Patterns of EEG frequency, movement, heart rate, and oxygenation after isolated short apneas in infants

Patterns of events occurring at the end of apneas have rarely been reported in infants. No previous studies have compared these patterns to those of s pontaneous events during sleep. We examined 163 isolated apneas in 17 infan ts (47 +/- 4 wk postconceptional age) who underwent polysomnography for sus pected upper airway problems. Mean apnea duration was 6.5 +/- 1.5 s (range, 5 to 11.5 a). 78% of apneas occurred in active sleep, and 67% of apneas we re obstructive. We recorded the occurrence of body movement or augmented br eath and analyzed changes in EEG frequency greater than or equal to 1 s, he art rate, and oxygen saturation value at the end of apneas and of a control ventilatory period defined as a period of breathing equal in duration to t he apnea and preceding the apnea by 1 min. We found that 7.9% of apneas and 11.6% of control periods were followed by an augmented breath and that 14. 1% of apneas and 0.5% of control periods were followed by a body movement. The percentages of motor events or no event differed significantly after th e apneas (p = 0.008) compared with the control periods. A significant incre ase in EEG frequency was observed at the end of the apneas compared with th e control periods (p < 0.04). EEG frequency increased after 61% of the apne as. Neither heart rate nor oxygen saturation value changed after the contro l periods. Heart rate decreased significantly after the apneas not followed by a motor event (p = 0.02) but not after the apneas followed by a body mo vement. We conclude that 1) at termination of isolated apneas in infants, a motor event was rare, whereas an EEG frequency increase was common; 2) eve nt patterns at apnea termination differed from those at control period term ination.