In this paper we present a device for improving blood oxygenation in patients with Acute Respiratory Distress Syndrome (ARDS). ARDS is caused by lung-related illness or injury, and can occur in mechanically ventilated ICU patients due to volutrauma or barotrauma. In ARDS, the lower lung is closed resulting in impaired gas exchange, and the upper lung is easily overstretched resulting in injury. The application of continuous negative abdominal pressure (CNAP) assists in opening the lower lung by pulling the diaphragm towards the abdomen. The device, consisting of a rigid arch, a compliant patient interface, and a pressure sensor module, allows for the application of CNAP to a patient suffering from ARDS.
An initial pig trial using the prototype device showed significant improvement in the ratio of oxygen in the blood to the fraction of inspired oxygen, PaO2/FiO2, after five minutes of −5 cmH2O pressure application. Furthermore, preliminary testing on healthy humans indicated the device was comfortable, easy to apply, and formed a consistent airtight seal. Future prototypes will focus on ease of application, rigidity, and adjustability.