Shock Lung

This chest x-ray is from a 40 year old man with no past medical history who initially presented with sepsis from pyelonephritis (or trauma or a viral pneumonia or pancreatitis or aspiration). He was treated appropriately early on but developed tachypnea, tachycardia, accessory muscle use, and hypoxemia. Note that he has an endotracheal tube. His ventilator settings are assist control with an FiO2 of 80%, a PEEP of 10, and a respiratory rate of 28. His blood gas is pH 7.24, PaCO2 48, PaO2 66. His echocardiogram shows low-normal systolic function, no severe valvular abnormalities, no significant effusion.

Challenge: How do you set the tidal volume on the ventilator?

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