8 th 2005200444 정진웅 medical instrumentation. chapter. 9 respiratory system measurement

8th 2005200444 정진웅

MEDICAL MEDICAL INSTRUMENTATIONINSTRUMENTATION

Chapter. 9Chapter. 9Respiratory System MeasurementRespiratory System Measurement

Respiratory System Measurement

From now on,From now on,

we focus on two subjectwe focus on two subject

- PFT : pulmonary function test- PFT : pulmonary function test

- Patient monitoring(Respiration - Patient monitoring(Respiration monitoring)monitoring)


( Architecture )

trachea

bronchia

alveolar

TT AU

AA AU

AATT AUAUQ

airflow

velocity

cross section

area

)/()min/( smlorl

A

TTA A

AUU

O2 and CO2 diffusion at alveolar


◎ ◎ physiological functionphysiological function

- O2 transport into blood stream

- CO2 removed from blood stream

- Homeostasis of ph, partial pressure of O2, partial pressure of CO2

Ventilatory mechanicsVentilatory mechanics ⇒ ⇒ RC equivalent circuit modelRC equivalent circuit model

Gas transportGas transport ⇒ ⇒ Mass balance equationMass balance equation (Diffusion process)(Diffusion process)

◎ ◎ RespirationRespiration


◎ ◎ Pressure measurementPressure measurement

① ① Differential Pressure transducerDifferential Pressure transducer

Strain gage

Diaphragm

x1 x2

P1P2

A B

C1 C2

C


② ② Balloon sensor Balloon sensor

pressure sensor

hole

(balloon)

gas

force pressure (P)

air pump

P

metal switch resistor

5V

V1

0V : switch on P > Pi

or,5V : switch off P < Pi

force pressure (P)control


◎ ◎ Flow measurementFlow measurement

① ① Rotating vaneRotating vane

② ② Ultrasound flow-meterUltrasound flow-meter

③ ③ Thermal convection flow-meterThermal convection flow-meter

④④ PrieumotachometerPrieumotachometer


P1 P2

Q(flow) mouthmesh screen

Diff pressuresensor

RQPP 21

R

PPQ 21

measurementusing with a injector

resistance(fixed)


◎ ◎ Volume measurement (plethysmography)Volume measurement (plethysmography)


① ① water spirometerwater spirometer

mouth

water

air

CO2 absorber


② ② dry spirometerdry spirometer

Inspiratorygas

expiratorygas

mouth

valve

piston


◎ ◎ FRC measurementFRC measurement

① ① Helium dilution techniqueHelium dilution technique

- Patient at FRC- Patient at FRC - Prepare a spirometer of volume V- Prepare a spirometer of volume VSPSP and and initial initial He He concentration of concentration of ffIHEIHE

- Patient brethes helium the spirometer- Patient brethes helium the spirometer

- Find helium contradiction of expiration gas - Find helium contradiction of expiration gas ffFHEFHE


FHESPIHESP FFRCVFV )(

“ Equation of mass balance ”

SPFHE

FHEIHE VF

FFFRC


② ② NN22 washout technique washout technique

- Patient at FRC- Patient at FRC - Prepare a spirometer with V- Prepare a spirometer with VSPSP , O , O22

- Patient brethes to the spirometer- Patient brethes to the spirometer

- Measure - Measure NN22 concentration in the expiratory gas concentration in the expiratory gas

2)(8.0

NFSP FVFRCFRC


◎ ◎ Gas concentration measurementGas concentration measurement

① ① Mass spectroswophyMass spectroswophy

② ② Gas chromatographyGas chromatography

③ ③ Infrared spectroswophyInfrared spectroswophy

④ ④ Raman spectroswophyRaman spectroswophy

⑤ ⑤ Emission spectroswophyEmission spectroswophy

⑥ ⑥ Paramagnetic Paramagnetic OO22 analyzeranalyzer


◎ ◎ Gas transport measurementGas transport measurement

① ① Gas distribution testGas distribution test ⇒ ⇒ single single NN2 2 breathe washoutbreathe washout

- RC → TLC - RC → TLC OO22 inspiration inspiration

- Pause (Hold breath)- Pause (Hold breath)

- Expiration and measure - Expiration and measure FFN2N2


② ② Diffusion Diffusion ⇒ ⇒ CO CO diffusion capacitydiffusion capacity

- Inspire CO, He, in air to TLC ( - Inspire CO, He, in air to TLC ( FFICO ,ICO , F FIHeIHe ) )

- Hold breath for 10sec.- Hold breath for 10sec.

- Expire to measure - Expire to measure FFFCO FCO and and FFFHeFHe

:)ln()47(

60

IHe

FHe

fCO

ICOCO f

F

F

f

Pt

VD

CO diffusioncapacity

THANKS!

8 th 2005200444 정진웅 medical instrumentation. chapter. 9 respiratory system measurement

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