1996 Fiscal Year Final Research Report Summary
Basic consideration of apnea test for brain-death determination
| Project/Area Number |
07557307
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| Research Category |
Grant-in-Aid for Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Section | 試験 |
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| Research Field |
Medical sociology
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| Research Institution | CHIBA UNIVERSITY |
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Principal Investigator |
FUKUDA Yasuichiro CHIBA UNIVERSITY,SCHOOL OF MEDICINE,PROFESSOR, 医学部, 教授 (10009649)
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| Co-Investigator(Kenkyū-buntansha) |
SUDO Tomoko CHIBA UNIVERSITY,SCHOOL OF MEDICINE,ASSISTANT, 医学部, 助手 (20272320)
HAYASHI Fumiaki CHIBA UNIVERSITY,SCHOOL OF MEDICINE,Lecturer, 医学部, 講師 (80173029)
NISHINO Takashi CHIBA UNIVERSITY,SCHOOL OF MEDICINE,PROFESSOR, 医学部, 教授 (80009703)
HIRASAWA Hiroyuki CHIBA UNIVERSITY,SCHOOL OF MEDICINE,PROFESSOR, 医学部, 教授 (80114320)
KURIYAMA Takayuki CHIBA UNIVERSITY,SCHOOL OF MEDICINE,PROFESSOR, 医学部, 教授 (20009723)
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| Project Period (FY) |
1995 – 1996
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| Keywords | Determination of brain death / Apnea-test / Respiratory rhythm / Recording of respiratory activity / Stylopharyngeal muscle activity / Respiratory stimulation / Negativ airway pressure |
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| Research Abstract |
The apnea test is one of important items for determination of brain-death. Conventional procedure is to confirm a complete lack of spontaneous respiratory movement by observation during cessation of resuscitatory artificial ventilation. The procedure is based on the assumption that accumulation of CO2 and hypoxia should stimulate the initiation of spontaneous respiratory movement if brain stem mechanism of respiratory center is kept intact. There is, however, critical arguments about the method of respiratory stimulation and determination of the lack of spontaneous respiratory activity. To overcome this drawbacks we proposed in the present study that the presence or lack of spontaneous respiratory activity should be confirmed by a more objective method such as recording electromyogram of respiratory muscle during respiratory stimulation with more reliable and sure methods. These problems were analyzed in the anesthetized-artificially ventilated rat. We found that among various respiratory neural outputs the inspiratory activity of glossopharyngeal nerve (stylopharyngeal muscle branch) exhibited the highest resistivity to respiratory depression and disappeared finally and appeared first during application of respiratory suppression and recovery. Since hypercapnia and/or hypoxia are not always reliable and safe respiratory stimulants, we tested application negative airway pressure during artificial ventilation. The lung deflation by negative airway pressure consistently stimulated respiratory rhythm generation even during respiratory arrest by ventral medullary surface cooling or hypocapnia. We conclude that the lack of spontaneous respiratory activity in the brain-death condition should be confirmed by absence of inspiratory activity in the stylopharyngeal muscle during application negative airway pressure ventillation which preserves normal CO2 and O2 partial pressure of patient.
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