Abstract 19033: Hyperoxia Reduces Oxygen Consumption in Children With Pulmonary Hypertension

Background: High inspired oxygen concentration (FiO2) and inhaled nitric oxide (iNO), either alone or in combination, are administered to test pulmonary vasoreactivity in children. Oxygen consumption (VO2) cannot be measured accurately with conventional methods if the inspired FiO2 >0.85 and it is usually assumed that (VO2) does not change with hyperoxia or iNO. Hypothesis: We hypothesised that an inspired FiO2 >0.85 would change VO2 compared with VO2 in room air (RA) and iNO administered with room air and could influence the accuracy of flow calculations using the direct Fick’s equation. Methods: We reviewed retrospectively the cardiac catheterization data obtained between 2009-14 in children with pulmonary hypertension (PH) without cardiac shunts and cardiac output (CO) measured by thermodilution in 3 conditions of RA, with an FiO2 >0.85 and iNO in RA. VO2 was calculated using the Fick equation CO= VO2 / arterial-venous oxygen content difference. Dissolved O2 was included in the calculation. Results: Da...