CONTINUOUS OXYGEN TENSION AND PERFUSION MEASUREMENT SYS.

THIS PROJECT WILL ADDRESS THE CRITICAL NEED FOR REAL-TIME, CONTINUOUS QUANTIFICATION OF LOCAL TISSUE PERFUSION, OXYGEN TENSION, AND TEMPERATURE IN VIVO. THE FEASIBILITY OF COMBINING IN A MINIATURE HYBRID THERMISTOR-POLAROGRAPHIC OXYGEN SENSOR BOTH THE UNIQUE CAPABILITY OF THE EXTENDED THERMAL DIFFUSION PROBE (ETDP) AND RECENT ADVANCES IN OXYGEN TENSION MEASUREMENTS WILL BE INVESTIGATED. A PLATINUM WIRE WILL BE ENCAPSULATED IN THE GLASS COATING OF ATHERMISTOR BEAD, RECESSED ELECTROCHEMICALLY, AND GOLD PLATEDTO SERVE AS A FLOW-INSENSITIVE OXYGEN SENSOR. THE ETDP SYSTEM CURRENTLY QUANTIFIES TEMPERATURE TO +0.003 DEGREES CENTIGRADE AND PERFUSION TO +10 PERCENT OVER THE RANGE OF PHYSIOLOGIC FLOWS. THE ETDP CIRCUITRY AND SOFTWARE WILL BE EXPANDED TO MEASURE OXYGEN TENSION TO +1 MM/HG, EITHER IN A STEADY-STATE MODE OR IN A TRANSIENT MODE WHEN ADDITIONAL PRECISION IS DESIRED. THE LONG-TERM STABILITY OF THE HYBRID SENSOR WILL BE DETERMINED. THIS INTEGRATED SYSTEM WILL PERMIT INVESTIGATION OF PERFUSION, TEMPERATURE, AND OXYGEN TENSION (AND THEIR INTERRELATIONSHIPS) IN THE SAME TISSUE VOLUME. THIS CAPABILITY IS IMPORTANT FOR MANY RESEARCH AND CLINICAL STUDIES, INCLUDING DETERMINATION OF THE EFFECTIVENESS OF PHARMACOLOGIC MANIPULATIONS IN DIFFERENT EXPERIMENTAL AND CLINICAL STATES OF CIRCULATORY SHOCK (A CONDITION RESPONSIBLE FOR 250,000 AMERICAN DEATHS YEARLY), FOR EXAMINING THE EFFECT OF LOCAL PERFUSION AND OXYGEN TENSION ON VENTRICULAR ARRHYTHMIAS, AND FOR MONITORING THE VARIOUS FORMS OF THROMBOLYTIC THERAPY FOR CORONARY ARTERY OCCLUSION.