A middle-aged man with obstructive sleep apnea who had been treated with continuous positive airway pressure developed COVID-19. An analysis of airflow records from the continuous positive airway pressure machine revealed a rise in his respiratory rate on the night before the onset of COVID-19-related symptoms, while his nocturnal respiratory rate had been stable during the 18-month period prior to the presently reported episode. The present case suggests that a rise in respiratory rate detected using continuous positive airway pressure machine data could be an important sign of impending acute illness, such as COVID-19. Studies to elucidate the usefulness of this method are warranted.

Nakano H, Kadowaki M, Furukawa T, Yoshida M. Rise in nocturnal respiratory rate during CPAP may be an early sign of COVID-19 in patients with obstructive sleep apnea. J Clin Sleep Med. 2020;16(10):1811–1813.