An observational study in Cardiac Surgery Requiring Cardiopulmonary Bypass, sponsored by Uppsala University Hospital. Recruiting at 1 site in Sweden. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2025-05-11.
Sponsored by Uppsala University Hospital · Observational
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:
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.
Uppsala University Hospital is the lead sponsor of 73 studies on the registry; 19 are open to participants now.
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Adult patients undergoing elective cardiac surgery at a university hospital
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Exclusion Criteria:
After arrival to the ICU, prior to cessation of iv anaesthetics and extubation, indirect calorimetry will be performed by connecting a metabolic monitor to the ventilator during a minimum of 20 minutes.
Difference in oxygen consumption in early postoperative hypoperfusion
Difference in oxygen consumption (VO2I via indirect calorimetry) in ml min-1 m-2 between patients with and without early hyperlactatemia (\>2mmol/L)
Time frame: 0-4 hours after surgery
Evaluation of hypoperfusion parameters as predictors of postoperative oxygen consumption
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.
Time frame: 0-24 hours after surgery
Evaluation of oxygen delivery and consumption during cardiopulmonary bypass as predictors of postoperative oxygen consumption
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.
Time frame: 0-4 hours during and after surgery
Evaluation of organ injury biomarkers as predictors of postoperative oxygen consumption
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.
Time frame: Preoperative and the day after surgery
Plan to share: Undecided — Any data will be carefully reviewed to ensure compliance with GDPR and data sharing regulations before being disclosed.
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Uppsala University Hospital