358 EEG-SUPPRESSfON FOLLOWING AUGMENTED BREATHS DURING APNEA

Abstract

Towards elucidation of mechanisms in initiation and termination of apnea and occurance of bradycardia polygraphic recordings were performed to 10 preterm infants (mean gestational age 28.0 / range 26.1 to 32.1 weeks) at 36, 40, 44 and 52 weeks conceptional age including EEG, submental and diaphragmatic EMG, ECG, thoracal respiratory movements, nasal airflow, tcpO2 and tcpCO2. A total of 148 apneas (>10 sec.) were recorded. 33 of them were mixed/obstructive events in N-REM-sleep and 66 in REM-sleep. Apneas followed a sigh in 16 of 106 REM apneas and 29 of 43 N-REM apneas (20 of the N-REM apneas were mixed with the inactive part proceeding the obstructive part). A significant suppression of EEG-activity (Wilcoxon Rank, p<0.05) was found during mixed/obstructive N-REM apneas and inactive REM apneas. Moreover in N-REM-sleep a more distinct EEG-suppression, which was significant for the 8-13 Hz band (Wilcoxon, p<0.05), accompanied the apneas with an initial sigh in contrast to those without. Bradycardia occured in 13 N-REM apneas and in 11 REM apneas also with a preference of mixed apneas in both sleep-phases (CHI-square, p<0.005). A parallel occurance of initial sighs and bradycardia was found in 10 N-REM mixed apneas only.