Objective. 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. Methods
. Waveforms of respiration and heart rate trend were available for fiv
e infants; an alarm log only was available for the sixth. These printo
uts were reviewed with attention to mechanism and time to death. Resul
ts. All infants were born prematurely; autopsies reported the cause of
death as sudden infant death syndrome in three cases and bronchopulmo
nary dysplasia in the others. Bradycardia, which played a more promine
nt 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 wit
hin 20 minutes, whereas one death due to sudden infant death syndrome
was prolonged. Conclusion. Bradycardia is an important feature in all
six of these infant deaths. Although its etiology is unknown, hypoxemi
a or obstructive apnea may precede bradycardia. Home monitors equipped
to detect these possible antecedents will yield further insight into
sudden infant death.