New prototype NIRS instrument [corrected] to investigate multi-regional cerebral blood and tissue oxygenation 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 research 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 the conversion of the continuous wave NIRS single-channel instrument (NIRDCU) into a prototype four-channel instrument which can be used to provide continuous multi-regional information regarding the cerebral blood oxygenation and haemodynamics in the frontal, left parietal, right parietal and occipital region of the neonatal brain. This has been achieved by attaching an optical multiplexing system to the NIRDCU to select different transmitting and receiving fibres, thus addressing different regions in the brain. Preliminary laboratory tests on a phantom and on the adult forearm are presented, illustrating the practicality of regional monitoring.