How was the OxiFirst System calibrated?
A fetal oximeter must be empirically calibrated over a range of low oxygen saturations that cannot be safely or ethically obtained in breathe-down studies using adult human volunteers. Additionally, there is no practical way to reliably and repeatedly obtain arterial blood from a human fetus during labor to conduct such a study. Therefore, the OxiFirst system was calibrated in carefully controlled hypoxia studies in a laboratory animal model. This calibration was validated by data collected in a separate animal study conducted by independent investigators at a different site using a similar protocol. Oxygen saturation readings obtained with the calibrated OxiFirst system were also compared to laboratory hemoximeter values in a series of critically ill infants and children with congenital heart disease or severe respiratory failure. The OxiFirst system is specifically designed and calibrated for use on the fetus with oxygen saturations less than 85%. Unreliable results can occur if used
