Clinical trial NCT03970980: FIO2 Influences Accuracy of Fick-based Cardiac Output
Official title: Increasing FIO2 Influences Accuracy of Fick-based Assessments of Cardiac Output in Cardiac Surgery Patients
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: NA
Conditions: Cardiac Output
Keywords: Fick Principle
Lead sponsor: Chang Gung Memorial Hospital
Sponsor class: OTHER
First posted: 2019-06-03
Enrollment: 24
Sex: ALL
Minimum age (years): 20
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: no
Allocation: RANDOMIZED
Intervention model: PARALLEL
Primary purpose: OTHER

Brief summary: Cardiac output (CO) monitoring is often required for clinical evaluation and management in critically ill patients and during anesthesia. There are many methods to measure CO. Fick-based CO estimation (Fick-CO) is one of the most commonly used methods, while thermodilution (TD-CO) is viewed as golden standard. But Fick-CO is still widely used, especially in catheterization laboratories and pediatric cardiologic department, whose patients often with congenital heart disease. Multiple studies from the 1960s find a strong correlation between TD-CO and Fick-CO. However, more recent studies reject the conclusion. Since Fick-CO is the ratio of oxygen consumption (V'O2) to the arteriovenous difference in oxygen content, many parameters are included in the Fick equation, such as V'O2, hemoglobin (Hb), arterial oxygen saturation (SaO2), mixed venous oxygen saturation (SvO2), partial pressure of arterial oxygen (PaO2), and mixed venous oxygen tension (PvO2). Any changes of each parameter may influence the accuracy of Fick-CO calculation. This may be the reason why it remains controversial whether Fick-CO and TD-CO are interchangeable or not. Although there are lots of studies comparing Fick-CO and TD-CO, discussing the impact of V'O2 on Fick-CO, how the other parameters influence the final CO estimation are rarely focused. Therefore, the purpose of this study was to assess the influence of FIO2 on PaO2, SvO2, PvO2, and the accuracy of Fick-CO in cardiac surgery patients.

Detailed description: Patients who are aged ≥20 years, are undergoing planned elective cardiac surgery, and provided signed informed consent are included in the present study. Any patients with cardiac arrhythmia or an intra-cardiac shunt are excluded.

The patients are randomly assigned to 2 groups: FIO2 \<70% or FIO2 \>90%. And during the surgery, the oximeter values are kept ≥98%. Intra-operatively, FIO2, PaO2, SvO2, PvO2, Hb, and TD-CO are recorded.

Eligibility criteria: Inclusion Criteria:

* undergoing planned elective cardiac surgery
* agree to sign informed consent

Exclusion Criteria:

* cardiac arrhythmia
* intra-cardiac shunt

Primary outcomes:
measure: The Hemoglobin Values in Different FIO2 Groups during Cardiac Surgeries
timeFrame: 5 minutes before surgical incision
measure: The Hemoglobin Values in Different FIO2 Groups during Cardiac Surgeries
timeFrame: 5 minutes after finishing protamine infusion
measure: The Oxygen Consumption in Different FIO2 Groups during Cardiac Surgeries
timeFrame: 5 minutes before surgical incision
measure: The Oxygen Consumption in Different FIO2 Groups during Cardiac Surgeries
timeFrame: 5 minutes after finishing protamine infusion
measure: The SaO2 in Different FIO2 Groups during Cardiac Surgeries
timeFrame: 5 minutes before surgical incision
measure: The SaO2 in Different FIO2 Groups during Cardiac Surgeries
timeFrame: 5 minutes after finishing protamine infusion
measure: The SvO2 in Different FIO2 Groups during Cardiac Surgeries
timeFrame: 5 minutes before surgical incision
measure: The SvO2 in Different FIO2 Groups during Cardiac Surgeries
timeFrame: 5 minutes after finishing protamine infusion
measure: The PaO2 in Different FIO2 Groups during Cardiac Surgeries
timeFrame: 5 minutes before surgical incision
measure: The PaO2 in Different FIO2 Groups during Cardiac Surgeries
timeFrame: 5 minutes after finishing protamine infusion
measure: The PvO2 in Different FIO2 Groups during Cardiac Surgeries
timeFrame: 5 minutes before surgical incision
measure: The PvO2 in Different FIO2 Groups during Cardiac Surgeries
timeFrame: 5 minutes after finishing protamine infusion
Secondary outcomes:
measure: The Precision of Fick-based Cardiac Output in Different FIO2 Groups during Cardiac Surgeries
timeFrame: 5 minutes before surgical incision
measure: The Precision of Fick-based Cardiac Output in Different FIO2 Groups during Cardiac Surgeries
timeFrame: 5 minutes after finishing protamine infusion
Other outcomes:
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