What is SIDS?
Triple Risk Model
According to the Triple Risk Model,9,10,11,12 SIDS can occur when three elements come together: an infants critical development period, a vulnerable infant and exogenous stressors.
The critical development period encompasses the rapid growth phases that occur during an infants first 6 months of life, considered to be a time of vast physiological change and instability for an infants system. During this developmental period, changes occur in homeostatic controls such as sleeping and waking, breathing, heart rate, blood pressure and temperature.
The vulnerable infant represents an infant with an underlying defect or abnormality. In this model, normal infants do not die of SIDS. Instead, there are pathophysiological reasons behind these seemingly sudden deaths such as defects of the brain that control respiration, heart rate or cardiac function.
Finally, exogenous stressors are external or environmental challenges that a normal infant can overcome and survive but an already-vulnerable infant might not. These stressors include the risk factors such as prone sleep position, loose and soft bedding, secondhand tobacco smoke exposure or an upper respiratory infection.