Respiratory resistance measurements with the airflow perturbation device

The airflow perturbation device (APD) is a new device for measuring respiratory resistance. What makes it different is the convenience and ease of use. The device operates by small changes in respiratory airflow and mouth pressure induced by a rotating wheel in the air flow path. Resistance measurements do not require special breathing maneuvers and can be made on small children and unconscious or uncooperative humans and animals. Measurements are sensitive to changes and are reproducible.