This Figure provides some background on the AVAPS-AE system that these patients used.  AVAPS-AE is an autotitration mode for delivery of noninvasive positive pressure ventilation (NIPPV) that is designed to treat patients with respiratory insufficiency in both in-hospital and home-care environments.  Specifically, this mode of NIV maintains target tidal volume, patient upper airway at a comfortable pressure, and applies an auto backup rate that is near the patient’s breathing frequency.