Attenuated Responses to CO2 and Hypoxia in Parents of Threatened Sudden Infant Death Syndrome Infants

Ventilatory and heart rate responses to hypercapnia and hypoxia were measured in the following three groups: group I, controls (n=15); group II, parents of threatened sudden infant death syndrome (SIDS) infants (n=10); and group III, parents of SIDS infants (n=17). We found significantly reduced heart rate responses to carbon dioxide and hypoxia in group II (1.4 ± 1.9 percent and 16.0 ± 4.0 percent; mean ± SEM) compared with controls (7.1 ± 1.4 percent and 26 ± 2.4 percent; P < .025). Ventilatory responses to hypoxia in groups II and III were not significantly different from controls. Two group II mothers had a greatly reduced ventilatory response to carbon dioxide. Four other parents in group II had abnormally low heart rate responses to hypoxia or carbon dioxide. We concluded that parents of threatened SIDS infants have reduced heart rate responses to carbon dioxide and hypoxia and may have reduced ventilatory responses to carbon dioxide.