REFLECTANCE-MODE PULSE OXIMETRY

虽然脉搏血氧计在过去的几年里被广泛使用

Although pulse oximeters have been used extensively over the last few years in clinical monitoring applications, the theoretical basis of pulse oximetry is still poorly understood. As a result, the development of instrumentation has relied on the slow acquisition of empirical knowledge. Recently, clinicians have expressed interest in the possibility of developing a transcutaneous oximeter that operates in the reflection mode, rather than in the transmission mode. Such a device could be used at many sites on the body, and may enable monitoring during shock and other conditions during which peripheral blood flow is compromised. Using a photon-diffusion model, we have studied the effect of tissue blood volume and other important variables on the calibration of reflectance-mode oximeters employing a variety of sensor configurations. Measurements from gelatin/milk tissue phantoms and skin compare favorably with model predictions. We are now constructing prototype solid-state sensors which will - be used to measure skin reflectance. New methods for determining blood oxygen saturation from remitted intensities will be tested in hypoxic animal models.