생체계측 ii report #9 2005200427 송성진
DESCRIPTION
생체계측 II Report #9 2005200427 송성진. Chap 8. Part I. Flow and Volume of Blood. Cardiac Output Fick Technique Method Indicator Dilution Thermodilution Electromagnetic Flowmeter (Not good) Ultrasound Flowmeters - PowerPoint PPT PresentationTRANSCRIPT
생체계측 II Report #9
2005200427 송성진
Medical Instrumentation II
<Topics Covered in Chapter 8>
• Cardiac Output Fick Technique Method Indicator Dilution Thermodilution• Electromagnetic Flowmeter (Not good)• Ultrasound Flowmeters• Plethysmography
Medical Instrumentation II
Chap 8. Part I. Flow and Volume of Blood
1. Indicator Dilution Method
• Fick Method• Indicator Dilution using
rapid injection• Thermodilution
Medical Instrumentation II
Medical Instrumentation II
iF oF FFF oi )(densityCi )(densityCo
dt
dm(Infusion rate) -> We Known
FCdt
dmFC oi (Mass balance
equation)
min/min// gllg
io CCdt
dmflowF )(Conclusio
n :
Fick Method
Medical Instrumentation II
dt
dm
Substitution of Equation!
ao CC
vi CC
(O₂ density of Artery Blood)
(O₂ density of Vein Blood)
(O₂ Consumption, L/min)measure By Spirometer
Indicator Dilution using rapid injection
Medical Instrumentation II
Dye Dilution MethodIndocyanine green (cardiogreen)
Extrapolation
Indictor dilution curve
)(tC
tBolus injection
Recirculation
Medical Instrumentation II
Find Area!
)(tCdv
dm dvtCdm )(
FtCdt
dvtCdvtC
dt
d
dt
dm )()()(
TT
dttCFdmm00
)(
T
dttC
mF
0)(
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.
Thermodiltion (standard)
Medical Instrumentation II
T
tBolus injection
Weak Point : We unknown temperature of Right artium.
Using 4 lumen catheter(Swan-Ganz catheter)
Medical Instrumentation II
]/[)(
3
0
smdttTC
QF T
bbb
Conclusion :
][JCTVQ iiii (Heat content of injectate)
]/[ 3mkgb
]/[ KkgJCb
(Blood density)
(Specific heat of blood)
Medical Instrumentation II
-> pressure element, approvaled by 1MHz frequency.Ex)
t
No reflection
Primary Echo
skin
2. Ultra Sound
Medical Instrumentation II
2
f
v
MHzf
3
Near field
Far field
D
2.1sin
Transit Time Flowmeter
Medical Instrumentation II
Du
Velocity of RBC, WRC, and plate.
c Velocity of ultrasound.
Medical Instrumentation II
i ) Down stream ( = Blood flow direction)
ii ) Up stream ( = Blood flow reverse direction)
cosuc
DtD
coscos uc
D
uc
Dttt DU
cosuc
DtU
2222
cos2
cos
cos2
C
Du
uc
Du
Because… C >> ucosφ
Conclusion :
Continuous Doppler Flowmeter
Medical Instrumentation II
u
c
u
f
f
o
d
cff d
cfo
Doppler frequency shift
Ex) aviation, ship, submarine…
Medical Instrumentation II
Pulsed Doppler Flowmeter
D
1u2u
3u2u
1u
12321 uuuuu
Flow profile measuremen
t
Thermal Convection Flowmeter
Medical Instrumentation II
Thermister
f
2T
1T
i ) Bias current -> Thermister heatingii ) T₂Thermister is cooled by thermal convection
Weak Point : Invasive and Probe position is difficult.
Medical Instrumentation II
-> Volume, blood flow measurement
V
`i Howland Current
Source
Cuff
Artery openVein close
mmHg60
3. Plethysmography
Medical Instrumentation II
t
Z)(v
Venous Thrombosis
NormalVolume
Cuff On Cuff Out
Slope = flow
Arterial
Patient monitoring (Respiration monitoring)
Part II. Pulmonary Function Test
Medical Instrumentation II
1. ArchitectureTrachea
Bronchus
Alveoli
Area TT Au ,
AA Au ,
AATT AuAuQ
A
TTA A
Auu
TA uu 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 measurementDifferential pressure transducer
1P 2P
Diaphragm
i )
ii )1P 2P
Diaphragm
2C1C
1x 2x
Medical Instrumentation II
iii )
Mesh screen
1P 2P
Differential pressure sensor
Q
Flow
Mouth
RQPP 21
R
PPQ 21 Conclusio
n :
Airpump
Medical Instrumentation II
Ballon sensorHole Ballon
Gas
Pressure sensor
Pv5
MPiv
Control
Pressure
Metal switch
Switch On ->Switch Off ->
v0v5
iPP iPP
Medical Instrumentation II
5. Flow measurement
• Rotating Vane• Ultrasound Flowmeter• Thermal Convection Flowmeter• Pneumotachometer (standard)
Medical Instrumentation II
6. Volume measurement-> Plethysmography
t
TLC
FRC
RV
TV (Tidal Volume)
ERC
IC VC
Weak Point : It is Relative value, not absolute value.
Medical Instrumentation II
Water Spirometer
Water
Air
Pen
Rotating Paper
Mouth
CO₂ absorber
Medical Instrumentation II
Dry Spirometer
Air (gas)
Mouth
Inspiratory gas
Expiratory gas
Valve
Piston
Gas is Separated by two section
Medical Instrumentation II
7. FRC measurementHe dilution technique - patient at FRC
- prepare a spirometer of volume VSP and
initial He, concentration of fIHE
- patient breaths tooth spirometer - find He concentration of expiration F
SPFHeFHeIHe VFFFFRC
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.
2)(8.0 FNSP FVFRCFRC
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
He
He
CO
CO
I
F
F
I
B
ACO f
F
F
f
Pt
vD ln
)47(
60