| 摘要 |
A system for assessing organ function has a plurality of light emitters of distinct spectral characteristics are coupled into a percutaneous fiber delivery assembly with a tip extending to or into an internal organ to illuminate organ tissue. The assembly includes a delivery optical fiber, and a collection fiber that collects and returns light scattered, reflected or emitted by the surrounding tissue to a detector at the proximal end. The device also senses temperature at the tip. Control and processing modules drive the laser diodes and process the return signals. The instrument may assess general metabolic activity by detecting light absorption of a linked substance, for example at a peak attributed to deoxygenated hemoglobin and/or at one or more peaks attributed to oxygenated hemoglobin. Preferably, change of a parameter such as pulse oxygen saturation together with one or more other parameters such as temperature are detected to provide an indication of organ function, e.g., the onset of shock. A prototype used four different laser diodes having peaks at 735, 760, 805 and 890 nm connected to a single optical fiber and driven at about 50 to 100 mW to illuminate organ tissue. A front-end splitter provides a reference beam to a photo detector to normalize the detection output in the return fiber, and dark current is subtracted to correct the signal samples. In other embodiments, a coupler may be fabricated from a multimode fiber with an SMA connector as an end coupler. The photo detector may be a broad band detector useful over a range, for example, of 320 to 1100 nanometers, and with a detection threshold of under a milliwatt. When used in a fluorescence mode the device may perform detection after filtering the diode or return signal with one or more narrow band filters, and the illumination and collection intervals may be offset to maximize signal collection or minimize interference. The percutaneous probe may be configured for catheter insertion or may have its fibers and electrical connections contained within a piercing sleeve that is itself capable of insertion directly through the skin and into an organ. Preferably, a control module allows the user to adjust data acquisition parameters and view the output signal quality as well as the measured or calculated parameters derived from the acquired signals. The processor may further control a firing sequence of the laser diodes, timing and size of the signal samples and data stores. The device may include a plurality of laser diodes of which only a portion are selected for each assay so as to tailor the spectral illumination to a different intended targeted enzyme, metabolite or other compound, and the processor may include heuristic correlators for interpreting the physiological state or detecting the onset of shock based on magnitudes of the multiple different measured parameters.
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