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Updated: Aug 16, 2026
Determination of Cardiac Output in a Porcine Model for Ex Vivo Pulmonary Perfusion
Published on: June 28, 2024
Assumed oxygen consumption frequently results in large errors in the determination of cardiac output
Ullrich Fakler1, Christian Pauli, Michael Hennig
1Department of Pediatric Cardiology and Congenital Heart Disease, Technische Universität München, Germany. fakler@dhm.mhn.de
Insights
Assumed oxygen consumption values introduce significant errors when calculating cardiac output in pediatric patients with congenital heart disease. Measured values are crucial for accurate Fick principle determinations.
Area of Science:
- Pediatric Cardiology
- Cardiopulmonary Physiology
- Medical Device Technology
Background:
- The Fick principle is a cornerstone for determining cardiac output.
- Accurate oxygen consumption (VO2) measurement is vital for Fick calculations.
- Pediatric congenital heart disease (CHD) populations present unique physiological challenges.
Purpose of the Study:
- To compare assumed versus measured oxygen consumption (VO2) in pediatric CHD patients.
- To evaluate the accuracy of established formulas for VO2 estimation in this population.
- To assess the impact of VO2 discrepancies on cardiac output determination.
Main Methods:
- Studied 143 pediatric patients (2 days to 23.8 years) with CHD undergoing cardiac catheterization.
- Measured VO2 using a Deltatrac II analyzing system.
- Calculated assumed VO2 using Krovetz-Goldbloom and LaFarge-Miettinen formulas.
- Analyzed agreement using Bland-Altman plots and paired t-tests.
Main Results:
- Measured VO2 ranged from 55.2 to 249 mL·min⁻¹·m⁻².
- Krovetz-Goldbloom formula systematically overestimated VO2 (mean difference -53.3 mL·min⁻¹·m⁻²).
- LaFarge-Miettinen formula also overestimated VO2 (mean difference -15.9 mL·min⁻¹·m⁻²).
- Poor agreement observed in Fontan-type circulation subgroup.
Conclusions:
- Assumed VO2 values lead to substantial errors in cardiac output calculations.
- Measured VO2 is essential for accurate hemodynamic assessment in pediatric CHD.
- Clinical reliance on estimated VO2 may compromise patient management.
Objective:
We sought to investigate the differences in assumed and measured oxygen consumption values for the determination of cardiac output by using the Fick principle in a pediatric population with congenital heart disease.
Methods:
The patient population consisted of 143 patients with a mean age of 11.3 years (age range, 2 days to 23.8 years) undergoing cardiac catheterization during general anesthesia and with mechanical ventilation. Oxygen consumption was measured with a standard commercial analyzing system (Deltatrac II; Datex, Engström, Helsinki, Finland). Assumed oxygen consumption values were calculated according to the formulas of Krovetz and Goldbloom and LaFarge and Miettinen. Comparisons between measurements and assumptions were performed by Bland-Altman plots. Two-sided paired t tests were used to assess a difference of the assumed and measured values.
Results:
The range of measured oxygen consumption values was between 55.2 and 249 mL . min -1 . m -2 . The Krovetz-Goldbloom formula led to systematically larger values compared with the measured values (P = .0001; mean difference of -53.3 mL . min -1 . m -2 ; 95% confidence interval, -56.7 to -49.8 mL . min -1 . m -2 ). The use of the LaFarge-Miettinen formula tends to overestimate oxygen consumption (P = .0037; mean difference of -15.9 mL . min -1 . m -2 ; 95% confidence interval, -26.5 to -5.4 mL . min -1 . m -2 ). A similarly poor agreement was found when analyzing a subgroup of 25 patients with Fontan-type circulation.
Conclusion:
The use of assumed instead of measured oxygen consumption values introduces large errors in the determination of cardiac output.
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