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Cardiopulmonary Bypass SurgeryPhase 2NCT07212842

Methylene Blue-Enhanced Ultrafiltration Improves Outcomes After Cardiopulmonary Bypass

A Phase 2 study testing Methylene Blue, Conventional ultrafiltration and Zero-balance ultrafiltration in people with Cardiopulmonary Bypass Surgery and Aortic Valve Surgery, run by University of Sao Paulo at 1 site in Brazil.

Completed

Finished. The study has ended and is not enrolling. Results may be posted on the official record.

Official record
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Trial summary

Introduction: Fluid overload and systemic inflammation are major contributors to postoperative complications in patients undergoing cardiac surgery with cardiopulmonary bypass (CPB). Read more about this study

Who is it for?
Ages 20 to 60 years
What is being tested?
Methylene Blue, Conventional ultrafiltration and Zero-balance ultrafiltration
Type of treatment
Surgery or procedure
Could I receive a placebo?
Yes, some participants may receive a placebo
How many people
124 participants
Where
1 siteBrazil
Study dates
12 Apr 2021to 16 Mar 2024
Phase
Phase 2
Are there results?
None posted in the registry

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 20 to 60 years
  • All sexes
  • No healthy volunteers
  • Adult

Who may be able to join

  • Clinical diagnosis of cardiac disease requiring surgery with cardiopulmonary bypass (CPB)
  • Age ≥ 18 years
  • Ability to provide informed consent

Who cannot join

  • Chronic renal failure
  • Recent cardiac catheterization within the past month
  • Planned cardiac surgeries with an estimated CPB time of less than 60 minutes
  • Aortic surgery
  • Significantly impaired hepatic function

Trial locations and contacts

1 site in 1 country.

Brazil1 site
  • University of São Paulo Medical School in Ribeirão Preto

    Ribeirão Preto, São Paulo, 14049-900

Other trials in Brazil

About this study

Official title: METHYLENE BLUE-ENHANCED BLOOD WASHING DURING ZERO-BALANCE ULTRAFILTRATION REDUCES FLUID OVERLOAD AND INFLAMMATORY RESPONSE FOLLOWING CARDIOPULMONARY BYPASS: A RANDOMIZED CLINICAL TRIAL

Introduction: Fluid overload and systemic inflammation are major contributors to postoperative complications in patients undergoing cardiac surgery with cardiopulmonary bypass (CPB). Objective: To evaluate the effects of blood washing with methylene blue during zero-balance ultrafiltration (ZBUF) on fluid overload and systemic inflammatory response. Methodology: Fluid status was assessed using the InBody S10 precision bioimpedance device, measuring extracellular water (ECW), total body water (TBW), intracellular water (ICW), and the ECW/TBW ratio. Pulmonary congestion and intravascular volume were evaluated separately using a Philips Lumify S4-1 transducer with a Samsung tablet. Pulmonary congestion was confirmed by the presence of B-lines on lung ultrasound. Intravascular volume was assessed via the inferior vena cava (IVC) distensibility index (DI) during mechanical ventilation and collapsibility index (CI) during spontaneous breathing. Inflammatory cytokine levels were measured using a Luminex xMAP-based multiplex immunoassay.

Being tested
Methylene Blue, Conventional ultrafiltration, Zero-balance ultrafiltration
Keywords
Cardiac surgery, water overload, pulmonary congestion, intravascular volemia, cardiopulmonary bypass, zero-balance ultrafiltration, methylene blue

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

  • Methylene BlueDrug

    Also called zero-balance ultrafiltration

    This protocol was designed to perform intraoperative blood lavage with methylene blue at the end of surgery, with a duration of 20 minutes. A low dose of 1 mg/kg of body weight was administered. The objective was not to elicit hemodynamic effects, which require higher doses, but rather to exploit the anti-inflammatory and antioxidant properties of methylene blue.

    Methylene blue was diluted in 1000 mL of 0.9% saline. An equivalent volume of fluid was removed simultaneously by zero-balance ultrafiltration, maintaining a fluid-equilibrium state throughout the 20-minute procedure. For this purpose, a dedicated circuit was developed to enable concurrent blood lavage and ultrafiltration. Blood was withdrawn through a dedicated port integrated into the SORIN oxygenator and directed by a centrifugal pump to a small reservoir containing the methylene blue solution. From this reservoir, the blood passed through a hemoc

  • Conventional ultrafiltrationProcedure or surgery

    Conventional ultrafiltration (CUF). CUF during cardiopulmonary bypass (CPB) is performed to remove excess fluid and solutes from the patient's blood during cardiac surgery, thereby limiting fluid accumulation and attenuating pro-inflammatory effects. This technique increases hematocrit, improves cardiopulmonary function, and reduces the need for blood transfusions. Unlike modified ultrafiltration (MUF), which is performed after weaning from CPB, CUF is carried out simultaneously with CPB while the heart-lung machine remains in operation.

  • Zero-balance ultrafiltrationProcedure or surgery

    Zero-balance ultrafiltration (Z-BUF). Z-BUF is performed during cardiopulmonary bypass (CPB) to maintain fluid equilibrium by removing plasma water and solutes while simultaneously infusing an equal volume of replacement fluid, thereby achieving a net zero fluid balance. This technique has been shown to decrease urine output, reduce tissue edema and the inflammatory response, improve arterial oxygenation (PaO₂), and lower the need for postoperative blood transfusions.

Study groups in NCT07212842
Study groupRoleWhat they receive
Conventional ultrafiltrationActive comparatorConventional ultrafiltration (G-CUF) patients in this group underwent conventional ultrafiltration widely used in cardiac surgery with extracorporeal circulation.
Receives: Drug: Methylene Blue; Procedure: Conventional ultrafiltration; Procedure: Zero-balance ultrafiltration
Blood washing with physiological solution combined with zero-balance ultrafiltrationPlacebo comparatorBlood washing with physiological solution combined with zero-balanced ultrafiltration (G-ZBUF) patients in this group underwent zero-balanced ultrafiltration, and for this purpose, the simulation was performed with physiological solution.
Receives: Drug: Methylene Blue; Procedure: Conventional ultrafiltration; Procedure: Zero-balance ultrafiltration
Methylene blue wash combined with zero-balanced ultrafiltrationExperimentalMethylene blue lavage combined with zero-balance ultrafiltration (MB+G-ZBUF). Patients assigned to this group underwent zero-balance ultrafiltration with concomitant blood lavage using methylene blue at a low dose of 1 mg/kg of body weight. Methylene blue was diluted in 1000 mL of 0.9% saline. An equivalent volume of fluid was simultaneously removed by zero-balance ultrafiltration, ensuring a balanced fluid state throughout the 20-minute procedure. For this purpose, a dedicated circuit was developed to allow simultaneous blood lavage and ultrafiltration. Blood was withdrawn through a dedicated port integrated into the SORIN oxygenator and directed by a centrifugal pump to a small reservoir containing the methylene blue solution. From this reservoir, the blood passed through a hemoconcentrator for filtration before being returned to the central reservoir of the cardiopulmonary bypass (CPB) circuit.
Receives: Drug: Methylene Blue; Procedure: Conventional ultrafiltration; Procedure: Zero-balance ultrafiltration

What is being measured

The primary outcome is the main question the study is designed to answer.

  1. Systemic Inflammation

    To assess systemic inflammation, blood samples were collected via central venous access through the internal jugular vein at five time points: before surgery, during surgery, 10 minutes after cannulation, 10 minutes after blood lavage with methylene blue and ultrafiltration, and 4 hours after ICU admission. Samples were drawn into EDTA-containing syringes (50 mM, pH 8.0) at one-tenth of the total blood volume. Plasma was separated by centrifugation at 1,700 × g for 10 minutes at 4 °C, transferred to new tubes avoiding the buffy coat, and centrifuged again at 11,000 × g for 2 minutes at 4 °C. Plasma was aliquoted and stored at -80 °C. Cytokine concentrations were quantified using a Luminex xMAP multiplex immunoassay (8-27-plex) in triplicate, enabling simultaneous measurement of up to seven cytokines, chemokines, and interleukins from 50 μL plasma.

    Measured: Three years

  2. Water overload

    Fluid balance was meticulously monitored, including fluids removed by conventional ultrafiltration, surgical suction, sponges, and urine output. Discrepancies between infused and removed volumes were corrected using zero-balance ultrafiltration (ZBUF), removing excess fluid or compensating deficits to match preoperative volemic status. For example, if 100 mL more than planned had been removed, only 900 mL were withdrawn. Body fluid composition was assessed with the InBody S10 bioimpedance device. Extracellular water (ECW) was measured at 5 kHz, total body water (TBW) at 250 kHz, and intracellular water (ICW) calculated as TBW-ECW. The ECW/TBW ratio served as the primary parameter to monitor fluid status and detect overload.

    Measured: Three years

  3. Intravascular volume assessment using IVC indices

    Intravascular volume will be evaluated by analyzing mechanical and hemodynamic changes in the inferior vena cava (IVC) using subcostal ultrasound images. The collapsibility index (CI = (IVCmax - IVCmin)/IVCmax) will be used during spontaneous breathing, and the distensibility index (DI = (IVCmax - IVCmin)/IVCmin) during mechanical ventilation.

    Time Frame: Preoperatively, immediately postoperatively, and 24 hours after surgery.

    Unit of Measure: Percentage (%).

    Measured: Three years

Secondary outcomes (1)
  1. Length of stay in the intensive care unit (ICU)

    Secondary outcomes included the length of stay in the intensive care unit (ICU), measured in hours, to evaluate the clinical impact of zero-balance ultrafiltration with methylene blue. This parameter was recorded for all patients and analyzed in relation to fluid balance, pulmonary congestion, intravascular volume, and systemic inflammatory markers, providing a comprehensive assessment of the intervention's effects on postoperative recovery.

    Measured: Three years

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

  1. First posted8 Oct 2025
  2. Study start12 Apr 2021
  3. Primary completion25 Aug 2023
  4. Study completion16 Mar 2024

Resources

More details

For doctors and researchers: how the study is designed, who runs it, and its registry IDs.

Study design
Study type
Interventional
Phase
Phase 2
Primary purpose
Treatment
Allocation
Randomised
Intervention model
Parallel groups
Model description
The objective of this study was to evaluate the effects of methylene blue blood lavage during zero-balance ultrafiltration (ZBUF) on fluid overload and the systemic inflammatory response. Patients were randomly assigned to one of three groups: conventional ultrafiltration (G-CUF; n = 43), saline blood lavage combined with ZBUF (G-ZBUF; n = 39), and methylene blue lavage combined with ZBUF (MB+G-ZBUF; n = 42). Fluid status was assessed using the InBody S10 precision bioimpedance device, which measured extracellular water (ECW), total body water (TBW), intracellular water (ICW), and the ECW/TBW ratio. Pulmonary congestion and intravascular volume were assessed separately with a Philips Lumify S4-1 transducer connected to a Samsung tablet. Pulmonary congestion was defined by the presence of B-lines on lung ultrasound. Intravascular volume was assessed using the inferior vena cava (IVC) distensibility index (DI) during mechanical ventilation and the collapsibility index (CI) during spontan
Masking
Single blind
Who is masked
Participant
Enrolment
124 participants (actual)
IDs, dates and publications
ClinicalTrials.gov ID
NCT07212842
Sponsor's protocol ID
2.462.520
Status last verified
Sep 2025
First submitted
23 Sep 2025
Last updated
8 Oct 2025
Results posted
No
FDA-regulated drug
No
FDA-regulated device
No
Individual data sharing
No

Questions about this trial

What is this clinical trial studying?

A Phase 2 study testing Methylene Blue, Conventional ultrafiltration and Zero-balance ultrafiltration in people with Cardiopulmonary Bypass Surgery and Aortic Valve Surgery, run by University of Sao Paulo at 1 site in Brazil.

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 5 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: finished, as of the sponsor's last update on 8 Oct 2025. 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 Brazil. 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. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.

What does this phase mean?

Phase 2 studies give the treatment to a larger group to see whether it has the intended effect and to keep checking safety.

Not every study follows the same path, and some studies (observational studies, device studies) have no phase.

Are results available for this study?

The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.

How can a doctor refer a patient or contact the research team?

The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

Systemic Inflammation (time frame: Three years). The study lists 3 primary outcomes in all. 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 8 Oct 2025.

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