Chronious: A new wearable monitoring system for COPD patients

CHRONIOUS is a FP7 European Community project which also includes a new wearable platform for home monitoring of people suffering from chronic diseases. The wearable system is composed of a shirt made of washable stretch-material into which are sewn 4 ECG electrodes, two bands for respiratory inductive plethismography (RIP) and a reflectance pulseoximeter. The data coming from the sensors are collected and transmitted via wireless connection by the Data Handler, a microcontroller-based acquisition system. To evaluate accuracy and usability of this device, we studied 9 COPD patients (70.8±6.6 years, FEV1 45.1±9%pred) during 1 hour in the seated and 1hour in the supine positions. Patients were breathing spontaneously and data were collected continuously. At the beginning and at the end of each hour flow at the mouth was also measured by a spirometer (Sibelmed, Barcelona, Spain), heart rate (HR) and oxygen saturation (SpO2) by a finger clip pulseoximeter (NONIN, Plymouth, Minnesota, USA) for 10 minutes, to get reference values for comparison. The first measurement for each subject with the spirometer was used to calibrate the RIP using Sackner algorithm, J.Appl.Physiol 1989; 66(1): 410-420. The evaluation of accuracy was focused on the following parameters: HR, SpO2 and tidal volume (VT). Linear regression analysis on the data acquired resulted as follows: HR r 2 =0.99, m=1.00, q=-0.31, SpO2 r 2 =0.92, m=1.29, q=-27.54, VT r 2 =0.89, m=1.15, q=-0.072. From the signals of the ECG electrodes it was possible to identify PQRST waves within the 3 derivations. The new wearable monitoring system provided reliable measurements of HR, SpO2, VT and ECG in both supine and seated posture. RIP calibration was still consistent after 1 hour of use.