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

When calculating cardiac index (C.I.) by the Fick method, oxygen consumption (VO 2 ) is often unknown, so assumed values are typically used. This practice introduces a known source of inaccuracy into the calculation. Using a measured VO 2 (mVO 2 ) 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 VO 2 (aVO 2 ). mVO 2 was recorded for all patients undergoing cardiac catheterization with general anesthesia and controlled ventilation during the study period. mVO 2 was compared to the reference VO 2 (refVO 2 ) 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 VO 2 measurements were obtained, including 71 with a corresponding cMRI or TD measure of cardiac index for validation. mVO 2 demonstrated satisfactory concordance and correlation with the TD- or cMRI-derived refVO 2 (ρ c  = 0.73, r 2  = 0.63) with a mean bias of - 3.2% (SD ± 17.3%). Assumed VO 2 demonstrated much weaker concordance and correlation with refVO 2 (ρ c  = 0.28, r 2  = 0.31) with a mean bias of + 27.5% (SD ± 30.0%). Subgroup analysis of patients < 36 months of age demonstrated that error in mVO 2 was not significantly different from that observed in older patients. Many previously reported prediction models for assuming VO 2 performed poorly in this younger age range. Measured oxygen consumption using the E-sCAiOVX module is significantly more accurate than assumed VO 2 when compared to TD- or cMRI-derived VO 2 in a pediatric catheterization lab.