Brain death is an irreversible loss of all brain functions, while deep coma is a profound state of unconsciousness associated with depressed cerebral activity. Timely distinguishing the two states is crucial for saving patients. The noninvasive, sensitive, universally available, and timely ancillary method to assess brain death and deep coma has not been established. This study aims to explore a noninvasive and straightforward way in brain death and deep coma online assessment. The changes of hemodynamic parameters including oxyhemoglobin (HbO2) and deoxyhemoglobin (Hb) were detected by near infrared spectroscopy instrument attached on the forehead of participators. A multiple-phase protocol at varied fraction of inspired O2(FIO2) were utilized during the assessment. Then the investigators compared the multiple physiological parameters changes among different groups at different FIO2.
This study aims to assess brain death and deep coma with the self-made near infrared spectroscopy (NIRS) instrument. The investigators used the noninvasive method to monitor the Δ[HbO2] (the concentration changes in oxy-hemoglobin) and Δ[Hb] (the concentration changes in deoxy-hemoglobin) in the region around the forehead of medically evaluated participating patients and healthy subjects. A multiple-phase protocol at varied fraction of inspired O2 were utilized during the assessment.