Cardiorespiratory recordings from infants dying suddenly and unexpectedly at home

Little is known about the mechanism of death during sudden infant death. To study the mechanism, we obtained data on six infants who died while on a memory-equipped cardiorespiratory monitor.

Waveforms of respiration and heart rate trend were available for five infants; an alarm log only was available for the sixth. These printouts were reviewed with attention to mechanism and time to death.

All infants were born prematurely; autopsies reported the cause of death as sudden infant death syndrome in three cases and bronchopulmonary dysplasia in the others. Bradycardia, which played a more prominent role than central apnea, was preceded by tachycardia in two deaths. Resuscitation occurred within 1 minute in four cases; no response to alarms occurred in the other two cases, apparently because the parents were desensitized by prior meaningless alarms. Five patients died within 20 minutes, whereas one death due to sudden infant death syndrome was prolonged.

Bradycardia is an important feature in all six of these infant deaths. Although its etiology is unknown, hypoxemia or obstructive apnea may precede bradycardia. Home monitors equipped to detect these possible antecedents will yield further insight into sudden infant death.