Hemodynamic ChangesPSM-PVC-RITVENNCT07499388
Assessment of Venous Return During Volume Expansion: a Prospective Observational Study
An observational study of Hemodynamic Changes, run by Università Politecnica delle Marche at 1 site in Italy.
Trial summary
According to Guyton's model of venous return, the fluids that effectively increase cardiac output are those that, once administered, increase the vascular stressed volume, thereby increasing the mean systemic filling pressure (Pms) without increasing the central venous pressure (CVP). Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Hemodynamic Changes
- What is being tested?
- Fluid challenge of 500ml of crystalloid
- Type of treatment
- Injection or infusion
- How many people
- 45 participants
- Where
- 1 siteItaly
- Study dates
- 1 Mar 2025to Jul 2026
- 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: Critically ill patients
Who may be able to join
- Critically ill patients admitted to the intensive care unit
- Invasive or minimally invasive hemodynamic monitoring
- Clinical indication for volume expansion with 500 mL of crystalloids
Who cannot join
- Suspected or confirmed pregnancy
- Clinical conditions that may reduce the reliability of hemodynamic monitoring:
- Severe aortic stenosis or regurgitation
- Severe mitral stenosis or regurgitation
- History of peripheral arterial disease
- Clinical contraindications to the supine position
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
Italy1 site, 1 recruiting
- Recruiting
AOU delle Marche
Ancona, 60123
Abele Pr Donati, PhD, 0715963858, a.donati@univpm.it
About this study
According to Guyton's model of venous return, the fluids that effectively increase cardiac output are those that, once administered, increase the vascular stressed volume, thereby increasing the mean systemic filling pressure (Pms) without increasing the central venous pressure (CVP). In this way, since the gradient between Pms and CVP increases, venous return-and consequently cardiac output-also increases.
In cases where physiologically ineffective fluids are administered, the situation arises in which, in addition to increasing the stressed volume and thus Pms, CVP also increases. As a result, the gradient between Pms and CVP remains unchanged, and cardiac output does not increase.
The hypothesis is that only a portion of the fluids administered during volume expansion are actually effective in increasing the gradient between Pms and CVP.
- Conditions
- Hemodynamic Changes
- Being tested
- Fluid challenge of 500ml of crystalloid
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Fluid challenge of 500ml of crystalloidDrug
The mean systemic filling pressure (Pms) will be measured using the transient stop-flow arm technique, a method routinely used in clinical practice. This involves placing a non-invasive blood pressure cuff on the same arm where invasive arterial pressure is monitored via the radial artery. The cuff is inflated for one minute to temporarily occlude blood flow. At the end of this period, the invasive arterial pressure displayed on the monitor reflects the Pms. This brief interruption of blood flow does not pose significant risks to tissue perfusion.
A fluid challenge with 500 mL of crystalloids will then be performed as per clinical indication. Pms will be measured at baseline, after the infusion of 150 mL, 250 mL, 500 mL, and one hour after the end of fluid administration. Central venous pressure (CVP) and cardiac index (CI) will be continuously monitored throughout the fluid challenge.
Patients will be classified as fluid responders if stroke volume (SV) increases by more than
What is being measured
The primary outcome is the main question the study is designed to answer.
Variation of the Venous Return Gradient (Pms - CVP) in Fluid Responders
To describe the change in the venous return gradient (mean systemic filling pressure minus central venous pressure, Pms - CVP) during volume expansion with 500 mL of crystalloids in fluid responsive patients.
The fluid challenge is administered according to the clinician's indication. A total of 500 mL of crystalloids is infused over 25 minutes, corresponding to an infusion rate of 1200 mL/h.
Measured: Measurements are taken at baseline, and at 7 minutes and 30 seconds, 12 minutes and 30 seconds, and 25 minutes from the start of crystalloid infusion (corresponding to 150 mL, 250 mL, and 500 mL infused, respectively).
Secondary outcomes (9)
Venous Return Gradient Variation in Fluid Responders vs Non-Responders
To compare the change in Pms - CVP between fluid responders and non-responders during volume expansion with 500 mL of crystalloids. The fluid challenge is administered according to the clinician's indication. A total of 500 mL of crystalloids is infused over 25 minutes, corresponding to an infusion rate of 1200 mL/h.
Measured: Measurements are taken at baseline, and at 7 minutes and 30 seconds, 12 minutes and 30 seconds, and 25 minutes from the start of crystalloid infusion (corresponding to 150 mL, 250 mL, and 500 mL infused, respectively).
Venous Return Gradient Variation in the General Population
To describe the changes in Pms - CVP in the overall study population during volume expansion with 500 mL of crystalloids in fluid responsive patients. The fluid challenge is administered according to the clinician's indication. A total of 500 mL of crystalloids is infused over 25 minutes, corresponding to an infusion rate of 1200 mL/h.
Measured: Measurements are taken at baseline, and at 7 minutes and 30 seconds, 12 minutes and 30 seconds, and 25 minutes from the start of crystalloid infusion (corresponding to 150 mL, 250 mL, and 500 mL infused, respectively).
Cardiac Index Variation in the General Population
To assess changes in cardiac index in the overall study population during volume expansion with 500 mL of crystalloids. The fluid challenge is administered according to the clinician's indication. A total of 500 mL of crystalloids is infused over 25 minutes, corresponding to an infusion rate of 1200 mL/h.
Measured: Measurements are taken at baseline, and at 7 minutes and 30 seconds, 12 minutes and 30 seconds, and 25 minutes from the start of crystalloid infusion (corresponding to 150 mL, 250 mL, and 500 mL infused, respectively).
Mean Systemic Filling Pressure (Pms) Variation in the General Population
To evaluate how Pms changes in the overall population during volume expansion with 500 mL of crystalloids. The fluid challenge is administered according to the clinician's indication. A total of 500 mL of crystalloids is infused over 25 minutes, corresponding to an infusion rate of 1200 mL/h.
Measured: Measurements are taken at baseline, and at 7 minutes and 30 seconds, 12 minutes and 30 seconds, and 25 minutes from the start of crystalloid infusion (corresponding to 150 mL, 250 mL, and 500 mL infused, respectively).
Central Venous Pressure (CVP) Variation in the General Population
To describe how CVP varies in the overall population during volume expansion with 500 mL of crystalloids. The fluid challenge is administered according to the clinician's indication. A total of 500 mL of crystalloids is infused over 25 minutes, corresponding to an infusion rate of 1200 mL/h.
Measured: Measurements are taken at baseline, and at 7 minutes and 30 seconds, 12 minutes and 30 seconds, and 25 minutes from the start of crystalloid infusion (corresponding to 150 mL, 250 mL, and 500 mL infused, respectively).
Cardiac Index Variation in Fluid Responders vs Non-Responders
To compare cardiac index changes between fluid responders and non-responders during volume expansion with 500 mL of crystalloids. The fluid challenge is administered according to the clinician's indication. A total of 500 mL of crystalloids is infused over 25 minutes, corresponding to an infusion rate of 1200 mL/h.
Measured: Measurements are taken at baseline, and at 7 minutes and 30 seconds, 12 minutes and 30 seconds, and 25 minutes from the start of crystalloid infusion (corresponding to 150 mL, 250 mL, and 500 mL infused, respectively).
Mean Systemic Filling Pressure (Pms) Variation in Fluid Responders vs Non-Responders
To compare Pms changes between fluid responders and non-responders during volume expansion with 500 mL of crystalloids. The fluid challenge is administered according to the clinician's indication. A total of 500 mL of crystalloids is infused over 25 minutes, corresponding to an infusion rate of 1200 mL/h.
Measured: Measurements are taken at baseline, and at 7 minutes and 30 seconds, 12 minutes and 30 seconds, and 25 minutes from the start of crystalloid infusion (corresponding to 150 mL, 250 mL, and 500 mL infused, respectively).
Central Venous Pressure (CVP) Variation in Fluid Responders vs Non-Responders
To evaluate CVP changes in fluid responders compared to non-responders during volume expansion with 500 mL of crystalloids. The fluid challenge is administered according to the clinician's indication. A total of 500 mL of crystalloids is infused over 25 minutes, corresponding to an infusion rate of 1200 mL/h.
Measured: Measurements are taken at baseline, and at 7 minutes and 30 seconds, 12 minutes and 30 seconds, and 25 minutes from the start of crystalloid infusion (corresponding to 150 mL, 250 mL, and 500 mL infused, respectively).
Systemic Vascular Resistance (SVR) Variation in Fluid Responders vs Non-Responders
To describe and compare changes in systemic vascular resistance between fluid responders and non-responders during volume expansion with 500 mL of crystalloids. The fluid challenge is administered according to the clinician's indication. A total of 500 mL of crystalloids is infused over 25 minutes, corresponding to an infusion rate of 1200 mL/h.
Measured: Measurements are taken at baseline, and at 7 minutes and 30 seconds, 12 minutes and 30 seconds, and 25 minutes from the start of crystalloid infusion (corresponding to 150 mL, 250 mL, and 500 mL infused, respectively).
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted30 Mar 2026
- Study start1 Mar 2025
- Primary completionJul 2026 (estimated)
- Study completionJul 2026 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Hemodynamic ChangesStudies of the same condition, open and under way.
- 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
- 45 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Università Politecnica delle Marche
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Abele Donati, MD, Università Politecnica delle Marche
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07499388
- Sponsor's protocol ID
- PSM-PVC-VENRET
- Acronym
- PSM-PVC-RITVEN
- Status last verified
- Mar 2026
- First submitted
- 18 Apr 2025
- Last updated
- 30 Mar 2026
- Results posted
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Undecided
Study at a glance
From the registry record, last updated by the sponsor on 30 Mar 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Assessment of Venous Return During Volume Expansion: a Prospective Observational Study
- ClinicalTrials.gov ID
- NCT07499388
- Acronym / sponsor ID
- PSM-PVC-RITVEN / PSM-PVC-VENRET
- Conditions
- Hemodynamic Changes
- Study type
- Observational
- Recruitment status
- Recruiting
- Enrolment
- 45 participants (estimated)
- Lead sponsor
- Università Politecnica delle MarcheUniversity, hospital or other
- Study start
- 1 Mar 2025 (actual)
- Primary completion
- Jul 2026 (estimated)
- Study completion
- Jul 2026 (estimated)
- First posted
- 30 Mar 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.
According to Guyton's model of venous return, the fluids that effectively increase cardiac output are those that, once administered, increase the vascular stressed volume, thereby increasing the mean systemic filling pressure (Pms) without increasing the central venous pressure (CVP). In this way, since the gradient between Pms and CVP increases, venous return-and consequently cardiac output-also increases.
In cases where physiologically ineffective fluids are administered, the situation arises in which, in addition to increasing the stressed volume and thus Pms, CVP also increases. As a result, the gradient between Pms and CVP remains unchanged, and cardiac output does not increase.
The hypothesis is that only a portion of the fluids administered during volume expansion are actually effective in increasing the gradient between Pms and CVP.
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
- Critically ill patients
Key inclusion criteria (3 listed)
- Critically ill patients admitted to the intensive care unit
- Invasive or minimally invasive hemodynamic monitoring
- Clinical indication for volume expansion with 500 mL of crystalloids
Key exclusion criteria (6 listed)
- Suspected or confirmed pregnancy
- Clinical conditions that may reduce the reliability of hemodynamic monitoring:
- Severe aortic stenosis or regurgitation
- Severe mitral stenosis or regurgitation
- History of peripheral arterial disease
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 |
|---|---|---|
| Fluid challenge of 500ml of crystalloidThe mean systemic filling pressure (Pms) will be measured using the transient stop-flow arm technique, a method routinely used in clinical practice. This involves placing a non-invasive blood pressure cuff on the same arm where invasive arterial pressure is monitored via the radial artery. The cuff is inflated for one minute to temporarily occlude blood flow. At the end of this period, the invasive arterial pressure displayed on the monitor reflects the Pms. This brief interruption of blood flow does not pose significant risks to tissue perfusion. A fluid challenge with 500 mL of crystalloids will then be performed as per clinical indication. Pms will be measured at baseline, after the infusion of 150 mL, 250 mL, 500 mL, and one hour after the end of fluid administration. Central venous pressure (CVP) and cardiac index (CI) will be continuously monitored throughout the fluid challenge. Patients will be classified as fluid responders if stroke volume (SV) increases by more than | Drug | – |
Primary outcome
Variation of the Venous Return Gradient (Pms - CVP) in Fluid Responders
Time frame: Measurements are taken at baseline, and at 7 minutes and 30 seconds, 12 minutes and 30 seconds, and 25 minutes from the start of crystalloid infusion (corresponding to 150 mL, 250 mL, and 500 mL infused, respectively).
To describe the change in the venous return gradient (mean systemic filling pressure minus central venous pressure, Pms - CVP) during volume expansion with 500 mL of crystalloids in fluid responsive patients. The fluid challenge is administered according to the clinician's indication. A total of 500 mL of crystalloids is infused over 25 minutes, corresponding to an infusion rate of 1200 mL/h.
9 secondary outcomes
Venous Return Gradient Variation in Fluid Responders vs Non-Responders
Time frame: Measurements are taken at baseline, and at 7 minutes and 30 seconds, 12 minutes and 30 seconds, and 25 minutes from the start of crystalloid infusion (corresponding to 150 mL, 250 mL, and 500 mL infused, respectively).
Venous Return Gradient Variation in the General Population
Time frame: Measurements are taken at baseline, and at 7 minutes and 30 seconds, 12 minutes and 30 seconds, and 25 minutes from the start of crystalloid infusion (corresponding to 150 mL, 250 mL, and 500 mL infused, respectively).
Cardiac Index Variation in the General Population
Time frame: Measurements are taken at baseline, and at 7 minutes and 30 seconds, 12 minutes and 30 seconds, and 25 minutes from the start of crystalloid infusion (corresponding to 150 mL, 250 mL, and 500 mL infused, respectively).
Mean Systemic Filling Pressure (Pms) Variation in the General Population
Time frame: Measurements are taken at baseline, and at 7 minutes and 30 seconds, 12 minutes and 30 seconds, and 25 minutes from the start of crystalloid infusion (corresponding to 150 mL, 250 mL, and 500 mL infused, respectively).
Central Venous Pressure (CVP) Variation in the General Population
Time frame: Measurements are taken at baseline, and at 7 minutes and 30 seconds, 12 minutes and 30 seconds, and 25 minutes from the start of crystalloid infusion (corresponding to 150 mL, 250 mL, and 500 mL infused, respectively).
Cardiac Index Variation in Fluid Responders vs Non-Responders
Time frame: Measurements are taken at baseline, and at 7 minutes and 30 seconds, 12 minutes and 30 seconds, and 25 minutes from the start of crystalloid infusion (corresponding to 150 mL, 250 mL, and 500 mL infused, respectively).
Mean Systemic Filling Pressure (Pms) Variation in Fluid Responders vs Non-Responders
Time frame: Measurements are taken at baseline, and at 7 minutes and 30 seconds, 12 minutes and 30 seconds, and 25 minutes from the start of crystalloid infusion (corresponding to 150 mL, 250 mL, and 500 mL infused, respectively).
Central Venous Pressure (CVP) Variation in Fluid Responders vs Non-Responders
Time frame: Measurements are taken at baseline, and at 7 minutes and 30 seconds, 12 minutes and 30 seconds, and 25 minutes from the start of crystalloid infusion (corresponding to 150 mL, 250 mL, and 500 mL infused, respectively).
Systemic Vascular Resistance (SVR) Variation in Fluid Responders vs Non-Responders
Time frame: Measurements are taken at baseline, and at 7 minutes and 30 seconds, 12 minutes and 30 seconds, and 25 minutes from the start of crystalloid infusion (corresponding to 150 mL, 250 mL, and 500 mL infused, respectively).
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 30 Mar 2026.
- Individual participant dataSharing planned: Undecided
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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 Hemodynamic Changes, run by Università Politecnica delle Marche at 1 site in Italy.
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 3 inclusion and 6 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 30 Mar 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 Italy. 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?
Each site lists its own contact: choose the nearest one under Trial locations. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Variation of the Venous Return Gradient (Pms - CVP) in Fluid Responders (time frame: Measurements are taken at baseline, and at 7 minutes and 30 seconds, 12 minutes and 30 seconds, and 25 minutes from the start of crystalloid infusion (corresponding to 150 mL, 250 mL, and 500 mL infused, respectively).). 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 30 Mar 2026.