NONINVASIVE BLOOD ANALYSIS DURING MANNED SPACE FLIGHT

A SPECTROSCOPIC APPROACH WILL BE DEVELOPED FOR ANALYSIS OF BLOOD DURING MANNED SPACE MISSIONS. THE ANALYSIS WILL BE PERFORMED DIRECTLY THROUGH THE SKIN BY USING LIGHT FROM A LASER DIODE ARRAY THAT IS REFLECTED FROM A PROMINENT VEIN NEAR THE SKIN SURFACE, IN EITHER THE WRIST OR ANKLE REGION OF THE BODY. THE LASER DIODES WILL OPERATE AT LOW POWER, CAUSING NO TISSUE INJURY, AND AT SPECIFIC WAVELENGTHS IN THERED AND NEAR-INFRARED WAVELENGTHS, AT WHICH SKIN AND VENOUS TISSUE ARE KNOWN TO BE TRANSPARENT TO A DEPTH OF SEVERAL MILLIMETERS. THE REFLECTED LIGHT AT EACH OF THE SELECTED PROBE WAVELENGTHS WILL THEN BE MEASURED. THE REFLECTED INTENSITIES FROM EACH PROBE WAVELENGTH ARE ANALYZED IN TWO MODES. FIRST, THE SPECIFIC REFLECTANCE RATIOS AMONG THE PROBE WAVELENGTHS WILL BE DETERMINED AND USED TO IDENTIFY BLOOD COMPONENTS PRESENT IN THE MONITORED PATIENT'S CIRCULATORY SYSTEM. THEN, IF THE RATIOS OF KEY SELECTED WAVELENGTHS REMAIN UNCHANGED, THE REFLECTANCE INTENSITY WILL BE USED TO MONITOR CHANGES IN RED-CELL (HEMATOCRIT) CONCENTRATION. A SPECTROSCOPIC APPROACH WILL BE DEVELOPED FOR ANALYSIS OF BLOOD DURING MANNED SPACE MISSIONS. THE ANALYSIS WILL BE PERFORMED DIRECTLY THROUGH THE SKIN BY USING LIGHT FROM A LASER DIODE ARRAY THAT IS REFLECTED FROM A PROMINENT VEIN NEAR THE SKIN SURFACE, IN EITHER THE WRIST OR ANKLE REGION OF THE BODY. THE LASER DIODES WILL OPERATE AT LOW POWER, CAUSING NO TISSUE INJURY, AND AT SPECIFIC WAVELENGTHS IN THERED AND NEAR-INFRARED WAVELENGTHS, AT WHICH SKIN AND VENOUS TISSUE ARE KNOWN TO BE TRANSPARENT TO A DEPTH OF SEVERAL MILLIMETERS. THE REFLECTED LIGHT AT EACH OF THE SELECTED PROBE WAVELENGTHS WILL THEN BE MEASURED. THE REFLECTED INTENSITIES FROM EACH PROBE WAVELENGTH ARE ANALYZED IN TWO MODES. FIRST, THE SPECIFIC REFLECTANCE RATIOS AMONG THE PROBE WAVELENGTHS WILL BE DETERMINED AND USED TO IDENTIFY BLOOD COMPONENTS PRESENT IN THE MONITORED PATIENT'S CIRCULATORY SYSTEM. THEN, IF THE RATIOS OF KEY SELECTED WAVELENGTHS REMAIN UNCHANGED, THE REFLECTANCE INTENSITY WILL BE USED TO MONITOR CHANGES IN RED-CELL (HEMATOCRIT) CONCENTRATION.