A 45-year-old previously healthy woman presents to the emergency department with 3 days of fevers and progressive dyspnea and is admitted to the intensive care unit (ICU) for influenza infection complicated by severe hypoxemia. She is intubated, and chest radiograph following intubation demonstrates an appropriately placed endotracheal tube with bilateral patchy opacities and interstitial markings throughout all lung fields, without effusions. Her bedside echocardiogram reveals a left ventricular ejection fraction of 0.75 with otherwise normal findings. Her ventilator settings are:
An initial arterial blood gas (ABG) is:
Which of the following therapies has been best shown to improve the survival of patients such as this woman?A. Diuresis to maintain a negative fluid balance
Correct Answer: B
This patient is presenting with severe ARDS, as defined by the Berlin criteria: onset within 1 week or presentation, bilateral opacities on imaging, edema not fully explained by cardiogenic etiology, and PaO2 :FiO2 ratio of <100. The ARDSnet trial demonstrated a significant mortality benefit with lung protective, low-TV ventilation (6 mL/kg IBW) (answer B is correct). Diuresis to an even fluid balance increases ventilator-free days in patients with ARDS but has not been found to have a mortality benefit (answer A is incorrect). Similarly, while inhaled nitric oxide and PEEP titration may improve oxygenation, neither intervention has been demonstrated to improve survival (answers C and E are incorrect). Invasive respiratory cultures are not recommended in patients with severe community acquired pneumonia (answer D is incorrect).