“…Owing to this fast response speed, the QCM-5 sensor can monitor human respiration in real-time. It is widely known that the respiratory rate of an adult is usually 12–20 times/min. − Rapid breathing (tachypnea) refers to the respiratory rate more than 20 times/min, which is often found in septicemia, acidosis, pneumonia, pleural effusion, asthma, and allergic reaction. , Slow breathing (bradypnea) refers to the respiratory rate lower than 12 times/min, which is common in anesthetics, impending respiratory failure, central nervous system disorders, and so on . Therefore, real-time monitoring of respiration is of great significance for respiratory disease diagnosis.…”