Deglutition and respiratory patterns during sleep in the aged with OSAS

Incidence and risk factors of nocturnal penetrations and aspirations in patients with obstructive sleep apnea during drug-induced sedation endoscopy

Obstructive sleep apnea has been linked to an increased risk of pneumonia, possibly due to higher rates of nighttime aspirations. Few studies have directly investigated such aspirations in individuals with sleep apnea. This retrospective study included 142 adult patients with obstructive sleep apnea who underwent drug-induced sedation endoscopy between 2017 and 2020. The incidence of penetrations and aspirations during the procedure was assessed, along with potential associated factors. The results showed that 28.1% of the patients experienced penetrations, 48.5% had aspirations, and 23.2% had neither. Male gender and epiglottic collapse were significantly associated with both penetrations and aspirations, while oropharyngeal collapse was more common in those without these events. This study highlights a high rate of aspirations during the procedure in individuals with sleep apnea, with epiglottic collapse and male gender identified as potential risk factors. These findings underscore the need for further research to understand the mechanisms of nighttime aspirations in sleep apnea and to develop targeted strategies to reduce pneumonia risk in this population.

Comparison of electromyography, sound, bioimpedance, and high-resolution manometry for differentiating swallowing and vocalization events

OBJECTIVES

Non-invasive surface recording devices used for detecting swallowing events include electromyography (EMG), sound, and bioimpedance. However, to our knowledge there are no comparative studies in which these waveforms were recorded simultaneously. We assessed the accuracy and efficiency of high-resolution manometry (HRM) topography, EMG, sound, and bioimpedance waveforms, for identifying swallowing events.

METHODS

Six participants randomly performed saliva swallow or vocalization of "ah" 62 times. Pharyngeal pressure data were obtained using an HRM catheter. EMG, sound, and bioimpedance data were recorded using surface devices on the neck. Six examiners independently judged whether the four measurement tools indicated a saliva swallow or vocalization. Statistical analyses included the Cochrane's Q test with Bonferroni correction and the Fleiss' kappa coefficient.

RESULTS

Classification accuracy was significantly different between the four measurement methods (P < 0.001). The highest classification accuracy was for HRM topography (>99%), followed by sound and bioimpedance waveforms (98%), then EMG waveform (97%). The Fleiss' kappa value was highest for HRM topography, followed by bioimpedance, sound, and then EMG waveforms. Classification accuracy of the EMG waveform showed the greatest difference between certified otorhinolaryngologists (experienced examiners) and non-physicians (naive examiners).

CONCLUSION

HRM, EMG, sound, and bioimpedance have fairly reliable discrimination capabilities for swallowing and non-swallowing events. User experience with EMG may increase identification and interrater reliability. Non-invasive sound, bioimpedance, and EMG are potential methods for counting swallowing events in screening for dysphagia, although further study is needed.

From SARS-CoV-2 infection to COVID-19 morbidity: an in silico projection of virion flow rates to the lower airway via nasopharyngeal fluid boluses

Background: While the nasopharynx is initially the dominant upper airway infection site for SARS-CoV-2, the physiologic mechanism launching the infection at the lower airway is still not well-understood. Based on the rapidity of infection progression to the lungs, it has been hypothesized that the nasopharynx may be acting as the primary seeding zone for subsequent contamination of the lower airway via aspiration of virus-laden boluses of nasopharyngeal fluids. Methodology: To examine the plausibility of the aspiration-driven mechanism, we have computationally tracked the inhalation process in three anatomic airway reconstructions and have quantified the nasopharyngeal liquid volume transmitted to the lower airspace during each aspiration. Results: Extending the numerical trends on aspiration volume to earlier records on aspiration frequencies indicates a total aspirated nasopharyngeal liquid volume of 0.3 – 0.76 ml/day. Subsequently, for mean sputum viral load, our modeling projects that the number of virions reaching the lower airway will range over 2.1×106 – 5.3×106 /day; for peak viral load, the corresponding number hovers between 7.1×108 – 1.8×109. Conclusions: The virion transmission findings fill in a key piece of the mechanistic puzzle on the systemic progression of SARS-CoV-2, and subjectively point to health conditions like dysphagia, with proclivity to increased aspiration, as some of the potential underlying risk factors for aggressive lung infections.

Recurrent aspiration pneumonia precipitated by obstructive sleep apnea

OBJECTIVE

The clearance of the pharynx by deglutition and the respiratory phase patterns associated with deglutition are important in protecting airways and lungs against aspiration. The deglutition and respiratory phase patterns during sleep in patients (without swallowing disorders while awake) with obstructive sleep apnea (OSA) precipitating recurrent intractable aspiration pneumonia were investigated.

METHODS

After videoendoscopic and videofluorographic examinations of swallowing showed subjects had no swallowing disorders while awake, two adults with recurrent intractable aspiration pneumonia precipitated by severe OSA were examined via time-matched digital recordings of polysomnography and surface electromyography of the muscles (thyrohyoid and suprahyoid muscles) related to swallowing and compared with the same patients before and under CPAP therapy.

RESULTS

CPAP therapy cured recurrent intractable aspiration pneumonia. Swallows following and/or followed by inspiration (uncoordinated deglutition with respiration), which were frequently observed before CPAP therapy, were markedly reduced under CPAP therapy. On the other hand, swallows following and/or followed by expiration (coordinated deglutition with respiration) markedly increased under CPAP therapy. Deglutition was related to the sleep stage. The deeper the sleep stage, the lower the deglutition frequency. Before and under CPAP therapy, swallowing was infrequent and absent for long periods. However, respiratory phase patterns associated with sleep-related deglutition in patients with OSA under CPAP therapy markedly improved.

CONCLUSIONS

In patients (without swallowing disorders while awake) with OSA precipitating recurrent intractable aspiration pneumonia, the high rate of uncoordinated deglutition with respiration (swallows following and/or followed by inspiration) during sleep were markedly reduced and the rate of coordinated deglutition with respiration (swallows following and/or followed by expiration) was markedly increased under CPAP therapy. Sleep-related deglutition and respiratory phase patterns are likely to adversely influence aspiration pneumonia in patients with OSA. CPAP therapy improved not only apnea-hypopnea during sleep and sleep quality but also sleep-related deglutition, especially respiratory phase patterns associated with deglutition in patients with OSA. CPAP therapy may decrease the risk of aspiration and greatly improve aspiration-related diseases such as aspiration pneumonia.

Sleep-related deglutition and respiratory phase patterns in the aged with obstructive sleep apnea under CPAP therapy

Background: Respiratory phase patterns associated with deglutition and clearance of pharynx by deglutition are important in protecting airways and lungs against aspiration.Aims/objectives: Sleep-related deglutition and respiratory phase patterns in the aged with obstructive sleep apnea (OSA) before and under CPAP therapy were investigated.Materials and methods: Ten aged adults with severe OSA under CPAP therapy were examined by polysomnography and surface electromyography of the muscles related to swallowing and compared with the same patients before CPAP therapy.Results: Under CPAP therapy, swallowing was also infrequent and absent for long periods. The deeper the sleep stage, the lower the deglutition frequency. The median number of swallows per hour during total sleep time was 1.5 and the median longest deglutition-free period was 74.5 min. Swallows following and/or followed by inspiration, which were observed a great deal before CPAP therapy, were markedly reduced. On the other hand, swallows following and/or followed by expiration markedly increased. Approximately, 73.5% of swallows occurred after expiration and approximately 66.8% were followed by expiration. Respiratory phase patterns associated with sleep-related deglutition improved under CPAP.Conclusions/significance: CPAP therapy improved sleep-related deglutition and respiratory phase patterns in the aged with OSA.