New prototype NIRS to investigate multi-regional cerebral blood and tissueoxygenation and haemodynamics

Near infra-red spectroscopy (NIRS) is a non-invasive optical technique used to assess blood and tissue oxygenation and haemodynamics in living tissue. It is presently used as a semi-continuous monitoring technique on a resear ch basis. Multi-regional NIRS information could be beneficial for a better understanding of the development of cerebral injuries and the reduction of neurodevelopmental abnormalities in the human newborn. The paper presents t he conversion of the continuous wave NIRS single-channel instrument (NIRDCU ) into a prototype four-channel instrument which can be used to provide con tinuous multi-regional information regarding the cerebral blood oxygenation and haemodynamics in the frontal, left parietal, right parietal and occipi tal region of the neonatal brain. This has been achieved by attaching an op tical multiplexing system to the NIRDCU to select different transmitting an d receiving fibres, thus addressing different regions in the brain. Prelimi nary laboratory tests on a phantom and on the adult forearm are presented, illustrating the practicality of regional monitoring.