08-14-2014, 11:47 AM
A 61-year-old man with atrial fibrillation for which he is taking amiodarone presents to the emergency department in respiratory failure. He requires endotracheal intubation, central venous line placement, and the initiation of vasopressors, and is sent to the intensive care unit. His wife reports that he had been complaining of shortness of breath since he awoke 8 hours ago. Laboratory tests show:
WBC count: 9300/mm³
Hemoglobin: 6.4 g/dL
Hematocrit: 19.1% (baseline 39.8%)
Platelet count: 193,000/mm³
Arterial blood gas analysis reveals a pH of 7.33, partial carbon dioxide pressure of 46 mm Hg, and partial oxygen pressure of 94 mm Hg. Ventilator settings include:
Assist-control ventilation
Tidal volume: 400 mL
Respiratory rate: 12/min
Fraction of inspired oxygen: 80%
Recent echocardiography reveals a left ventricular ejection fraction >55%, and a bedside echocardiogram shows the patient to be in sinus rhythm with no significant abnormalities in cardiac function, including the lack of left ventricular hypertrophy and normal diastolic relaxation. X-ray of the chest shows bilateral infiltrates.
Which of the following is the most likely diagnosis?
A.Acute lung injury
B.Acute respiratory distress syndrome resulting from multifocal pneumonia
C.Diffuse alveolar hemorrhage
D.Massive pulmonary embolus
E.Systolic congestive heart failure