A 56-year-old man is been admitted to the medical intensive care unit (MICU) in respiratory distress. An endotracheal tube is placed for mechanical ventilation at a tidal volume of 900 mL, a rate of 12 breaths/min, and a fraction of inspired oxygen of 50%. The positive end expiratory pressure is 10 cm of water. Medications include subcutaneous heparin and aspirin. Forty-eight hours into his MICU stay he develops tachycardia and a blood pressure of 70/palpation mm Hg. Cardiac examination at this time reveals multiple premature contractions. His arterial blood gas reveals a PO2 of 40 mm Hg. Which of the following is the most likely cause of this condition?
A. Cardiac arrhythmia
B. Bronchial secretions
C. Myocardial infarction
D. Pneumothorax
E. Pulmonary embolus
A. Cardiac arrhythmia
B. Bronchial secretions
C. Myocardial infarction
D. Pneumothorax
E. Pulmonary embolus