1. 생체계측 II Report # 송성진
Medical Instrumentation II

2. 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

3. 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

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

5. 2. NIBP Cuff pressure Cuff Spuit Stethoscope
Medical Instrumentation II

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

7. • 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

8. • 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

9. • 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

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

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

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

13. 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

14. • 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

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

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

17. 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