Preliminary evaluation of a prototype spatially resolved spectrometer

Near infrared spectroscopy (NIRS) has become an established research tool and is now being explored in several clinical settings [7]. However, until recently NIRS has not been fully quantified and changes have been difficult to interpret [4]. A new development by Hamamatsu Photonics, called the Spatially Resolved Spectrometer (SRS), proposes to be able to give a quantitative measure of oxygen saturation. We have incorporated the SRS into a multimodality monitoring system in three different clinical situations: 1) patients undergoing routine cardiopulmonary bypass, 2) head injured patients and 3) patients undergoing right-sided carotid endarterectomy. The importance of this investigation is in the development of the SRS machine which shows potential as a useful clinical tool. The results demonstrated good correlation between SRS and jugular venous oximetry (SjO2) in about 50% of patients. Although these results are encouraging, this study suggests that the SRS, in its present form, is not a reliable clinical monitor of cerebral oxygen saturation.