생체계측 II Report #5 2005200427 송성진 Medical Instrumentation II

Chap 7. Blood pressure and sound 1. Blood pressure : Invasive blood pressure Non-invasive blood pressure 2. Intraocular pressure : Tonometry 3. Stethoscope Medical Instrumentation II

P P 1. Tonometry Force per unit Area F = Mg (We Known factor) Contact Area = A M P P F Ball Ball Force per unit Area Medical Instrumentation II

• Measurement structure LED Intraocular pressure Photo Sensor Ex) Photo diode & Photo Transistor Medical Instrumentation II

2. NIBP Cuff pressure Cuff Spuit Stethoscope Medical Instrumentation II

• Heart structure Pulmonary artry Superior Pulmonary Vein Venacava Coronary artery Coronary vein Aorta Inferior Systemic circulation Pulmonary circulation Coronary circulation Medical Instrumentation II

• Blood pressure graph Systolic pressure Diastolic pressure 120mmHg 90mmHg Diastolic pressure NIBP measure the value of systolic & diastolic pressure. Also It isn’t the print graph Medical Instrumentation II

• About PCB (Printed Circuit Board) PCB is Classified MLB(Multi layer Board), Double substrate Spec Circuit design CAD : schematic (OrCAD) CAD : layout(OrCAD) PCB produce Components apply Test & programming Debugging Medical Instrumentation II

• Automatic Blood pressure graph & principle Blue is pressurize Red is decompress P Systolic pressure 120mmHg 80mmHg Cuff pressure decrease -2 ~ -3 mmHg / sec Diastolic pressure Cuff > inner vessel Medical Instrumentation II

Osillometric Method • Blood pressure sound graph Noise Heart sound graph Osillometric Method Medical Instrumentation II

3. Invasive BP measurement • Catheter Diaphragm is flexible Dome Diaphragm Saline Strain gage Pi Po Cable Blood vessel Medical Instrumentation II

Catheter have several trouble!!! Pi(t) Po(t) ≠ t t Catheter have several trouble!!! Length Diameter Material Air bubble in Catheter Medical Instrumentation II

Equivalent circuit model of catheter – sensor system Voltage, v, [V]  Pressure, P, [pa] Current, i, [A=C/s]  Moving flow, f, [m³/s] Charge, q, [C]  Volume, v, [m³] EX) m f = mg (Center of Mass ) M Air potential Hight ↑ Pressure ↓ F = Mg A Medical Instrumentation II

• Apply measurement Blood flow is applied Current Dome Diaphragm Saline Strain gage Pi Po Cable Blood vessel Pi & Po is applied voltages Length is applied resistor, Capacitor and Conductor Medical Instrumentation II

Pipe represent Resistor. Resistance A L EX) P1 Pipe represent Resistor. As length & diameter. P2 Medical Instrumentation II

Pressure is increasing, Compliance is increasing 2. Capacitance of compliance Pressure is increasing, Compliance is increasing Young’s modulus Medical Instrumentation II

3. Inductance / Inertance Mass is increasing, innersure is increasing, And inductance is increasing As a result, current flow (di/dt) is decreasing. Medical Instrumentation II