Methylene Blue-Enhanced Ultrafiltration Improves Outcomes After Cardiopulmonary Bypass
- Conditions
- Cardiopulmonary Bypass SurgeryAortic Valve SurgeryMitral Valve SurgeryMyocardial Revascularization Surgery With Extracorporeal Circulation
- Interventions
- Registration Number
- NCT07212842
- Lead Sponsor
- University of Sao Paulo
- Brief Summary
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.
- Detailed Description
Not available
Recruitment & Eligibility
- Status
- COMPLETED
- Sex
- All
- Target Recruitment
- 124
Clinical diagnosis of cardiac disease requiring surgery with cardiopulmonary bypass (CPB)
Age ≥ 18 years
Ability to provide informed consent
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
Study & Design
- Study Type
- INTERVENTIONAL
- Study Design
- PARALLEL
- Arm && Interventions
Group Intervention Description Conventional ultrafiltration Methylene Blue Conventional ultrafiltration (G-CUF) patients in this group underwent conventional ultrafiltration widely used in cardiac surgery with extracorporeal circulation. Conventional ultrafiltration Conventional ultrafiltration Conventional ultrafiltration (G-CUF) patients in this group underwent conventional ultrafiltration widely used in cardiac surgery with extracorporeal circulation. Conventional ultrafiltration Zero-balance ultrafiltration Conventional ultrafiltration (G-CUF) patients in this group underwent conventional ultrafiltration widely used in cardiac surgery with extracorporeal circulation. Blood washing with physiological solution combined with zero-balance ultrafiltration Methylene Blue Blood 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. Blood washing with physiological solution combined with zero-balance ultrafiltration Conventional ultrafiltration Blood 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. Blood washing with physiological solution combined with zero-balance ultrafiltration Zero-balance ultrafiltration Blood 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. Methylene blue wash combined with zero-balanced ultrafiltration Methylene Blue Methylene 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. Methylene blue wash combined with zero-balanced ultrafiltration Conventional ultrafiltration Methylene 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. Methylene blue wash combined with zero-balanced ultrafiltration Zero-balance ultrafiltration Methylene 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.
- Primary Outcome Measures
Name Time Method Systemic Inflammation Three years 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.
Water overload Three years 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.
Intravascular volume assessment using IVC indices Three years 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 (%).
- Secondary Outcome Measures
Name Time Method Length of stay in the intensive care unit (ICU) Three years 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.
Trial Locations
- Locations (1)
University of São Paulo Medical School in Ribeirão Preto
🇧🇷Ribeirão Preto, São Paulo, Brazil
University of São Paulo Medical School in Ribeirão Preto🇧🇷Ribeirão Preto, São Paulo, Brazil