Ventilatory Control in Parents of Victims of Sudden-Infant-Death Syndrome

Since a defective ventilatory-control mechanism may have a role in the sudden-infant-death syndrome (SIDS), and hereditary factors influence the degree of ventilatory drive, we measured ventilatory responsiveness to carbon dioxide with and without increased airway resistance in 12 parents of SIDS victims and 12 control parents matched for age and size. Ventilatory response (ΔV̇₁/ΔPCO₂) and “respiratory drive” (ΔP₁₀₀/ΔPCO₂) were measured both with and without added resistance to inspiratory flow. SIDS parents had significantly lower ventilatory response with added resistance (P<0.05) and without it (P<0.01) and significantly lower respiratory drive with added resistance (P<0.001) and without it (P<0.05). Control parents had significantly increased respiratory drive when the resistance was added (P<0.005), whereas SIDS parents did not. The data suggest that a low ventilatory response to carbon dioxide and a diminished compensatory response to increased airway resistance may increase a potential parent's risk of having a child susceptible to SIDS. (N Engl J Med. 1980; 302:486–491.) Sudden-infant-death syndrome (SIDS) is a poorly understood phenomenon characterized by the unexplained and unexpected death of apparently healthy infants from one month to one year of age. Although over 100 hypotheses¹ on its underlying pathophysiologic mechanism have been postulated, strong evidence now suggests a primary respiratory event.^{2 3 4 5} Evidence for upper-airway obstruction^{1,6 7 8} and for a defective ventilatory-control mechanism^{9 8 10 11} have been presented as explanations. It has been shown that there are familial tendencies in the magnitude of chemical ventilatory drive.^{12 13 14 15} It is also known that the syndrome^6,16 and “near-misses” (infants found apneic and resuscitated by their parents) may be found in familial.