2007 Fiscal Year Final Research Report Summary
Damage Analysis by Elongation of Blood Vessels
| Project/Area Number |
17390198
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Legal medicine
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| Research Institution | Tohoku University |
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Principal Investigator |
FUNAYAMA Masato Tohoku University, Tohoku University Graduate School of Medicine, Professor (40190128)
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| Co-Investigator(Kenkyū-buntansha) |
KANETAKE Jun Tohoku University Graduate School of Medicine, 大学院・医学系研究科, Associate professor (90326661)
SAKAI Jun Tohoku University Graduate School of Medicine, 大学院・医学系研究科, Assistant professor (20431504)
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| Project Period (FY) |
2005 – 2007
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| Keywords | bedding / mathematical evaluation / rebreathing / respiratory simulation / sudden infant death |
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| Research Abstract |
This study used a mechanical simulation model to establish the relationship between types of bedding and rebreathing potential for an infant placed prone (face down) at different postnatal ages. The infant mannequin was connected to a respirator set to deliver physiologically appropriate combinations of tidal volume (V_T) and respiratory rates (RR) across a range of postnatal ages (0 to 18 months). Before measurements were made, CO_2 flow was regulated to 5%±0.1% of end-tidal PCO_2 (EtCO_2). After the model was placed in a prone position, any increase in the fractional concentration of inspired CO_2 (FiCO_2) was measured. FiCO_2 increased immediately and rapidly, and reached a maximum value within a few minutes. The maximum FiCO_2 ranged from under 2% to over 10%, depending on the bedding. FiCO_2 was also affected by V_T and RR. This model is not applicable to actual infants because of the large tissue stores of CO_2 in infants; however, it is useful for evaluation of gas diffusibility of bedding and will simplify the investigation of sleeping environments when a baby is found dead with its face covered by soft bedding. In general, the higher the FiCO_2, the greater the rebreathing potential. Theoretically, considering the paucity of body stores of O_2, changes in FiO_2 would be affected not by changes in FiCO_2, but by CO_2 production and gas movement around the infant's face. The rapid decrease of FiO_2 is approximated at the inverse of the FiCO_2 timecourse, suggesting the significance of not only CO_2 accumulation but also O_2 deprivation in the potential space around the baby's face.
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