Oxygen Consumption, Hypoperfusion and Organ Injury After Cardio-pulmonary Bypass (VO2-EPOC)

May 6, 2025 updated by: Julia Jakobsson, Uppsala University Hospital

Oxygen Consumption, Early Postoperative Hypoperfusion and Organ Injury After Cardio-pulmonary Bypass: a Prospective Observational Study

The goal of this observational study is to understand how oxygen consumption after heart surgery relates to blood flow problems and organ injury. The study focuses on patients over 18 years old who are having planned heart surgery with a heart-lung machine (cardiopulmonary bypass).

The main questions the study aims to answer are:

  1. How does oxygen consumption in the early hours after surgery relate to lactate levels (a sign of low oxygen supply to the tissues)?
  2. How is oxygen consumption linked to signs of poor blood flow and organ injury (such as heart, kidney, liver, brain, and gut damage)?

Researchers will measure oxygen consumption after surgery using a technique called indirect calorimetry. They will also track blood flow and oxygen use during surgery and check for signs of organ injury the day after the procedure. The study will include 65 participants. People with certain health conditions, like severe anemia, high lactate levels before surgery, or needing intensive care or extra oxygen supply before surgery, will not be included. By understanding how oxygen consumption relates to blood flow and organ injury, this research may help to better manage patients after heart surgery and reduce complications.

Study Overview

Status

Status

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

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

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.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Observational

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.
65

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Study Contact Backup

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

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Sampling Method

Non-Probability Sample

Study Population

Adult patients undergoing elective cardiac surgery at a university hospital

Description

Inclusion Criteria:

  • Elective cardiac surgery requiring cardiopulmonary bypass

Exclusion Criteria:

  • Combined, redo or annuloplasty procedures
  • Surgical procedures involving other vascular cannulation than standard direct, such as bicaval or femoral cannulation
  • Preoperative hyperlactatemia (>2mmol/L) or anaemia (Hb <90 g/dL)
  • Preoperative need for supplementary oxygen or ICU care
  • Consent not obtainable.

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

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
Difference in oxygen consumption in early postoperative hypoperfusion
Time Frame: 0-4 hours after surgery
Difference in oxygen consumption (VO2I via indirect calorimetry) in ml min-1 m-2 between patients with and without early hyperlactatemia (>2mmol/L)
0-4 hours after surgery

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
Evaluation of hypoperfusion parameters as predictors of postoperative oxygen consumption
Time Frame: 0-24 hours after surgery

Hypoperfusion parameters will be evaluated as a predictors of postoperative oxygen consumption (VO2I, ml min-1 m-2 via indirect calorimetry).

Blood gas parameters taken preoperatively and at spaced time-points up to 24 hrs after start of surgery:

1) Central venous oxygen saturation (ScvO2, %, central venous blood gas), 2) Arterial lactate (mmol/L, arterial blood gas), 3) Base excess (BE, mmol/L, arterial blood gas), 4) Venous-to-arterial CO2 difference (ΔPCO2, mmHg, arterial and central venous blood gas) and its ratio with arterial -central venous oxygen content.

Clinical variables measured hourly or otherwise specified:

5) Heart rate (beats/min), 6) Mean arterial pressure (MAP, mmHg), 7) Central venous pressure (CVP, mmHg), 8) Vasopressor or inotrope requirement (Y/N, low-intermediate-high), 9) Urine output (mL/24 hours), and 10) net fluid balance (mL/24 hours).

Additional explorative data analyses for hypothesis generating purposes can be performed.
0-24 hours after surgery
Evaluation of oxygen delivery and consumption during cardiopulmonary bypass as predictors of postoperative oxygen consumption
Time Frame: 0-4 hours during and after surgery
Oxygen delivery (DO2I, ml min-1 m-2) and oxygen consumption (VO2I ml min-1 m-2) will be measured during cardiopulmonary bypass by continuous blood parameter monitoring or calculated by blood oxygen content and pump flow. Both mean levels and repeated measures will be analysed as predictors for postoperative oxygen consumption. Additional explorative data analyses for hypothesis generating purposes can be performed.
0-4 hours during and after surgery
Evaluation of organ injury biomarkers as predictors of postoperative oxygen consumption
Time Frame: Preoperative and the day after surgery

Organ injury markers will be evaluated as predictors for postoperative oxygen consumption. Absolute levels, changes from preoperative values, and above normal predicted value (yes/no) will be used in the analysis.

Blood sampling preoperatively and the day after surgery.

  1. Renal: Creatinine (mmol L-1), Estimated glomerular filtration rate; eGFR (ml min-1 1.73 m-2):
  2. Cardiac: Troponin T; TnT, creatinine kinase-MB; CK-MB, probrain natriuretic peptide; Nt-proBNP (ng L-1)
  3. Hepatic: Aspartate aminotransferase; ASAT, alanine aminotransferase; ALAT(mikrokat L-1)
  4. Brain: Neurofilament light chain; NFL, Glial fibrillary acidic protein, GFAP (ng L-1)
  5. Gut: Medium chain fatty acids; MCFA, Short chain fatty acids; SCFA, conjugated and non-conjugated bile acids (ng ml-1) Additional explorative data analyses for hypothesis generating purposes can be performed.
Preoperative and the day after surgery

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.
Uppsala University Hospital

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Study Director: Laila Hellgren Johanssson, MD PhD Associate Professor, Unit for Cardiothoracic Surgery, Dept. of Surgical Sciences, Uppsala University

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.
May 5, 2025

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.
December 1, 2025

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.
February 1, 2026

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).
March 17, 2025

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.
April 8, 2025

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.
April 16, 2025

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.
May 11, 2025

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.
May 6, 2025

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.
May 1, 2025

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.
  • FOU2025-00095
  • 284709 (Other Identifier: Uppsala University Hospital Research Review Board)

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

UNDECIDED

IPD Plan Description

Any data will be carefully reviewed to ensure compliance with GDPR and data sharing regulations before being disclosed.

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

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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