CAN WEAK TURBULENCE GIVE HIGH-CONCENTRATIONS OF CARBON-DIOXIDE IN BABY CRIBS

The potential that Sudden Infant Death Syndrome (SIDS) is caused by ex pired air is examined by calculations of the diffusion of CO2 in a cri b, and considerations of the level of turbulence generated by room ven tilation and expiration. The calculations indicate a risk of CO2 accum ulation for a baby in prone position, when the diffusion coefficients in the room and the crib are smaller than 10(-3) m2 s-1, and the expir ed air is spread only over a part of the crib bottom. The calculations also indicate that the turbulence in the room may be below the critic al value of 10(-3) m2 s-1 when there is warmer air at ceiling height c ompared to the floor, and the area of the ventilation inlet is large, or the ventilation rate is low. There are indications that the turbule nce generated by the breathing may be smaller than the critical value when the infant is breathing through an open mouth, if the expired air is cooled to room temperature, and if the expiration rate is limited to about 3 times the normal value.