Diffuse optical measurement of hemoglobin and cerebral blood flow in rat brain during hypercapnia, hypoxia and cardiac arrest.

We have demonstrated the ability to concurrently measure relative changes in cerebral blood flow, hemoglobin concentration, and hemoglobin oxygenation with a single non-contact, non-invasive instrument. Our measurements from rat hypercapnia, hypoxia and cardiac arrest models are in reasonable agreement with the literature, and offer the possibility for further growth and quantification. The optical techniques used in this study are attractive also because they enable experimenters to measure vascular response of deep tissues. The new instrument and concept may also be applicable to human studies especially in infants and neonates permitting noninvasive monitoring of cerebral hemodynamics and oxygen (see [4] and [2] for examples of NIR spectroscopy).