Ventilatory response to isocapnic hypoxia in parents of victims of sudden infant death syndrome.

Ventilatory response to progressive isocapnic hypoxia was measured in 14 parents of victims of sudden infant death syndrome (SIDS) and 12 matched control parents. Controls had a value for a measure of ventilatory responsiveness (parameter A) of 200.8 +/- 46.4, while SIDS parents had a significantly lower value of 64.4 +/- 16.2 (P less than 0.01). Since degree of hypoxic ventilatory drive is a hereditary characteristic, it is concluded that a relatively low ventilatory responsiveness to hypoxia might have been present in the SIDS victims.