Non-invasive detecting cerebral hemoglobin concentration of newborns during oxygen inhalation using near-infrared spectroscopy

Human tissue oxygenation status can be completely described by the absolute values of the tissue hemoglobin concentrations. To detect them non-invasively and conveniently using continuous-wave near infrared spectroscopy (NIRS), the “in vivo calibration” algorithm was adopted. Three newborns were discussed during oxygen inhalation. By comparing the absorption coefficient before and after the change of tissue oxygenation induced by oxygen inhalation, the cerebral reduced scattering coefficient was calculated when the correlation coefficient R was above 0.75. Then the cerebral oxy- and deoxy-hemoglobin concentrations were derived based on the solution of steady-state diffusion equation. The total hemoglobin concentration of brain tissue was 50.1±6.1μM, which was consistent with most of the recent reports. In summary, even though further discussions are needed, the “in vivo calibration” method is effective and relatively accurate to detect human tissue hemoglobin concentrations.