| Co-Investigator(Kenkyū-buntansha) |
YODA Takashi St.Marianna University of Medicine, Dept.of Pediatrics, Lecturer, 医学部, 講師 (50220752)
HAYAKAWA Hideyuki St.Marianna University of Medicine, Dept.of Legal Medicine, assistant, 医学部, 助手 (10373052)
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| Budget Amount *help |
¥2,800,000 (Direct Cost: ¥2,800,000)
Fiscal Year 2005: ¥1,000,000 (Direct Cost: ¥1,000,000)
Fiscal Year 2004: ¥1,800,000 (Direct Cost: ¥1,800,000)
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| Research Abstract |
An animal experiment was conducted to investigate whether covering both nose and mouth by bedding may cause lethal hypoxemia in healthy infants.
[Methods]
A mask of a dead infant was made of polyurethane resin, and a vertical load of 1.5 kg was added. An endotracheal tube was placed in a piglet and linked to the nasal cavity of the mask, through which the piglet breathed. Blood pressure (BP), heart rate (HR), arterial oxygen saturation (O_2sat), respiratory rate (RR), expired air oxygen concentration (exO_2) and expired air carbon dioxide concentration (exCO_2) were monitored continuously, and arterial oxygen concentration (PaO_2) and arterial carbon dioxide concentration (PaCO_2) were monitored as necessary. For bedding, soft and hard Japanese beds (futons) and a mattress dedicated for prone sleeping were used.
[Results]
1.When the mask was placed in a face-down position on the soft futon, the animal immediately started forced inspiration. O_2sat and exO_2 quickly decreased within three minutes, and PaO_2 decreased to 29.8 mmHg three minutes later. When the mask was placed in a face-up position three minutes later, respiratory condition and all test values quickly returned to normal.
2.When the mask was correspondingly placed on the hard futon, PaO_2 gradually decreased to 44.2 mmHg five minutes later, 30.1 mmHg 25 minutes later and 31.0 mmHg 35 minutes later. O_2sat and exO_2 also gradually decreased, and the animal died 50 minutes later.
3.When the mask was correspondingly placed on the mattress dedicated for prone sleeping, PaO_2 decreased to 36 mmHg five minutes later. O_2sat and exO_2 quickly decreased for the first three minutes and thereafter decreased as gradually as BP, HR and RR did, and the animal died 25 minutes later.
[Conclusion]
These findings suggest that infants may quickly die from hypoxemia caused by both nose and mouth being covered by bedding while they sleep in a prone position, especially in a face-down position.
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