Fluid ResponsivenessNCT07546656
Prediction of Fluid Responsiveness Using the Femoral Vein-to-Artery Diameter Ratio
An observational study of Fluid Responsiveness and Acute Circulatory Failure, run by Istanbul University - Cerrahpasa at 1 site in Turkey (Türkiye).
Trial 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. Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Fluid Responsiveness, Acute Circulatory Failure, Shock
- What is being tested?
- Ultrasound Measurement of Femoral Vein-to-Femoral Artery Diameter Ratio
- How many people
- 100 participants
- Where
- 1 siteTurkey (Türkiye)
- Study dates
- 1 May 2026to 1 Mar 2027
- Phase
- Observational
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
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.
Who may be able to join
- 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
Who cannot join
- 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
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
Turkey (Türkiye)1 site, 1 recruiting
- Recruiting
Istanbul University Cerrahpasa Medical Faculty
Istanbul, Istanbul
mert katılmış, medical doctor, +905346430560, mertkatilmis97@gmail.com
About this study
Official title: Prediction of Fluid Responsiveness Using the Femoral Vein-to-Artery Diameter Ratio: A Prospective Observational Study
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.
Read the detailed description
Acute circulatory failure and shock are common conditions in the intensive care unit, and fluid administration remains a key component of hemodynamic management. However, unnecessary fluid loading may worsen tissue edema, oxygenation, and organ function. Therefore, practical bedside tools that help identify fluid-responsive patients are clinically important.
The aim of this study is to evaluate the clinical utility of the ultrasound-measured femoral vein-to-femoral artery diameter ratio in predicting fluid responsiveness in mechanically ventilated adult ICU patients with acute circulatory failure or shock. This is a prospective, single-center, observational study.
No additional invasive intervention will be performed for research purposes. PiCCO monitoring will not be initiated for study reasons; only patients who already have PiCCO monitoring as part of routine ICU management and who are scheduled to undergo a clinically indicated fluid challenge will be enrolled.
Before the fluid challenge, cardiac index will be recorded using PiCCO, and femoral vein and femoral artery diameters will be measured by bedside ultrasonography at the same anatomical level proximal to the femoral artery bifurcation. Each ultrasound measurement will be repeated at least three times, and the mean value will be recorded. A fluid challenge consisting of 500 mL balanced crystalloid administered over 10 minutes will then be performed according to routine clinical care. After the fluid challenge, cardiac index and the femoral vein-to-femoral artery diameter ratio will be reassessed using the same methods.
Fluid responsiveness will be defined as an increase of more than 10% in cardiac index after fluid administration. Responders and non-responders will be compared, and the diagnostic performance of the femoral vein-to-femoral artery diameter ratio will be analyzed.
Demographic data, baseline clinical findings, hemodynamic measurements, and ultrasound measurements will be collected and analyzed. Appropriate descriptive statistics, group comparisons, and diagnostic performance analyses will be used to evaluate the discriminative ability of the femoral vein-to-femoral artery diameter ratio. All data will be de-identified and handled in accordance with patient confidentiality principles.
- Conditions
- Fluid Responsiveness, Acute Circulatory Failure, Shock
- Being tested
- Ultrasound Measurement of Femoral Vein-to-Femoral Artery Diameter Ratio
- Keywords
- Fluid Responsiveness, Shock, Acute Circulatory Failure, Hemodynamic Monitoring, Ultrasonography, Femoral Vein, Femoral Artery, PiCCO
- Medical subject headings
- Shock
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Ultrasound Measurement of Femoral Vein-to-Femoral Artery Diameter RatioDiagnostic 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.
What is being measured
The primary outcome is the main question the study is designed to answer.
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.
Measured: 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
Percent change in PiCCO-derived cardiac index after administration of 500 mL balanced crystalloid over 10 minutes.
Measured: Before fluid challenge and 10 minutes after completion of the fluid challenge
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted23 Apr 2026
- Study start1 May 2026
- Primary completion31 Jan 2027 (estimated)
- Study completion1 Mar 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Fluid ResponsivenessStudies of the same condition, open and under way.
- More trials run by Istanbul University - CerrahpasaThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Observational
- Observational model
- Cohort
- Time perspective
- Prospective
- Enrolment
- 100 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Istanbul University - Cerrahpasa
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, mert katılmış, Istanbul University - Cerrahpasa
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07546656
- Sponsor's protocol ID
- E-24687260-604.01-1615271
- Status last verified
- May 2026
- First submitted
- 16 Apr 2026
- Last updated
- 11 May 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 11 May 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Prediction of Fluid Responsiveness Using the Femoral Vein-to-Artery Diameter Ratio: A Prospective Observational Study
- ClinicalTrials.gov ID
- NCT07546656
- Acronym / sponsor ID
- E-24687260-604.01-1615271
- Conditions
- Fluid Responsiveness, Acute Circulatory Failure, Shock
- Keywords
- Fluid Responsiveness, Shock, Acute Circulatory Failure, Hemodynamic Monitoring, Ultrasonography, Femoral Vein, Femoral Artery, PiCCO
- Study type
- Observational
- Recruitment status
- Recruiting
- Enrolment
- 100 participants (estimated)
- Lead sponsor
- Istanbul University - CerrahpasaUniversity, hospital or other
- Study start
- 1 May 2026 (actual)
- Primary completion
- 31 Jan 2027 (estimated)
- Study completion
- 1 Mar 2027 (estimated)
- First posted
- 23 Apr 2026 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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.
Detailed description
Acute circulatory failure and shock are common conditions in the intensive care unit, and fluid administration remains a key component of hemodynamic management. However, unnecessary fluid loading may worsen tissue edema, oxygenation, and organ function. Therefore, practical bedside tools that help identify fluid-responsive patients are clinically important.
The aim of this study is to evaluate the clinical utility of the ultrasound-measured femoral vein-to-femoral artery diameter ratio in predicting fluid responsiveness in mechanically ventilated adult ICU patients with acute circulatory failure or shock. This is a prospective, single-center, observational study.
No additional invasive intervention will be performed for research purposes. PiCCO monitoring will not be initiated for study reasons; only patients who already have PiCCO monitoring as part of routine ICU management and who are scheduled to undergo a clinically indicated fluid challenge will be enrolled.
Before the fluid challenge, cardiac index will be recorded using PiCCO, and femoral vein and femoral artery diameters will be measured by bedside ultrasonography at the same anatomical level proximal to the femoral artery bifurcation. Each ultrasound measurement will be repeated at least three times, and the mean value will be recorded. A fluid challenge consisting of 500 mL balanced crystalloid administered over 10 minutes will then be performed according to routine clinical care. After the fluid challenge, cardiac index and the femoral vein-to-femoral artery diameter ratio will be reassessed using the same methods.
Fluid responsiveness will be defined as an increase of more than 10% in cardiac index after fluid administration. Responders and non-responders will be compared, and the diagnostic performance of the femoral vein-to-femoral artery diameter ratio will be analyzed.
Demographic data, baseline clinical findings, hemodynamic measurements, and ultrasound measurements will be collected and analyzed. Appropriate descriptive statistics, group comparisons, and diagnostic performance analyses will be used to evaluate the discriminative ability of the femoral vein-to-femoral artery diameter ratio. All data will be de-identified and handled in accordance with patient confidentiality principles.
Study design
- Observational model
- Cohort
- Time perspective
- Prospective
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
- 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.
Key inclusion criteria (7 listed)
- 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
Key exclusion criteria (8 listed)
- 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
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Ultrasound Measurement of Femoral Vein-to-Femoral Artery Diameter RatioBedside 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. | Diagnostic test | – |
Primary outcome
Diagnostic performance of the baseline femoral vein-to-femoral artery diameter ratio for predicting fluid responsiveness
Time frame: Baseline assessment before fluid challenge, with responder status determined 10 minutes after completion of the fluid challenge
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.
1 secondary outcome
Percent change in cardiac index after fluid challenge
Time frame: Before fluid challenge and 10 minutes after completion of the fluid challenge
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 11 May 2026.
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of Fluid Responsiveness and Acute Circulatory Failure, run by Istanbul University - Cerrahpasa at 1 site in Turkey (Türkiye).
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 7 inclusion and 8 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 11 May 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Turkey (Türkiye). Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact mert katılmış (+905346430560, mertkatilmis97@gmail.com), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Diagnostic performance of the baseline femoral vein-to-femoral artery diameter ratio for predicting fluid responsiveness (time frame: Baseline assessment before fluid challenge, with responder status determined 10 minutes after completion of the fluid challenge). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 11 May 2026.