Assuring consistency of respiratory resistance measurements

We have developed a simple pulmonary diagnostic device that measures respiratory resistance of adults and children. The device is Airflow Perturbation Device (APD). There are many commercially available respiratory diagnostic devices in clinical use, but the major advantage of the APD is that it is an effortless device that evaluates the respiratory resistance effortlessly. Further, it can do this only by normal breathing through the device for less than one minute. To assure the consistency of the respiratory resistance values obtained using the APD, we designed a system that simulates the normal range of human breathing. We further compared the APD readings with a clinically accepted respiratory diagnostic system, the Impulse Oscillometry (IOS). IOS is an FDA approved system that also, similar to APD, measures respiratory resistance. The measurements using the APD and IOS were conducted at constant volumetric flow rate of 0.15 L·s^-1. The results show that the resistance values obtained from the APD and IOS were consistent and linearly correlated (R²=0.999), we were then assured that the respiratory resistance values obtained using the APD are valid and consistent.