ol. 6, No.3 7/(7) IU UNGOO ontrol Engineering for Development of a Mechanical entilator for IU Use Spontaneous Breathing ung Simulator UNGOO Kenji OZAKI*yoji IIDA*Kazutoshi SOGA* and Yasuhiro UENO* A lung simulator UNGOO is developed for the purpose of simulating ventilation dynamics in a spontaneous breathing especially for checking performances of mechanical ventilator with several assist modes including proportional assist mode. It is possible to simulate (net pressure generated by respiratory muscles), (resistance) and (compliance) with mathematical model of ventilation dynamics. It is composed of a high speed digital servo system and bellows pump with a servo-motor and can simulate dynamics near to patient s lung and/or respiratory system. It is also possible to simulate the change of lung function with various condition of patient, so it can be applied for systematical testing for several types of mechanical ventilators. In this paper, verification results of, and dynamic characteristics are reported, and also it is evaluated as good enough for an actual usage. Key Wordslung simulator, respiratory muscles, airway resistance, lung compliance, digital control [] UNGOO UNGOO [ ] F * * Air Water Safety Services Inc. (eceived August 7, 6).. a) b) c) Fig. (a) P AW P A QAW = ( PAW PA ) () (b) (G ) dg = γ Q () AW dt γ () () PA = G D T D cmh O (-) d( PA ) = Q (-) AW dt = T = γ P D A P A 7
(c) d d M D = PA PMUS (3) dt dt A M D D A A ol. 6, No.3 7/(7) (),(-),(3) Fig. (3) ()(-) (), P( ) P P A D & s P A P A P AW P A Fig. Block diagram of espiratory system P AW airway pressure ;[cmh O] P A alveolar pressure ;[cmh O] net pressure generated by respiratory muscles ;[cmh O] volume ;[ml] quantity of airway flow ;[/min] equivalent mass of the lung ;[cmh O*sec /ml] D equivalent dumping of the lung ;[cmh O*sec/ml] E elastance ;[cmh O/m]= / compliance of the lung ;[ml/cmh O] air away resistance ;[cmh O//sec] G aerial gravity ;[g] γ aerial specific gravity ;[g*min/] D aerial invariable A area of bellows pump(cylinder) ;[cm ] T default value of temperature ;[] P A default value of alveolar pressure ;[ cmh O] Servo servomechanism (servo amplifier/servo motor/ball screw) Fig. =cmh O =7.5cmH O//sec =5m/cmH O(P AW )= ( )=5m Fig.3 (P A ) ( )P A = () (/ ) ( =) P A (3) D () (M)=5g(D)(3) Fig. Schematic configuration of the respiratory system 8
ol. 6, No.3 7/(7) Pmus cmho Qaw it/min 8 6 4 4 6 4 - -4 4 6 time sec mit Palv cmho 5-5 4 6 9 8 7 6 5 4 6 time sec Fig.3 Wave data of the patient 3. 3. (P AW )(P A ) Fig.4 Fig.4 Hardware of UNGOO 3. 55Hz A 7 5msec cmh O (Honeywell )bit AD.3 cmh O 3.3 A B A B () A Fig.5 A Software P AW outside P A Servo Bellows Pump mechanism D & P A output to ventilator s P A Mass balance of Bellows Pump interface Fig.5 Block diagram of a circuit A Fig. () (P A ) A Fig.3 () B Fig.6 B Software P AW P A Servo Bellows Pump mechanism D & s output to ventilator = & ( ) Fig.6 Block diagram of a circuit B interface 9
ol. 6, No.3 7/(7) A() (P AW )P A (-)(-) dpa d = QAW (-) dt dt = P A P AW ( & ) ( ) 4. Table Item ange Unit olume 34 ml Flow 33 /min Pressure cmh O ompliance ml/cmh O esistance 35 cmh O//sec Table Specification 4. A B Fig.7 A P AW P A 4. P P Q AW A = (4) AW B P A P A P AW (4) P Q A = PAW AW (5) Measure [cmho//sec] 5 45 4 35 3 5 5 5 (circuit B) (circuit A) 5 5 5 3 35 4 45 5 riterion [cmh O//sec] Fig.7 omparison data of resistance JIS T 74-989 3) A B =5[cmH O//sec] 9 4.3 A B Fig.8 A ( =) P A (6) B ( =) (6) = (6) P A
ol. 6, No.3 7/(7) 8 Measure [ml/cmh O] 8 6 4 Method A Method B 4 6 8 riterion [ml/cmh O] Fig.8 omparison data of compliance JIST 74-989 3) 5 A 3.6 B.4 Flow [/min] Flow [/min] 6 4 8 6 4 (measurement) (theoretical) = 5 = 7.5() 5 5 Time [msec] Fig.9 esponse (by circuit A) (theoretical) (measurement) =5 =7.5( ) =5 =7.5( ) 8 4 8 4 Pressure [cmho] Pressure [cmho] 4.4 Fig.9Fig. A B =[cmh O] Fig.3 =D = A B 5[msec] B P A A 5[msec] 5 5 Time [msec] Fig. esponse (by circuit B) 5. 5. Fig. Fig.ompartment Model Fig.6
5. () 4[cmH O].[sec] () 45[cmH O].3[5sec] 5.3 Feedback O hemical Feedback ) 6. A B, [], PS(Pressure Support entilation) SIM(Spontaneous Intermittent Mandatory entilation) PA(Proportional Assist entilation) ) J. M. B. Hughes and N. B. Pride, (), () 3) JIS T 74-989 ol. 6, No.3 7/(7) [ ] 97 6 SIE, ISIE