Deglutition and respiratory patterns during sleep in the aged with OSAS

Clearance of the pharynx by deglutition, which removes matter that could be aspirated, is important in protecting the airways and lungs against aspiration. The deglutition and respiratory phase patterns during sleep in the aged with obstructive sleep apnea syndrome (OSAS) were investigated.

Retrospective study with case groups.

Ten aged adults with severe OSAS (average age 75, average apnea-hypopnea index 43.8) were examined via time-matched digital recordings of polysomnography and surface electromyography of the muscles (thyrohyoid and suprahyoid) related to swallowing and compared with aged adults without OSAS previously reported on.

During sleep, swallowing was infrequent and absent for long periods. The median number of swallows per hour during total sleep time was 4.1 and the median longest deglutition-free period was 70.5 minutes. Three-fourths of deglutition occurred in association with respiratory electroencephalographic arousal. Deglutition was related to the sleep stage. The deeper the sleep stage, the lower the mean deglutition frequency. The median number of swallows per hour was 5.7 during stage N1 sleep and 2.8 during stage N2 sleep. There was no deglutition during stage N3 (deep) sleep. The median number of swallows per hour was 0.6 during REM sleep. Approximately 40% of swallows occurred after inspiration and approximately 42% were followed by inspiration.

Deglutition was infrequent and respiratory phase patterns were unique during sleep in the aged with OSAS. Sleep-related deglutition and respiratory phase patterns may adversely influence aspiration-related diseases (aspiration pneumonia, etc) in the aged with sleep-related breathing disorders.

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