Abstract Rationale Early diagnosis of COPD exacerbation allows for earlier treatment, reducing the frequency and severity of exacerbation. Clinically, the diagnosis of COPD exacerbation is based on symptoms. However, efforts to develop a scoring system to predict COPD exacerbation have not been successful. Many patients are not able to recognize the initial symptoms, resulting in a delay in diagnosis and treatment. Frequent spirometry may help predict COPD exacerbation, but the availability and utilization of spirometry is low. The diaphragm is flattened by lung hyperinflation with reduced mobility in COPD patients. The diaphragmatic thickening fraction (DTF) abnormalities are present before COPD exacerbation. We are developing a wearable ultrasonic device to continuously monitor DTF to predict COPD exacerbation. Methods We developed a wearable ultrasonic device that can be attached to the skin at the intercostal area close to the diaphragm. The device has a fully integrated circuit board to record ultrasound waves and transfer the data to generate M-mode images of the diaphragm. We recruited healthy subjects and COPD patients for testing. First, we tested if the device could generate M-mode images comparable with a commercial ultrasound machine. Second, we tested if the device could differentiate diaphragm movement patterns in healthy subjects and COPD patients. Third, we studied if the device could provide continuous monitoring of the diaphragm movement and DTF. Results The wearable ultrasonic device recorded thousands of frames of ultrasound signals and then processed them to form M-mode images, which were comparable with those from commercial ultrasound machine. We can identify the hyper-echogenic pleural and peritoneal membranes. The distance between these two layers is the diaphragm thickness. The diaphragm excursion and thickening in COPD patients are reduced compared to healthy subjects, and a significantly longer expiratory phase with a lower inspiratory-to-expiratory (I:E) ratio is observed. Our wearable ultrasonic device can capture the diaphragm movement continuously and reliably to provide continuous DTF measurements. Conclusions Our device can provide the longitudinal data for DTF. Like spirometry, the DTF can serve as the baseline to predict COPD exacerbation. The study for the correlation between DTF, spirometry and COPD exacerbation is ongoing. Our device has several advantages: it is wearable, wireless, provides continuous monitoring, and can be used at home with the data being transferred to a physician’s office. The monitoring of DTF data can help predict COPD exacerbation and promote early diagnosis and treatment. This abstract is funded by: NIH
Li et al. (Fri,) studied this question.