IMPAIRED VENTILATION IN INFANTS SLEEPING FACEDOWN - POTENTIAL SIGNIFICANCE FOR SUDDEN-INFANT-DEATH-SYNDROME

Although accidental suffocation has been suggested as a cause of sudde n infant death syndrome in infants who are found prone with their face s straight down, the occurrence and effects on breathing of this posit ion in living infants are unknown. We studied prone sleeping infants t o see whether they will sleep with their faces straight down; whether they can spontaneously change from this position; the way that thermal stimuli or bedding softness influences this change; and whether rebre athing or airway obstruction occurs. We studied 11 healthy infants, ag ed 0.2 to 6 months, while they slept on soft and on firm bedding. Most infants slept facedown spontaneously or when turned to this position. All could turn their heads readily but slept facedown for variable pe riods. All infants put their faces straight down more often after cold than after warm stimuli. Obstructive apnea occurred only once, but re breathing occurred in all subjects. When the infants were in the faced own position, inspired carbon dioxide was three times greater on soft than on hard bedding. End-tidal carbon dioxide partial pressure rose i n all subjects while they were in the facedown position; in one infant , high end-tidal carbon dioxide partial pressure and desaturation occu rred without signs of arousal. We conclude that infants sleeping faced own may occasionally have significant asphyxia; this sleep position ma y have a role in some infant deaths dia nosed os sudden infant death s yndrome.