PATTERN OF SUBMENTAL AND DIAPHRAGMATIC MUSCLE ACTIVITY DURING MIXED AND OBSTRUCTIVE APNEA

Abstract

For characterization of mixed and obstructive apnea persisting in infants after severe IRDS we obtained polygraphic recordings incl. submental and diaphragmatic EMG by surface electrodes in 2 wks intervals from 40-46 and at 52 wks postconc ageRESULTS: Pt 40 wks mixed apnea was found to be the predominant type of apnea with preponderance in NON-REM sleep decreasing in number towards 52 wks. 80% of these events had the sequence; inactive-obstructive and were almost regularly characterized by the following EMG pattern: In 80% the inactive part was initiated by a sigh with simultaneous phasic increase of both submental and diaphragma EMG. The following obstructive component showed in 54% a rhythmic diaphragma activity with a short phasic activation of the submental EMG which, however, did not terminate the apnea. Only a synchronous phasic activation of both submental and diaphragma EMG (likely to reflect active exspiration) resolved airway obstruction. Arousal didn't occur. Bradycardia frequently accompanied the obstruction and in one mixed apnea with hypoxemia the synchronous EMG activation was lacking and asystoly occurred which could be terminated by atactile stimulation alone.CONCLUSION: Mixed apnea often accompanied by bradycardia present a regular pattern of synchronicity of submental and diaphragmatic muscle activation for terminating the apnea. Hypoxemia might be responsible for disturbing this synchronicity and thus leading to life threatening events.