Respiration is one of the important signals to judge the condition of a patient psychophysiologically. Respiratory monitoring of patients, especially under sedation, is one of the important signals. However, patient’s apnea and low respiratory conditions are usually difficult to detect without continuous monitoring, so accurate, simple, and continuous breathing monitoring methods are needed that can determine the patient''s respiratory status noninvasively. In particular, respiration rate is a very important factor in clinical practice. Currently, respiration monitoring methods using various devices have been developed. However, these methods show a slow response time and inaccurate respiratory tracking limit in clinical use.
In this study, a wearable sensor using PVDF (polyvinylidene fluoride) film was designed and fabricated, and a monitoring device was developed for early detection of respiratory abnormalities by detecting breath sounds during dental anesthesia and endoscopy using sedation. In other words, it is aimed to monitor respiratory sounds while minimizing the risk factors that may occur even during the calming procedure.
The PVDF sensor was designed to detect the respiratory function through the sound recorded in the vibration of the surface of the neck, and the analog circuit for processing the film output was designed. Then, the respiration sound was detected in subjects, and the accuracy and reliability of the breath sounds were evaluated by applying signal processing algorithms such as rectification, smoothing, threshold setting, and breath count calculation. As a result, the correlation coefficient between the actual breathing rate and the respiration rate from the detected signal using the developed sensing system was 0.976, which is statistically significant.
The results of this study can be used as a monitoring system to prevent the risk that may occur in the procedure in advance by diagnosing an abnormal symptom of a patient in various medical departments using a sedation.