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생체계측 II Report #9 2005200427 송성진. Chap 8. Part I. Flow and Volume of Blood. <Topics Covered in Chapter 8> Cardiac Output Fick Technique Method Indicator Dilution Thermodilution Electromagnetic Flowmeter (Not good) Ultrasound Flowmeters
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생체계측 II Report #92005200427 송성진 Medical Instrumentation II
Chap 8. Part I. Flow and Volume of Blood <Topics Covered in Chapter 8> • Cardiac Output Fick Technique Method Indicator Dilution Thermodilution • Electromagnetic Flowmeter (Not good) • Ultrasound Flowmeters • Plethysmography Medical Instrumentation II
1. Indicator Dilution Method • Fick Method • Indicator Dilution using rapid injection • Thermodilution Medical Instrumentation II
(Infusion rate) -> We Known (Mass balance equation) Conclusion : Medical Instrumentation II
Substitution of Equation! Fick Method (O₂ Consumption, L/min) measure By Spirometer (O₂ density of Artery Blood) (O₂ density of Vein Blood) Medical Instrumentation II
Dye Dilution Method Indicator Dilution using rapid injection Indocyanine green (cardiogreen) Indictor dilution curve Recirculation Extrapolation Bolus injection Medical Instrumentation II
Find Area! Conclusion : Medical Instrumentation II
Weak Point : Once dye get an injection, it remains in our body. The dye should be excreted in the urine. In order to remeasure the blood flow, you should wait for a long time. Medical Instrumentation II
Thermodiltion (standard) Using 4 lumen catheter (Swan-Ganz catheter) Bolus injection Weak Point : We unknown temperature of Right artium. Medical Instrumentation II
Conclusion : (Heat content of injectate) (Blood density) (Specific heat of blood) Medical Instrumentation II
2. Ultra Sound -> pressure element, approvaled by 1MHz frequency. Ex) Primary Echo skin No reflection Medical Instrumentation II
Far field Near field Medical Instrumentation II
Transit Time Flowmeter Velocity of ultrasound. Velocity of RBC, WRC, and plate. Medical Instrumentation II
i ) Down stream ( = Blood flow direction) ii ) Up stream ( = Blood flow reverse direction) Because… C >> ucosφ Conclusion : Medical Instrumentation II
Continuous Doppler Flowmeter Doppler frequency shift Ex) aviation, ship, submarine… Medical Instrumentation II
Pulsed Doppler Flowmeter Flow profile measurement Medical Instrumentation II
Thermal Convection Flowmeter Thermister i ) Bias current -> Thermister heating ii ) T₂Thermister is cooled by thermal convection Weak Point : Invasive and Probe position is difficult. Medical Instrumentation II
3. Plethysmography -> Volume, blood flow measurement Howland Current Source ` V Cuf f Artery open Vein close Medical Instrumentation II
Volume Normal Slope = flow Venous Thrombosis Arterial Cuff On Cuff Out Medical Instrumentation II
Part II. Pulmonary Function Test Patient monitoring (Respiration monitoring) 1. Architecture Area Trachea Bronchus Alveoli Because… O₂ & CO₂ diffusion at alveoli Medical Instrumentation II
2. Physiological Functions • O₂ transport into blood stream • CO₂ removal from blood stream • Homeostasis of pH, Po₂, Pco₂ Medical Instrumentation II
3. Respiration • Ventilatory mechamis - RC equivalent circuit model • Gas transport - Mass balance equation(Diffusion process) Medical Instrumentation II
4. Pressure measurement Differential pressure transducer i ) Diaphragm ii ) Diaphragm Medical Instrumentation II
iii ) Differential pressure sensor Mouth Mesh screen Flow Conclusion : Medical Instrumentation II
Ballon Hole Ballon sensor Pressure sensor Gas Switch On -> Switch Off -> Metal switch MP Control Air pump Medical Instrumentation II Pressure
5. Flow measurement • Rotating Vane • Ultrasound Flowmeter • Thermal Convection Flowmeter • Pneumotachometer (standard) Medical Instrumentation II
6. Volume measurement -> Plethysmography IC VC TLC FRC TV (Tidal Volume) RV ERC Weak Point : It is Relative value, not absolute value. Medical Instrumentation II
Rotating Paper Water Spirometer Air Water Pen Mouth CO₂ absorber Medical Instrumentation II
Mouth Dry Spirometer Valve Air (gas) Inspiratory gas Expiratory gas Piston Gas is Separated by two section Medical Instrumentation II
7. FRC measurement He dilution technique - patient at FRC - prepare a spirometer of volume VSP and initialHe, concentration of fIHE - patient breaths tooth spirometer - find He concentration of expiration F Medical Instrumentation II
N₂ washout technique - patient at FRC - prepare a spirometer of O₂, VSP - patient breaths to the spirometer - Measure N₂ concentration in (FFN₂) the expiratory. Medical Instrumentation II
8. Gas concentration measurement • Mass spetroscophy • Gas chromatography • Infrared spectrography • Raman spectrography • Emission spectrography • Paremagnetic O₂ analyzer Medical Instrumentation II
9. Gas transport measurement Gas distribution test (Single breath N₂ wachout) - RC -> TLC O₂ inspiration - Pause (hold breath) - Expiration and measure fN2 Medical Instrumentation II
Diffusion test (CO diffusion capacity) - Inspire ω, He in air - fICO, fIHe - Hold breath for 10sec - Expire to measure FFCO, FFHe Medical Instrumentation II