On physical examination, she was dyspneic, cyanotic, and clammy. Her temperature was 98.4°F, pulse was 126 beats/min and regular, respiration was 40 breaths/min, and systolic BP was 70 mm Hg. The oxygen saturation was 85% while breathing room air. The physical examination findings were notable for bilateral rhonchi and a diffuse, blanching, erythematous macular rash. Laboratory values included a WBC count of 9,700 cells/μL with a normal differential, hematocrit of 52.7%, and a platelet count of 219,000 cells/μL. The results of coagulation studies were normal. The BUN concentration was 53 mg/dL, creatinine concentration was 5.5 mg/dL, lactic acid concentration was 7.5 mmol/L, creatine kinase concentration was 437 U/L (with an MB fraction of 15.9 ng/mL), and troponin I concentration was 0.7 ng/mL. The arterial blood gas levels measured through a nonrebreather oxygen mask were pH 7.15, Pco2 of 39.8 mm Hg, Po2 of 209 mm Hg, arterial oxygen saturation of 99.4%, and calculated HCO3 concentration of 13.4 mmol/L. An ECG showed sinus tachycardia without evidence of ischemia. A chest radiograph (Fig 1
) showed focal consolidation in the right upper lobe.