Gas dispersal potential of infant bedding of sudden death cases. (I): CO₂ accumulation around the face of infant mannequin model

We assessed CO₂ gas dispersal potential of bedding that had actually been used by 26 infants diagnosed with sudden unexpected infant death using a baby mannequin model. The age of victims ranged from 1 to 12 months. In some cases, the parents alleged that the infant faces were not covered with bedding when they were found. The parent's memories, however, may not have been accurate; therefore, we examined the potential for gas dispersal based on the supposition that the bedding had covered their faces. The mannequin was connected with a respirator set on the tidal volume and respiratory rates matched with the baby's age. Before measuring, CO₂ flow was regulated in 5% ± 0.1% of end-tidal PCO₂. After the model was placed on each bedding condition, measurements were performed at least five times under each respiratory condition. Four cases showed a plateau of FiCO₂ <4.8%, 15 were 4.8-12%, and the other seven were 12% or more, when they reached a plateau. Of course, our model does not take large tissue stores of CO₂ into account. However, our model could show the potential gas dispersal ability of bedding. Especially, the latter seven bedding could have high rebreathing potential if they covered the infant's faces and the probability of environmental asphyxia should be considered.