UC Irvine

Time Resolved-Near-infrared spectroscopy (TR-NIRS) is a non-invasive, non-harmful tool to assess the oxygenation status of tissue-specific myoglobin and hemoglobin. A series of studies was done to assess differences in muscle oxygenation during exercise between healthy children and adults and in children with sickle cell anemia. The first study demonstrated a novel tissue water correction to improve the accuracy of TR-NIRS-determined hemoglobin/myoglobin of vastus lateralis muscle with varying adipose tissue thickness. This correction allows for more accurate comparisons between groups with systematically different adipose tissue thicknesses. This novel correction was incorporated into the second study which compared the NIRS-determined muscle oxygenation patterns of early pubertal boys and girls, late pubertal boys and girls, and young men/women during a ramp-style progressive exercise test on a cycle ergometer. This revealed a different pattern in maintaining oxygen supply in late pubertal boys and young men compared to the other groups. The last study presented pilot data from mid/late pubertal children with sickle cell anemia during a ramp-style cycle ergometer test. Children with sickle cell anemia did not increase their total muscle hemoglobin/myoglobin during exercise and had drastically lower muscle oxygenation throughout exercise compared to healthy controls. Together, these studies provide compelling evidences for the usefulness of TR-NIRS as a tool to assess muscle oxygenation in healthy and diseased children and to provide a way for quantitative assessment of intervention success and effect.