Experiences Using Airway Pressure Release Ventilation for Pneumonia with Severe Hypercapnia or Postoperative Pulmonary Edema

Airway pressure release ventilation (APRV) was introduced as a new method to manage a supportive level of continuous positive airway pressure (CPAP) while simultaneously assisting CO2 elimination [1,2]. APRV maintains CPAP while permitting spontaneous breathing without airway pressure fluctuation [2] and producing alveolar ventilation [3]. It is an established mode of ventilation based on the openlung approach with the following settings: (1) pressure during the in- spiration/ CPAP phase (Phigh); (2) time during the inspiration/CPAP phase (Thigh); (3) pressure during the expiration/release phase (Plow); (4) time during the expiration/ release phase (Tlow); and (5) percent CPAP (%CPAP) to reflect the time spent at Phigh relative to the entire breath duration [2] during which positive pressure (Phigh) was applied for a prolonged time (Thigh) with a release phase (Plow) that is short (Tlow) [1,4,5]. Without self-breathing, the APRV mode is like pressure-controlled inverse ratio ventilation [3].