The study population consists of adult intensive care unit patients with acute circulatory failure or shock who are receiving invasive mechanical ventilation and for whom the responsible intensive care physician has determined a clinical indication for a fluid challenge. Only patients who already have PiCCO monitoring in place as part of routine clinical care and in whom femoral vein and femoral artery ultrasonographic measurements can be obtained will be enrolled.

You may qualify if:

• Adult patients aged 18 years or older
• Admission to the intensive care unit where the study is being conducted
• Receiving invasive mechanical ventilation
• Clinical indication for a fluid challenge due to acute circulatory failure or shock, as determined by the responsible intensive care physician
• PiCCO monitoring already in place as part of routine clinical care
• Clinical conditions allowing collection of pre- and post-fluid challenge cardiac index and ultrasonographic measurements
• Technical feasibility of femoral vein and femoral artery diameter measurements by ultrasonography

You may not qualify if:

• Age younger than 18 years
• Failure to obtain written informed consent from the patient or legally authorized representative before enrollment
• Absence of PiCCO monitoring as part of routine clinical care or no clinical plan for fluid challenge
• Inability to complete pre- and post-fluid challenge measurements (e.g., early death, urgent surgery, transfer)
• Local conditions preventing reliable femoral ultrasonographic assessment, including open wound, infection, dressing, major anatomic obstacle, poor image quality, known femoral vein thrombosis, or severe vascular pathology on the relevant side
• Conditions likely to significantly impair the reliability of thermodilution measurements (e.g., severe tricuspid regurgitation or significant intracardiac shunt)
• Major treatment changes during the fluid challenge that preclude comparable measurements (e.g., major vasopressor dose change, major ventilator setting change, new arrhythmia)
• Missing or inadequate data judged by the investigators to compromise data integrity, including absence of measurements required for the primary outcome

Sponsors & Collaborators

• Istanbul University - Cerrahpasa: lead

Study Sites (1)

Istanbul University Cerrahpasa Medical Faculty

Istanbul, Istanbul, Turkey (Türkiye)

Location

MeSH Terms

Conditions

Shock

Condition Hierarchy (Ancestors)

Pathologic Processes; Pathological Conditions, Signs and Symptoms

Central Study Contacts

mert katılmış

CONTACT

+905346430560; mertkatilmis97@gmail.com

Study Design

• Study Type: observational
• Observational Model: COHORT
• Time Perspective: PROSPECTIVE
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Resident Physician, Department of Anesthesiology and Reanimation

Study Record Dates

• First Submitted: April 16, 2026
• First Posted: April 23, 2026
• Study Start: May 1, 2026
• Primary Completion (Estimated): January 31, 2027
• Study Completion (Estimated): March 1, 2027
• Last Updated: April 23, 2026

Record last verified: 2026-04

Data Sharing

• IPD Sharing: Will not share

Locations

TU (1)