Oxygen consumption in infants and children during heart catheterization

Area of Science:

• Pediatric Cardiology
• Physiology

Background:

• Accurate measurement of oxygen consumption (VO2) is vital for hemodynamic assessment in pediatric patients.
• Existing nomograms for VO2 may not fully account for interindividual variability.

Purpose of the Study:

• To establish predictive equations for oxygen consumption in infants, children, and adolescents undergoing diagnostic heart catheterization.
• To identify key factors influencing oxygen consumption across different age groups.

Main Methods:

• Measured oxygen consumption (VO2) in 504 subjects (infants to adolescents) using a semiopen hood system and paramagnetic oxygen analyzer.
• Developed regression equations based on body dimensions (height, weight, body surface area), heart rate, gender, and age.
• Analyzed hematocrit, systemic oxygen saturation, and blood pressure as potential influencing factors.

Main Results:

• In subjects under 3 years, height, weight, and heart rate were significant predictors of VO2/BSA. VO2/BSA was significantly lower in infants <3 months.
• In subjects 3 years and older, gender, BSA, and HR were significant predictors, with distinct regression equations for males and females.
• Hematocrit, oxygen saturation, and blood pressure were not significant factors.

Conclusions:

• Oxygen consumption is influenced by age, body size, and heart rate, with gender also playing a role in older children and adolescents.
• Regression equations derived from this study provide a more accurate prediction of VO2 than general nomograms.
• Direct measurement of oxygen consumption is preferred for hemodynamic assessment, and caution is advised when using nomograms due to wide confidence intervals.