SPECTROSCOPY OF BRAIN ENERGY STATE AND OXYGEN DELIVERY

THE CONCURRENT EVALUATION OF BRAIN ENERGY STATE AND OXYGEN DELIVERY PROVIDES A UNIQUE APPROACH TO "EARLY WARNING" OF HYPOXIC/ISCHEMIC STRESS. NEAR INFRARED SPECTROSCOPY OF OXYGEN DELIVERY BY HEMOGLOBIN GIVES AN APPROXIMATION TO THE OXYGENATION OF THE CAPILLARY BED OF THECORTICAL LAYERS OF THE NEONATE BRAIN. SPEED OF RESPONSE OF THE OPTICAL METHOD IS HIGH (.1 SEC OR LESS), AND APPROPRIATETO SUDDEN CHANGES OF OXYGEN DELIVERY, FOR EXAMPLE, IN APNEA. HOWEVER, THE RELATIONSHIP BETWEEN OXYGEN DELIVERY AND ENERGY METABOLISM IS UNCERTAIN. PHOSPHORUS MAGNETIC RESONANCE SPECTROSCOPY GIVES PRECUSE AND CRITICAL INFORMATION OF THE ENERGY STATE OF THE BRAIN IN TERMS OF THEPHOSPHOCREATINE/PHOSPHATE RATIO, WHICH IS IN TURN RELATED TOTHE PHOSPHATE POTENTIAL (ATP/ADP X P(1)) (1). THE NMR METHOD IS NOT FAST, 5 MINUTES MAY BE REQUIRED FOR A DEFINITE VALUE, AND THUS, CANNOT SERVE AS A FAST "EARLY WARNING" OF HYPOXIC DISTRESS. THE DEVICE PROPOSED COMBINES TRANSCUTANEOUS INFRARED SPECTROSCOPY OF OXYGEN DELIVERY AS ARAPIDLY RESPONDING EARLY WARNING TOGETHER WITH PMRS AS A SLOWER, BUT MORE PRECISE, QUANTITATIVE EVALUATION OF DANGER. THESE TWO DEVICES IN COMBINATION CAN BE USED FOR THE INITIATION OF AGGRESSIVE THERAPY BY MANUAL AND AUTOMATICCONTROL OF THE OXYGEN DELIVERY TO THE BRAIN. THIS PHASE I APPLICATION HAS TO DO WITH TESTS OF SIMPLIFIED SPECTROPHOTOMETRIC TECHNIQUES FOR MEASUREMENT OF CAPILLARY BED OXYGENATION OF HEMOGLOBIN. TWO DEVICES ARE DESCRIBED, ONE EMPLOYING HOLOGRAPHIC GRATING MONOCHROMATORS AND THE OTHER TIME-SHARING INTERFERENCE FILTER SPECTROPHOTOMETRY. PHASE II DEVELOPMENTS INCLUDE DISPERSIVE DETECTOR SYSTEMS.