Evaluation of the Microcirculatory Response to Fluids in Critically Ill Patients With Venous Congestion: A Prospective Observational Study

Status

Recruiting

Phases

Unknown

Study type

Observational

Source

ClinicalTrials.gov

Registry ID

NCT07499401

Acronym

MICRO-CONGEST

Enrollment

Registered

2026-03-30

Start date

2024-12-15

Completion date

2026-06-01

Last updated

2026-04-02

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Microcirculation, Venous Congestion, Volume Expansion

Brief summary

The hypothesis is that fluid-responsive patients who show signs of venous congestion experience a worsening of microcirculatory status after fluid administration compared to patients without signs of venous congestion

Interventions

DRUGfluid challenge

Signs of venous congestion and microcirculatory status will be assessed at baseline. A fluid challenge will then be performed, and microcirculation will be evaluated at the end of fluid administration and again after 30 minutes

Study design

Observational model

COHORT

Time perspective

PROSPECTIVE

Eligibility

Sex/Gender

ALL

Age

18 Years to No maximum

Healthy volunteers

Inclusion criteria

* Critically ill patients admitted to the intensive care unit * Invasive or minimally invasive hemodynamic monitoring

Exclusion criteria

* Suspected or confirmed pregnancy * Inability to access the oral cavity (e.g., facial trauma, oral bleeding)

Design outcomes

Primary

Measure	Time frame	Description
Change in Sublingual total vessel density (TVD)	Baseline, immediately post-fluid challenge, and 30 minutes post-fluid challenge	To compare changes in sublingual microcirculatory parameter - total vessel density (TVD) - before fluid administration, immediately after volume expansion, and 30 minutes post-fluid administration in preload-dependent patients with and without signs of venous congestion.

Secondary

Measure	Time frame	Description
Change in Sublingual percentage of perfused vessels (PPV)	Baseline, immediately post-fluid challenge, and 30 minutes post-fluid challenge	To compare changes in sublingual microcirculatory parameter - percentage of perfused vessels (PPV) - before fluid administration, immediately after volume expansion, and 30 minutes post-fluid administration in preload-dependent patients with and without signs of venous congestion.
Change in Sublingual Microcirculatory Flow Index (MFI)	Baseline, immediately post-fluid challenge, and 30 minutes post-fluid challenge	The primary objective of the study is to compare changes in sublingual microcirculation, measured by the Microcirculatory Flow Index (MFI), before fluid administration, immediately after volume expansion, and 30 minutes post-fluid administration in preload-dependent patients with and without signs of venous congestion.
Change in Sublingual perfused vessel density (PVD)	Baseline, immediately post-fluid challenge, and 30 minutes post-fluid challenge	To compare changes in sublingual microcirculatory parameters - perfused vessel density (PVD) - before fluid administration, immediately after volume expansion, and 30 minutes post-fluid administration in preload-dependent patients with and without signs of venous congestion.
Change in Sublingual microcirculatory heterogeneity index (MHI)	Baseline, immediately post-fluid challenge, and 30 minutes post-fluid challenge	To compare changes in sublingual microcirculatory parameters - microcirculatory heterogeneity index (MHI) - before fluid administration, immediately after volume expansion, and 30 minutes post-fluid administration in preload-dependent patients with and without signs of venous congestion.
Change in Sublingual PPV in Non-Preload-Dependent Patients With and Without Venous Congestion	Baseline, immediately post-fluid challenge, and 30 minutes post-fluid challenge	To compare changes in sublingual PPV before fluid administration, immediately after volume expansion, and 30 minutes post-fluid administration in non-preload-dependent patients with and without signs of venous congestion.
Change in Sublingual TVD in Non-Preload-Dependent Patients With and Without Venous Congestion	Baseline, immediately post-fluid challenge, and 30 minutes post-fluid challenge	To compare changes in sublingual TVD before fluid administration, immediately after volume expansion, and 30 minutes post-fluid administration in non-preload-dependent patients with and without signs of venous congestion.
Change in Sublingual MFI in Non-Preload-Dependent Patients With and Without Venous Congestion	Baseline, immediately post-fluid challenge, and 30 minutes post-fluid challenge	To compare changes in sublingual MFI before fluid administration, immediately after volume expansion, and 30 minutes post-fluid administration in non-preload-dependent patients with and without signs of venous congestion.
Change in Sublingual PVD in Non-Preload-Dependent Patients With and Without Venous Congestion	Baseline, immediately post-fluid challenge, and 30 minutes post-fluid challenge	To compare changes in sublingual PVD before fluid administration, immediately after volume expansion, and 30 minutes post-fluid administration in non-preload-dependent patients with and without signs of venous congestion.
Change in Sublingual MHI in Non-Preload-Dependent Patients With and Without Venous Congestion	Baseline, immediately post-fluid challenge, and 30 minutes post-fluid challenge	To compare changes in sublingual MHI before fluid administration, immediately after volume expansion, and 30 minutes post-fluid administration in non-preload-dependent patients with and without signs of venous congestion.
Association Between Venous Congestion and TVD in Critically Ill Patients and Subpopulations	Baseline, immediately post-fluid challenge, and 30 minutes post-fluid challenge	o evaluate the relationship between signs of venous congestion TVD at baseline, after fluid administration, and 30 minutes post-fluid administration in critically ill patients and subgroups (e.g., septic shock).
Association Between Venous Congestion and PVD in Critically Ill Patients and Subpopulations	Baseline, immediately post-fluid challenge, and 30 minutes post-fluid challenge	To evaluate the relationship between signs of venous congestion and PVD at baseline, after fluid administration, and 30 minutes post-fluid administration in critically ill patients and subgroups (e.g., septic shock).
Association Between Venous Congestion and MFI in Critically Ill Patients and Subpopulations	Baseline, immediately post-fluid challenge, and 30 minutes post-fluid challenge	To evaluate the relationship between signs of venous congestion and MFI at baseline, after fluid administration, and 30 minutes post-fluid administration in critically ill patients and subgroups (e.g., septic shock).
Association Between Venous Congestion and PPV in Critically Ill Patients and Subpopulations	Baseline, immediately post-fluid challenge, and 30 minutes post-fluid challenge	To evaluate the relationship between signs of venous congestion and PPV at baseline, after fluid administration, and 30 minutes post-fluid administration in critically ill patients and subgroups (e.g., septic shock).
Association Between Venous Congestion and MHI in Critically Ill Patients and Subpopulations	Baseline, immediately post-fluid challenge, and 30 minutes post-fluid challenge	To evaluate the relationship between signs of venous congestion and MHI at baseline, after fluid administration, and 30 minutes post-fluid administration in critically ill patients and subgroups (e.g., septic shock).
Association Between Venous Congestion and TVD at Baseline	Baseline	To evaluate the association between signs of venous congestion and TVD at baseline in critically ill patients and subgroups (e.g., septic shock).
Association Between Venous Congestion and PVD at Baseline	Baseline	To evaluate the association between signs of venous congestion and PVD at baseline in critically ill patients and subgroups (e.g., septic shock).
Association Between Venous Congestion and MFI at Baseline	Baseline	To evaluate the association between signs of venous congestion and MFI at baseline in critically ill patients and subgroups (e.g., septic shock).
Association Between Venous Congestion and PPV at Baseline	Baseline	To evaluate the association between signs of venous congestion and PPV at baseline in critically ill patients and subgroups (e.g., septic shock).
Association Between Venous Congestion and MHI at Baseline	Baseline	To evaluate the association between signs of venous congestion and MHI at baseline in critically ill patients and subgroups (e.g., septic shock).

Countries

Italy

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: Apr 3, 2026