Rebreathing of exhaled air is one proposed mechanism for the increased risk for sudden infant death syndrome among prone sleeping infants. We evaluated how carbon dioxide (CO2) dispersal was affected by a conventional crib mattress and 5 products recently marketed to prevent prone rebreathing.
Infant pulmonary laboratory.
An infant mannequin with its nares connected via tubing to an 100-mL reservoir filled with 5% CO2. The sleep surfaces studied included: firm mattress covered by a sheet, Bumpa Bed, Breathe Easy, Kid Safe/Baby Air, Halo Sleep System, and Sleep Guardian. The mannequin was positioned prone face-down or near-face-down. The sleep surfaces were studied with the covering sheet taut, covering sheet wrinkled, and with the mannequin arm positioned up, near the face.
We measured the fall in percentage end-tidal CO2 as the reservoir was ventilated with the piston pump. The half-time for CO2 dispersal (t1/2) is an index of the ability to cause or prevent rebreathing.
Compared with the face-to-side control, 5 of 6 surfaces allowed a significant increase in t1/2 in all 3 prone scenarios. The firm mattress and 4 of the 5 surfaces designed to prevent rebreathing consistently allowed t1/2 above thresholds for the onset of CO2 retention and lethal rebreathing in an animal model (J Appl Physiol. 1995;78:740).
With very few exceptions, infants should be placed supine for sleep. For infants placed prone or rolling to the prone position, significant rebreathing of exhaled air would be likely on all surfaces studied, except one.