Observations made on severe apneic spells in two infants at risk for sudden death.

We have studied the sequence of events during prolonged apneic spells in two infants who, by virtue of multiple risk factors or ultimate death, were at risk for sudden death. Using techniques to quantitate airflow and pharyngeal airway pressures, we have reported many descriptive aspects of the apnea in these infants. Specifically, we have noted that severe apneic spells in these infants were accompanied by a wide spectrum of lengths and types of shorter apneas. In the case of infant A, the most severe spells occurred in clusters. Physiologic phenomena usually considered normal (sighs, swallows, etc.) often occurred in association with the apneic spells. In addition, we found that: 1) mixed apnea was the clinically significant form of apnea; 2) in mixed apnea, the site of obstruction was in the pharynx; 3) obstruction often occurred at the beginning of the spells; and 4) this obstruction occurred progressively over a series of breaths prior to the spell and resolved in a similar fashion. Theophylline, in one infant, decreased the incidence of apnea.