Optimized Cardiopulmonary Bypass Flow Strategy Based on Ideal Body Weight in Obese Patients Undergoing Cardiac Surgery (IDEALFLOW)

October 29, 2026 updated by: Centre Hospitalier Universitaire, Amiens

Cardiopulmonary bypass (CPB) pump flow is typically calculated according to body surface area (BSA) derived from actual body weight and temperature, following the 2024 European guidelines recommending an indexed flow of 2.4 L/min/m². However, in obese patients, using actual weight leads to a high BSA and thus elevated pump flow, increasing technical challenges such as the need for larger cannulas, higher circulating blood volume, and elevated pump speeds. These adjustments may increase risks of hemodilution, transfusion, and hemolysis. Given that lean body mass in obese patients is similar to that of non-obese patients of the same height-and that aerobic metabolism depends on lean mass-adjusting CPB flow based on ideal body weight rather than actual weight could reduce transfusions and associated complications. Several observational studies support the concept of using ideal body weight for CPB flow calculation in obese patients. Despite this, no randomized controlled trial has yet addressed the clinical impact of this approach. Given the increasing prevalence of obesity and the practical challenges it poses during cardiac surgery, a controlled clinical trial is warranted.

The investigators hypothesize that adjusting the cardiopulmonary bypass (CPB) flow according to the ideal body weight rather than the actual body weight in obese patients could reduce the need for blood transfusions and limit the associated complications.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Recruiting

Conditions

Conditions

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Intervention / Treatment

Intervention / Treatment

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Study Type

Study Type

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Interventional

Enrollment (Estimated)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
184

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Not Applicable

Contacts and Locations

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Study Contact

Study Contact

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Study Locations

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

18 years and older (Adult, Older Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Description

Inclusion Criteria:

  • Patients aged over 18 years
  • Patients with obesity (BMI > 30 kg/m²)
  • Scheduled cardiac surgery under cardiopulmonary bypass (CPB):
  • Coronary artery bypass grafting (CABG)
  • Aortic valve replacement
  • Mitral valve repair or replacement
  • Surgery on the aortic root (aortic tube, Bentall procedure, Tirone David, or others)
  • Combined surgery
  • Affiliation to a social security scheme
  • Written informed consent

Exclusion Criteria:

  • Minors
  • BMI < 30 kg/m²
  • Off-pump cardiac surgery
  • Surgery on the aortic arch
  • Planned perioperative hypothermia < 32ºC
  • Emergency surgery
  • Heart transplantation or mechanical circulatory support surgery
  • Infectious endocarditis
  • Participation in another clinical trial within the past 30 days
  • Pregnant, parturient, or breastfeeding women
  • Patients under guardianship, curatorship, or deprived of civil rights
  • Advanced chronic kidney disease (renal clearance < 30 ml/min)
  • Coexisting disease with a high probability of death within 6 months
  • Preoperative anemia (hemoglobin < 10 g/dL)
  • Body surface area (actual body weight) > 2.5 m²

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Other
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Single

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: body surface area (BSA) calculated from ideal body weight

Cardiac surgery under cardiopulmonary bypass (CPB) with CPB flow indexed at 2.4 ml/min/m², using body surface area (BSA) calculated from ideal body weight (Lorentz formula)
Procedure: cardiopulmonary bypas

CPB is standardized according to the following protocol:

  • Cardiac index at 2.4 ml/min/m²
  • Mean arterial pressure during CPB between 50 and 80 mm Hg
  • Central venous oxygen saturation > 65%
  • Hematocrit > 25%
  • DO₂ > 280 ml/min/m²
  • VCO₂/DO₂ > 6 (VCO₂: CO₂ production) CPB will be performed under normothermia, with a temperature > 36°C.
Other: Anticoagulation

Anticoagulation will be managed according to center practices to maintain an activated clotting time (ACT) > 400 seconds, in accordance with recommendations.
Active Comparator: BSA calculated from actual body weight.

Cardiac surgery under CPB with CPB flow indexed at 2.4 ml/min/m², using BSA calculated from actual body weight.
Procedure: cardiopulmonary bypas

CPB is standardized according to the following protocol:

  • Cardiac index at 2.4 ml/min/m²
  • Mean arterial pressure during CPB between 50 and 80 mm Hg
  • Central venous oxygen saturation > 65%
  • Hematocrit > 25%
  • DO₂ > 280 ml/min/m²
  • VCO₂/DO₂ > 6 (VCO₂: CO₂ production) CPB will be performed under normothermia, with a temperature > 36°C.
Other: Anticoagulation

Anticoagulation will be managed according to center practices to maintain an activated clotting time (ACT) > 400 seconds, in accordance with recommendations.

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
reduction in the incidence of erythrocyte concentrates transfused
Time Frame: 1 day

reduction in the incidence of erythrocyte concentrates transfused from the start to the end of cardiopulmonary bypass (CPB)
1 day

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
hematocrit measurement during CPB
Time Frame: 1 day

Hemodilution quantified by hematocrit measurement during CPB
1 day
Number of platelet concentrates administered during CPB
Time Frame: 1 day

Number of platelet concentrates administered during CPB
1 day
Number of fresh frozen plasma units administered during CPB
Time Frame: 1 day

Number of fresh frozen plasma units administered during CPB
1 day
Number of labile blood products administered during the entire ICU stay
Time Frame: 1 day

Number of labile blood products administered during the entire ICU stay
1 day
Number of Acute kidney injury
Time Frame: within 7 days

Acute kidney injury defined according to KDIGO criteria by an increase in serum creatinine ≥26.5 μmol/L or at least 1.5 times the baseline value within 7 days after surgery compared to the preoperative baseline
within 7 days

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Centre Hospitalier Universitaire, Amiens

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
September 21, 2026

Primary Completion (Estimated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
September 1, 2029

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
September 1, 2029

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
October 29, 2026

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
October 29, 2026

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
November 4, 2026

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
November 4, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
October 29, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
October 1, 2026

More Information

Terms related to this study

Keywords

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • PI2026_843_0111

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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