MEDICAL INSTRUMENTATION 8 th 2005200444 Chapter 9 Respiratory

MEDICAL INSTRUMENTATION 8 th 2005200444 정진웅

Chapter. 9 Respiratory System Measurement

Respiratory System Measurement From now on, we focus on two subject - PFT : pulmonary function test - Patient monitoring(Respiration monitoring)

Respiratory System Measurement ( Architecture ) trachea velocit y bronchi a airflow alveolar O 2 and CO 2 diffusion at alveolar cross section area

Respiratory System Measurement ◎ physiological function - O 2 transport into blood stream - CO 2 removed from blood stream - Homeostasis of ph, partial pressure of O 2, partial pressure of CO 2 Ventilatory mechanics ⇒ RC equivalent circuit model ◎ Respiration Gas transport ⇒ Mass balance equation (Diffusion process)

Respiratory System Measurement ◎ Pressure measurement ① Differential Pressure transducer Diaphragm P 2 P 1 x 1 Strain gage x 2 C A C 1 B C 2

Respiratory System Measurement ② Balloon sensor hole gas pressure sensor (balloon) 5 V force pressure (P) metal switch 0 V : switch on P > Pi or, 5 V : switch off P < Pi resistor V 1 air pump force pressure (P) control

Respiratory System Measurement ◎ Flow measurement ① Rotating vane ② Ultrasound flow-meter ③ Thermal convection flow-meter ④ Prieumotachometer

Respiratory System Measurement P 1 P 2 Diff pressure sensor Q(flow) mesh screen measurement using with a injector resistance(fixed) mouth

Respiratory System Measurement ◎ Volume measurement (plethysmography)

Respiratory System Measurement ① water spirometer air water mouth CO 2 absorber

Respiratory System Measurement ② dry spirometer mouth expiratory gas piston Inspiratory gas valve

Respiratory System Measurement ◎ FRC measurement ① Helium dilution technique - Patient at FRC - Prepare a spirometer of volume VSP and initial He concentration of f. IHE - Patient brethes helium the spirometer - Find helium contradiction of expiration gas f. FHE

Respiratory System Measurement “ Equation of mass balance ”

Respiratory System Measurement ② N 2 washout technique - Patient at FRC - Prepare a spirometer with VSP , O 2 - Patient brethes to the spirometer - Measure N 2 concentration in the expiratory gas

Respiratory System Measurement ◎ Gas concentration measurement ① Mass spectroswophy ② Gas chromatography ③ Infrared spectroswophy ④ Raman spectroswophy ⑤ Emission spectroswophy ⑥ Paramagnetic O 2 analyzer

Respiratory System Measurement ◎ Gas transport measurement ① Gas distribution test ⇒ single N 2 breathe washout - RC → TLC O 2 inspiration - Pause (Hold breath) - Expiration and measure FN 2

Respiratory System Measurement ② Diffusion ⇒ CO diffusion capacity - Inspire CO, He, in air to TLC ( FICO , FIHe ) - Hold breath for 10 sec. - Expire to measure FFCO and FFHe CO diffusion capacity

THANKS!