Study on the Relationship of Arterial-venous Oxygen Difference and Postoperative Complications After Cardiac Surgery.

Avoidance of unnecessary blood transfusions has always been a focus of clinical research. The rate of perioperative red blood cell transfusion in patients undergoing cardiac surgery under cardiopulmonary bypass reaches between 50-70%, and the intraoperative red blood cell transfusion rate is 30-50%. Regarding whether and when to perform a blood transfusion, it is necessary to comprehensively consider the benefits and risks brought by blood transfusion.

Previous studies on blood transfusion strategies have mainly focused on the hemoglobin threshold, but the hemoglobin level does not fully reflect the level of tissue oxygenation. Mixed venous blood oxygen saturation has been widely studied as a valuable indicator reflecting the balance of oxygen delivery and oxygen consumption. But due to the difficulty of placing a pulmonary artery floating catheter for monitoring, its clinical application is limited. Central venous oxygen saturation requires only a small collection of blood samples, which can reflect the oxygen saturation of the superior vena cava, and studies have shown that it can effectively guide the blood transfusion of patients undergoing cardiac surgery. Existing studies have shown that in critically ill patients, the use of arterial-venous oxygen difference > 3.7 mL as an indicator to guide blood transfusion can lead to a higher 90-day survival rate. However, the relationship between the arterial-venous oxygen difference and the incidence of adverse events in cardiac surgery patients under CPB remains unclear. Whether increasing the arterial-venous oxygen difference during surgery can reduce the incidence of postoperative adverse events remains to be clarified.

This study intends to collect intraoperative arterial blood and central venous blood samples from cardiac surgery patients undergoing CPB, and analyze the relationship between arterial-venous oxygen difference and the incidence of postoperative adverse events.

Study Overview

• Status: Completed
• Conditions: Cardiac Surgery; Transfusion; Patient Blood Management
• Intervention / Treatment: Other: No intervention

Detailed Description

The >18 y/o patients who undergo cardiac surgery with cardiopulmonary bypass and with a preoperative additive EuroSCORE I≥ 6 are enrolled. Blood samples will be collected through arteries and central venous at the following intraoperative time points: before CPB, during CPB, and after CPB. The observation will end by hospital discharge or 28 days after surgery, whichever came first. The follow-up will continue for one year after surgery.

• Study Type: Observational
• Enrollment (Actual): 314

Contacts and Locations

Study Locations

• China
  • Zhejiang
    • Hangzhou, Zhejiang, China, 310000
      • The Second Affiliated Hospital of Zhejiang University anesthesiology department

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No

• Sampling Method: Non-Probability Sample

Study Population

Moderate to high risk patients undergoing cardiac surgery with cardiopulmonary bypass (CPB)

Description

Inclusion Criteria:

• Over 18 years old
• Cardiovascular surgery patients with cardiopulmonary bypass
• Preoperative EuroSCORE I≥6（European System for Cardiac Operative Risk Evaluation)
• Obtained informed consent

Exclusion Criteria:

• Patients who cannot accept blood products
• Patients who refuse to accept transfusion
• Patients with autologous blood reserve before surgery
• Patients who are going to receive heart transplantation or have undergone heart transplantation
• Patients who have undergone ventricular assist device implantation surgery
• Patients who refuse to participate in this trial

Study Plan

How is the study designed?

Number of groups / cohorts

1

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
Patients undergoing cardiac surgery with CPB; >18 y/o patients who undergo cardiac surgery with cardiopulmonary bypass and with a preoperative additive EuroSCORE I≥ 6	Other: No intervention; No intervention

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Composite outcome of mortality and serious morbidity (cardiac, renal, and neurological events)	Composite incidence of any one of the following events occurring during the hospitalization : (1) all-cause mortality; (2) myocardial infarction; (3) new renal failure requiring dialysis; or (4) new focal neurological deficit (stroke)	From the start of surgery until hospital discharge or postoperative day 28, whichever comes first

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Incidence of any independent component of the primary outcome	Incidence of any independent component of the primary outcome (all-cause mortality, myocardial infarction, new renal failure requiring dialysis, and new focal neurological deficit (stroke))	From the start of surgery until hospital discharge or postoperative day 28, whichever comes first
Blood product transfusion	Time, category, and volume of blood product transfusion	From the start of surgery until hospital discharge or postoperative day 28, whichever comes first
Length of stay in ICU	Length of stay in ICU after surgery	From the start of surgery until hospital discharge or postoperative day 28, whichever comes first
Total length of hospital stay after surgery	Total length of hospital stay after surgery	From the start of surgery until hospital discharge or postoperative day 28, whichever comes first
Duration of mechanical ventilation after surgery	Total length of hospital stay after surgery	From the start of surgery until hospital discharge or postoperative day 28, whichever comes first
Occurrence of low cardiac output after surgery	Need for two or more inotropes for 24 hours or more, intra-aortic balloon pump postoperatively or ventricular assist device	From the start of surgery until hospital discharge or postoperative day 28, whichever comes first
Infection	Infection will be defined as septic shock with positive blood cultures; pneumonia defined as autopsy diagnosis or roentgenographic infiltrate and at least two of the following three criteria: fever, leukocytosis, and positive sputum culture; and/or deep sternal or leg wound infection requiring intravenous antibiotics and/or surgical debridement	From the start of surgery until hospital discharge or postoperative day 28, whichever comes first
Gut infarction	confirmed by imaging, autopsy, or through surgical means	From the start of surgery until hospital discharge or postoperative day 28, whichever comes first
Acute kidney injury	AKI defined by the KDIGO	From the start of surgery until hospital discharge or postoperative day 28, whichever comes first
Seizures	Defined as generalized or focal tonic-clonic movements consistent with seizure; or EEG demonstrating epileptiform discharges; or diagnosis of seizures by neurologist or neurosurgeon consultation	From the start of surgery until hospital discharge or postoperative day 28, whichever comes first
Delirium	Based on one of the following criteria: CAM-ICU/ CAM (even on 1 occasion) or ICDSC > 3 or more than one dose of haloperidol or similar antipsychotic drug or documented delirium by neurologist or neurosurgeon or psychiatrist consultation	From the start of surgery until hospital discharge or postoperative day 28, whichever comes first
Encephalopathy	Defined as unexpected delayed awakening or severely altered mental status (unconscious despite no sedative medication for more than 5 days), or encephalopathy documented by neurologist or neurosurgeon or psychiatrist consultation	From the start of surgery until hospital discharge or postoperative day 28, whichever comes first
Reoperation rate	The rate of reoperation	From the start of surgery until hospital discharge or postoperative day 28, whichever comes first

Collaborators and Investigators

• Sponsor: Second Affiliated Hospital, School of Medicine, Zhejiang University
• Investigators: Principal Investigator: Min Yan, Doctor, 2nd Affiliated Hospital, School of Medicine, Zhejiang University, China

Study record dates

Study Major Dates

• Study Start (Actual): October 18, 2021
• Primary Completion (Actual): May 30, 2023
• Study Completion (Actual): May 30, 2023

Study Registration Dates

• First Submitted: September 27, 2021
• First Submitted That Met QC Criteria: October 13, 2021
• First Posted (Actual): October 14, 2021

Study Record Updates

• Last Update Posted (Actual): March 25, 2025
• Last Update Submitted That Met QC Criteria: January 24, 2025
• Last Verified: January 1, 2025

More Information

Terms related to this study

• Keywords: Patient blood management; arterial-venous oxygen difference
• Additional Relevant MeSH Terms: Pathologic Processes; Postoperative Complications
• Other Study ID Numbers: 2021-0486

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED

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