Measured Oxygen Consumption During Pediatric Cardiac Catheterization is More Accurate than Assumed Oxygen Consumption.

Abstract

When calculating cardiac index (C.I.) by the Fick method, oxygen consumption (VO₂) is often unknown, so assumed values are typically used. This practice introduces a known source of inaccuracy into the calculation. Using a measured VO₂ (mVO₂) from the CARESCAPE E-sCAiOVX module provides an alternative that may improve accuracy of C.I. calculations. Our aim is to validate this measurement in a general pediatric catheterization population and compare its accuracy with assumed VO₂ (aVO₂). mVO₂ was recorded for all patients undergoing cardiac catheterization with general anesthesia and controlled ventilation during the study period. mVO₂ was compared to the reference VO₂ (refVO₂) determined by the reverse Fick method using cardiac MRI (cMRI) or thermodilution (TD) as a reference standard for measurement of C.I. when available. 193 VO₂ measurements were obtained, including 71 with a corresponding cMRI or TD measure of cardiac index for validation. mVO₂ demonstrated satisfactory concordance and correlation with the TD- or cMRI-derived refVO₂ (ρ_c = 0.73, r² = 0.63) with a mean bias of - 3.2% (SD ± 17.3%). Assumed VO₂ demonstrated much weaker concordance and correlation with refVO₂ (ρ_c = 0.28, r² = 0.31) with a mean bias of + 27.5% (SD ± 30.0%). Subgroup analysis of patients < 36 months of age demonstrated that error in mVO₂ was not significantly different from that observed in older patients. Many previously reported prediction models for assuming VO₂ performed poorly in this younger age range. Measured oxygen consumption using the E-sCAiOVX module is significantly more accurate than assumed VO₂ when compared to TD- or cMRI-derived VO₂ in a pediatric catheterization lab.