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Contents Cardiac Output - Fick
- Indicator Dilution - Thermo Dilution
Electromagnetic flow meter Ultrasound flow meter - Transit time
- Continuous Doppla - Pulsed Doppla - Thermal Convection
Plethysmography
Indicator Dilution and Fick Method
FiCi
FoCo
dt
dm
F : flow C : concentrationThe unit of blood flow : l/min or ml/s
(infusion rate)
Mass Balance Equation
FCdt
dmFC oi
The quantity of in and out is the same,and there is no leakage.
io CCdtdm
F
# Indicator Dilution
# Fickdt
dm: O2 consumption, L/min ( measured by spirometer)
Ci = Cv : concentration in vein
Co = Ca : concentration in artery
io CCdtdm
F
Indicator Dilution ( Dye dilution Method)
Use Cardio green or Indocyannine green for a dye.
t
c(t)
bolusinjection
indicator dilution curve
TExtrapolation
recirculation
FtCdt
dvtC
dt
dmdvtCdmtC
dv
dm )()( ,)( ),(
mdttCFdm
dtFtCdmTT
00)(
)(
T
dttC
mF
0)(
Thermo-dilution
t
c(t)
bolusinjection
T
Use cold saline(4˚C)
]/[)(
3
0
1sm
dttTc
QF t
bbb
K][J/kg blood, ofheat specific
][kg/m density, blood
[J] injectate, ofcontent heat 3
b
b
iiii
c
cTVQ
Transit time flowmeter
θD
μc
velocity of RBC, WBC and platelit
velocity of ultra sound (1) down-stream
cosc
Dtd
(2) up-stream
cosc
Dtu
2222
cos2
cos
cos2
coscos
c
D
c
D
c
D
c
Dttt du
)cos( 222 c
Doppler flowmeter(1) Continuous Doppler flowmeter
(cf) Radar system
objectfo, c
f+fd, c usmc /103 8 c
u
f
f
o
d
(2) Pulsed Doppler flowmeter
u1
u1u2
u2u3
t
Tfd1fd1
fd2fd2
fd3
x
f
Thermal convection flowmeter
F
T2
Thermister
(1) Bios current => Thermister heating(2) T2 Thermister is cooled by thermal convection.
Invasive, probe positioning is difficult.The stronger F gets, The sharper the temperature of T2
is decreased.
(cf.) respiratory monitoring by thermister
Temp. of inspiration is 25˚C.Temp. of expiration is 36.5˚C.
Plethysmography
iVcuffleg toes
open arteryclose vein
)( flowfdt
dv
Z(V)
tcuff cuff off
slope= flow(in artery)
slope= flow(in vein)
normal
VenousThrombosis
Respiratory System
# Architecture
Tracher
Bronchas
…
Alveoli
uT
uA
AT
AA
AATT AuAuQ air flow
velocity
cross-sectional area
[l/min or ml/s]
The total of volume flow is not changed.
TA
TTA uA
Auu velocity of the air
at alveoli is almost zero.
# Physiological functions- O2 transport into blood stream- CO2 removal from blood stream- Homeostasis of PH, PO2, PCO2
# Respiration
- Ventilatory mechanics => RC equivalent circuit model- Gas transport => Mass balance equation (Diffusion process)
Pressure measurement(1) Differential pressure transducer
diaphragm
P1 P2
diaphragm
strain gage
(2) Balloon Sensor
gas
hole
ballonP pressure
sensorair
pump
MPP Pi
metal switch
Vi
control
pressure (Pi)
+5V0V : switch on => P>Pi5V : switch off => P<Pi
Flow measurement(1) Rotating vane(2) Ultrasound flowmeter(3) Thermal convection(4) Pneumotachometer
# Pneumotachometer
Q(flow)
P1 P2
mouth
mesh screen
QRPP 21
measurement resistance
)(21 nCalibratioR
PPQ
Volume measurement(1) Water spirometer
mouth
CO2
absorber
water
air
pen
single turn potentimeter
TLC
Rv
FRV
vital capacity
TV
IC
ERC
Vc
(2) Dry spirometermouth
inspirationgas
expiratorygas (empty)
valvepistol
change the position of the pistol during breathing.
FRC measurnment
(1) He Dilution technique - Patient at FRC - Prepare a spirometer of volume Vsp and imitial He Concentration of FIHe
- Patient breaths Fb the spirometer - Find He concentration of expiratory gas FIHe
spF
FI
IspIsp
VF
FFFRC
FFRCVFV
He
HeHe
HeHe
)(
FRC measurnment
(1) N2 washout technique - Patient at FRC - Prepare a spirometer with O2, Vsp - Patient breaths to the spirometer - Measure N2 concentration in the expiratory gas
2)(8.0
NFsp FVFRCFRC
Gas concentration measurement
(1) Mass spectroscophy(2) Gas chromatography(3) Infrared spectroscophy(4) Ramen spectroscophy(5) Emission spectroscophy(6) Paramagnetic O2 analyzer
Gas transport measurement(1) Gas distribution test => single breath N2 washout - RC => TLC O2 inspiration - pause (hold breath) - Expiration and measure FN2
(2) Diffusion test => CO diffusion capacity - Inspire CO, He in the air to TLC from RC - Hold breath for 10sec - Expire to measure FFCO and FFHE
]ln[)47(
60
He
He
CO
CO
I
F
F
I
B
ACO F
F
F
F
Pt
UD