system
Medical AI Inquiry: You were designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.
user
A 70-year-old man comes to the emergency room for worsening leg pain and a rash consistent with wet gangrene. He has no history of skin infections but has type 2 diabetes mellitus and has smoked 2 packs of cigarettes daily for 20 years. Three days after admission, he becomes increasingly hypoxic and tachypneic. He is emergently intubated and ventilatory support is initiated. He is 180 cm (5 ft 11 in) tall and weighs 90 kg (198 lb); BMI is 27.8 kg/m2. His pulse is 112/min and his blood pressure is 95/60 mmHg. The ventilator is set at an FIO2 of 100%, tidal volume of 540 mL, respiratory rate of 20/min, and positive end-expiratory pressure (PEEP) of 5 cm H2O. On pulmonary examination, there are diffuse crackles. Cardiac examination shows no abnormalities. Hemoglobin is 11.5 g/dL, serum lactate is 4.0 mmol/L, and serum creatinine is 2.5 mg/dL. An arterial blood gas checked 30 minutes after intubation shows a PaCO2 of 50 mm Hg and a PaO2 of 55 mm Hg. An x-ray of the chest shows new bilateral infiltrates. Which of the following is the most appropriate next step to improve tissue oxygen delivery in this patient?
assistant
Increase the positive end-expiratory pressure