Q. A 38-year-old male was found unresponsive at a homeless shelter and transported to the emergency department. Staff at the shelter report the patient stays there regularly, and is known to consume significant quantities of alcohol daily. No other information is available regarding his past medical history. On physical examination, the patient is disheveled, somnolent, and diaphoretic. No visible signs of trauma are noted, though there does appear to be a moderate amount of non-bloody gastric contents on his shirt and jacket. His blood pressure is 135/90 mm Hg, pulse 110/min, respiratory rate 40/min, and oxygen saturation is 85 percent on room air. Cardiopulmonary assessment demonstrates his heart is in regular rhythm with no murmurs, rubs, or gallops. Diffuse crackles are noted in both lung fields. Remaining physical examination is unremarkable, with no signs of peripheral edema. Oxygen is provided via facemask and has little effect on his saturation levels. Based on an arterial blood gas demonstrating acute respiratory alkalosis with an elevated alveolar-arterial oxygen gradient, you choose to intubate the patient, and his post-procedure chest x-ray (see image) shows diffuse infiltrates with no effusions or consolidations. Based on what you know at this point, which of the following is the best choice for the initial ventilator settings?