Rebreathing expired gases from bedding: a cause of cot death?
The reported association of cot death and sleeping prone could be due to rebreathing of expired gases. A mechanical model simulating the respiratory system of an infant, exhaling warm humidified air with an end tidal carbon dioxide of 5%, has been used to investigate this. Some commonly used bedding materials caused an accumulation of carbon dioxide of 7% to over 10% with the model lying face down. This phenomenon persisted even with the head inclined at 45 degrees, but only on very soft materials, and could be a cause of cot death in a baby unresponsive to asphyxial blood gas changes. A coir fibre mattress allowed complete dispersal of exhalate as did a rubber sheet between any mattress and the covering sheet.
Bolton
D P
DP
Department of Physiology, University of Otago Medical School, Dunedin, New Zealand.
Taylor
B J
BJ
Campbell
A J
AJ
Galland
B C
BC
Cresswell
C
C
D001237:Asphyxia / Q000150:complications*; D001512:Bedding and Linens; D003625:Data Collection / Q000379:methods; D006801:Humans; D007223:Infant; D008954:Models, Biological; D016684:Prone Position; D012119:Respiration / Q000502:physiology*; D013398:Sudden Infant Death / Q000209:etiology*