Influence of high altitude on sudden infant death syndrome

Approximately 8,000 infants die annually in the United States of sudden infant death syndrome (SIDS), but the pathophysiology of events leading to death remains unclear. A number of the postmortem findings in these children are consistent with chronic and/or recurrent hypoxemia prior to death. Hypoxia may initiate factors or be the result of mechanisms that ultimately lead to death.1 Baker and McGinty2 reported that, in kittens, chronic, intermittent hypoxia can produce cardiorespiratory irregularity and depression and decreased active sleep, the latter being the sleep state when ventilation is least vulnerable to hypoxia. Naeye3 documented the presence of increased muscle mass in the small pulmonary arteries of infants living at high altitudes and those dying of SIDS at sea level.