Assessment of Blood Viscosity in ARDS (Acute Respiratory Distress Syndrome)

NCT07823296 — Not yet recruiting, 46 participants, Hospices Civils de Lyon

ClinicalTrials Daily · Areas · Conditions · Drugs · Sponsors ·

Assessment of Blood Viscosity in ARDS

Registry	NCT07823296, acronym VISC-ARDS
Status	Not yet recruiting
Study type	Observational
Enrollment	46 (Estimated)
Sponsor	Hospices Civils de Lyon (Other)
Conditions	ARDS
Interventions	Blood draws (peripheral venous puncture), Blood draws (arterial catheter, central venous line, or Swan-Ganz catheter) (Biological, other)
Dates	start 2026-10-01 (estimated), primary completion 2028-01-01 (estimated), completion 2028-01-01 (estimated), first posted 2026-09-16, last updated 2026-09-16
Locations	1 site in France

-Summary

Acute respiratory distress syndrome (ARDS) is characterized by damage to the alveolar-capillary membrane, resulting in hypoxemia, decreased pulmonary compliance, and hemodynamic changes.

Critical conditions (hypoxia; septic shock associated with ARDS) can alter blood viscosity. These changes in viscosity can affect blood flow and hemodynamics.

There is only one clinical study that has measured one of the determinants of blood viscosity in ARDS (deformability), even though other parameters are involved in viscosity (elongation, deformability, hematocrit, etc.), and it is possible to measure blood viscosity comprehensively. To date, therefore, no study has evaluated the various parameters of blood viscosity in ARDS.

The aim of this study is to investigate hyperviscosity in patients with ARDS and to assess whether this hyperviscosity correlates with respiratory or hemodynamic changes.

The investigators will therefore compare blood viscosity and its determinants in patients admitted to the intensive care unit for ARDS and in patients admitted for other reasons (excluding ARDS or sepsis/septic shock).

The investigators will also conduct a longitudinal assessment of changes in hemodynamic, respiratory, and viscosity parameters during ARDS

Expand all sections · Collapse all

+Arms and interventions

Arm	Type	Interventions	Description
Case group		Biological: Blood draws (peripheral venous puncture); Other: Blood draws (arterial catheter, central venous line, or Swan-Ganz catheter)	Patients over 18 years of age with moderate to severe ARDS (overall definition) (P/F <200)
Control group		Biological: Blood draws (peripheral venous puncture)	Patients admitted to intensive care unit without ARDS or sepsis/septic shock

Blood draws (peripheral venous puncture) (Biological): Procedure performed by intensive care nurses. Case group : Daily blood draws (4 mL) for 7 days. Control group : blood draws (4 mL) on Day 1.
Blood draws (arterial catheter, central venous line, or Swan-Ganz catheter) (Other): Case group : For patients with an arterial catheter, central venous line, or Swan-Ganz catheter, an additional blood sample will be collected on Day 1.

+Outcome measures

Primary outcomes

Comparison of Blood Viscosity in Patients with ARDS and Control Group on Day 1 [At day 1]: Blood viscosity will be determined after complete oxygenation of the blood, at native hematocrit, at a temperature of 25 °C. Measurements will be performed at different shear rates (11.5, 22.5, 45, 90, and 225 s-¹) using a cone-plate viscometer (Brookfield DVII+ equipped with a CPE40 cone, Brookfield Engineering Labs, Natick, MA, USA). This technique is based on applying a well-defined shear rate gradient between a moving conical surface and a fixed flat surface, with the blood sample placed between them. The fluid subjected to this shear resists flow in proportion to its viscosity. The higher the viscosity, the greater the torque required to maintain motion. This approach allows for the precise measurement of the apparent viscosity of blood across a wide range of mechanical stresses, replicating the flow conditions encountered in the bloodstream. The value at 225 s-¹ will be used as the primary endpoint (with an accuracy of 5-10 centipoise at this shear rate).

+Eligibility

Sex: All, ages: 18 Years to any

Case Group

Inclusion Criteria:

* Age ≥ 18 ans
* Moderate-to-severe ARDS according to the global definition:
* with PaO₂/FiO₂ ≤ 200 mmHg (based on arterial blood gas analysis in patients receiving invasive or non-invasive mechanical ventilation or high-flow nasal oxygen therapy).
* Participation agreement obtained (either from the patient themselves or from a relative)

Exclusion Criteria:

* ARDS that has been present for more than 72 hours
* Terminally ill patient with death expected within 24 hours
* Patient who has received a blood transfusion within the past month
* Patient with a known hematologic malignancy (lymphoma; myeloma; acute or chronic leukemia)
* Patient with a known hemoglobinopathy.
* Hemorrhagic shock
* Hemoglobin < 70 g/dL

Control group

Inclusion Criteria:

* Age ≥ 18 ans
* Participation agreement obtained (either from the patient themselves or from a relative)

Exclusion Criteria:

* Presence of ARDS according to the global definition
* P/F < 300 mmHg
* Presence of sepsis defined by an infection and a SOFA score delta ≥ 2.
* Terminally ill patient with death expected within 24 hours
* Patient who has received a blood transfusion within the past month
* Patient with a known hematologic malignancy (lymphoma; myeloma; acute or chronic leukemia)
* Patient with a known hemoglobinopathy.
* Hemorrhagic shock
* Hemoglobin < 70 g/dL

+Locations (1)

Facility	City	Country	Status
Hopital de la Croix-Rousse	Lyon	France