Measuring how a 500 mL IV fluid bolus changes venous return to the heart
Assessment of Venous Return During Volume Expansion: a Prospective Observational Study
This test tries to see if giving 500 mL of crystalloid raises the pressure that drives blood back to the heart and increases cardiac output in critically ill ICU patients who need a fluid bolus.
Quick facts
| Study type | Observational |
|---|---|
| Enrollment | 45 (estimated) |
| Ages | 18 Years and up |
| Sex | All |
| Sponsor | Università Politecnica delle Marche Academic / other |
| Locations | 1 site (Ancona) |
| Trial ID | NCT07499388 on ClinicalTrials.gov |
What this trial studies
This prospective observational study enrolls critically ill patients in the intensive care unit who have invasive or minimally invasive hemodynamic monitoring and a clinical indication for a 500 mL crystalloid volume expansion. Investigators will give a 500 mL crystalloid fluid challenge and measure changes in mean systemic filling pressure (Pms), central venous pressure (CVP), and the gradient between them to determine whether venous return—and therefore cardiac output—actually increases. The protocol excludes patients with conditions that reduce monitoring reliability (severe valvular disease, peripheral arterial disease), pregnancy, or contraindication to the supine position. The work is conducted at AOU delle Marche (Ancona) under the sponsorship of Università Politecnica delle Marche.
Who should consider this trial
Good fit: Ideal candidates are critically ill ICU patients who have invasive or minimally invasive hemodynamic monitoring and a clinical indication for a 500 mL crystalloid bolus, and who do not meet exclusion criteria such as pregnancy or severe valvular disease.
Not a fit: Patients without hemodynamic monitoring, those with excluded conditions (pregnancy, severe aortic or mitral valve disease, peripheral arterial disease), or those who cannot be positioned supine are unlikely to benefit from participating.
Why it matters
Potential benefit: If successful, this could help clinicians give fluids more precisely by identifying when a bolus will actually increase blood return and cardiac output, potentially avoiding unnecessary fluid overload.
How similar studies have performed: Prior research has widely studied fluid responsiveness using cardiac output changes, but applying Guyton-derived Pms measurements during a fluid bolus is relatively novel and has limited prior direct evidence.
Eligibility criteria
Show full inclusion / exclusion criteria
Inclusion Criteria: * 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 Exclusion Criteria: * 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
Where this trial is running
Ancona
- AOU delle Marche — Ancona, Italy (Recruiting)
How to participate
- Review the eligibility criteria above with your treating physician.
- Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
- Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.