A client with acute respiratory distress syndrome (ARDS) is mechanically ventilated and on a cardiac monitor. On shift change, the receiving nurse is told the health care provider (HCP) was just in the room and made changes to the ventilator settings. Fifteen minutes later, the cardiac monitor alarms showing: HR 55, SpO₂ 88%, and arterial BP 80/56mmHg. Which setting on the ventilator is critical for the nurse to check at this time?