Sudden Infant Death Syndrome
Sudden infant death syndrome (SIDS) is a mysterious phenomena that has managed to confound science so far. SIDS is defined as the sudden death of any infant or young child that is unexpected by history and in which a thorough post mortem examination fails to demonstrate an adequate cause (Hunt & Brouillette, 1987). It is the leading cause of death in infants in developed countries occurring at a rate of almost 2 per 1000 births. It most often occurs in infants between the ages of one month and eight months with the highest occurrence in the 4-6 month range. Several behaviors have been associated with this syndrome such as prolonged sleep apnea, increased risk of breath inspiration pause, excessive periodic breathing, diminished ventilatory sensitivity to hypoxia, and impaired arousal response to hypoxia, but none of these have stood out as the definitive cause or as a screening device (Hunt & Brouillette, 1987). Instead it appears SIDS may be the result of a collection of factors that in the right circumstances results in infant death. This paper will examine some of the factors that appear to be associated with SIDS as well as some hypotheses on the cause.
Recent findings have shown that one cause of what has been labeled SIDS is suffocation or carbon dioxide rebreathing (Kemp et al, 1993). Technically this is not SIDS but it is often misdiagnosed as the cause of death if the physical scene is not examined, and it may also be a significant cause of SIDS. It seems that the practice of placing infants in the prone position, common in America and Europe, may be detrimental to the infant’s well-being. Studies of rabbits placed in this position on various surfaces have shown death to ensue as a result of expired air becoming trapped creating a rebreathing scenario, suffocating the animal (Ponsonby et al, 1993). The study also found that the type of surface contributed to this result with soft and natural fiber mattresses having higher incidence of suffocation than firm synthetic ones. These findings do not find a solution but do provide information on how some deaths attributed to SIDS may have been prevented by placing these infants on their sides or backs. It also raises the question as to why the infants do not arouse from the hypoxic state created, or react as is normal in older children and adults.
One hypothesis that for a long time received much focus, was that SIDS was the result of recurrent apneic episodes. Today this idea has been rejected as the main cause, as many infant’s first apneic experience results in death and many that experience frequent apneic episodes never die. Still it can not be eliminated as it is most likely an associated factor with SIDS, that in unison with others results in death.
The leading mechanism that is being examined now is the failure to arouse. Arousal from sleep is in all likelihood the most important defense mechanism against danger stimuli such as hypoxia or...