Preliminary Detection of Acute Exacerbation of Lobar Pneumonia and Heart Failure Using an Anomaly-Detection System Based on a Circadian Rhythm Model Constructed from Non-contact Vital Data

Many frail older patients with multiple comorbidities are hospitalized in long-term care hospitals and nursing facilities. Due to pre-existing conditions and immunosuppressive states, there are significant individual differences, such as weakness, sluggishness, and asymptomatic status. These differences make it challenging to find a patient's exacerbation using a conventional threshold of vital signs. We developed a circadian rhythm anomaly-detection system designed for each patient, which compares each patient's past 2 weeks average respiratory rate circadian rhythm with that of the last 24 hours. Respiratory rate was measured using a piezoelectric sensor located under the mattress. Prior to the doctor's diagnosis of acute exacerbation of lobar pneumonia and heart failure, a bedridden 88-year-old female patient with multiple chronic diseases showed abnormal circadian rhythm status. However, there were no significant changes in vital signs. A circadian rhythm anomaly-detection system appears promising as a future tool to promote medical checkups for the older person.