1987 Fiscal Year Final Research Report Summary
The development of CO_2 controller
| Project/Area Number |
61870060
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| Research Category |
Grant-in-Aid for Developmental Scientific Research
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| Allocation Type | Single-year Grants |
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| Research Field |
麻酔学
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| Research Institution | UNIVERSITY OF TOKYO |
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Principal Investigator |
OGURA Makoto Department of Anesthesiology, University of Tokyo Faculty of Medicine, 医学部(病), 助手 (50185568)
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| Co-Investigator(Kenkyū-buntansha) |
YASUMOTO Kazumasa Department of Anesthesiology, Showa University Faculty of Medicine, 医学部, 助教授 (90054030)
AKAGI Takako Department of Anesthersiology, University of Tokyo Faculty of Medicine, 医学部(病), 助手 (50184073)
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| Project Period (FY) |
1986 – 1987
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| Keywords | CO_2 controller / integral control / 動脈血炭酸ガス分圧 / 終末呼気炭酸ガス / 積分動作 / 比例動作 |
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| Research Abstract |
We devised a tidal volume controller which could antomatically obtain the pro-set end tidal CO_2 (ETCO_2 ) concentration. The controller had an A/D and a D/A converter to determine the TTCO_2 and to adjust Vt without using a computer. Shile using the controller, a Servo ventilator 900 C and Servo 930 CO_2 analyzer (or Perkin Eler Medical Gas Analyzer) were used as a respirator and an equipment to detemine the concentration of ETCO_2 (or PaCO_2). And the CO_2 contoroller can manage ETCO_2 using 2 control methods such as proportional control and integral control.
We compared two control methods to devise a useful control system for obtaining and maimtaining pre-set CO_2 level under general ansesthesia. Then we managed hypercapnia using the CO_2 contoroller.
1. The intensity of overshooting in the Vt was greater with increasing speed of changing V_T (SCV). The tendency was more conspicuous in control A than in cntrol B. The changes in the peak airway pressure while ETCO_2 was automatically controlled was similar to those in the V_t .
2. The faster the SCV was set, the shorter the response time was in both controls. At each setting, the response time was shorter under control A than under control B. The shortest settling time showed the necessary duration to obtain a stable preset ETCO_2, was 20.05 (+-)1.6 min in cotrol A and 21.6(+-) 0.9 min in control B.
3. There was no significant changes in cardiac output in the group while the controller decreased ETCO_2 by 4% with 1ml/sec/% SCV.
4. the results show that integral control is better than propertional control for controlling both ETCO2 and PaCO_2 automatically under artificaial ventilation and that SCV should be set below 20ml/sec. Because there was less effect in pleural pressure and in plasma catecolamine level, the CO_2 controller could safely improve hypercapnia with slow SCV (1ml/sec/%).
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