12-14-2009, 07:56 PM
5.  Three days after undergoing colectomy for colon cancer, a 77-year-old woman has the sudden onset of severe shortness of breath. She says she cannot catch her breath. Current medications include subcutaneous heparin and patient-controlled morphine. Her temperature is 37°C (98.6°F), pulse is 140/min, respirations are 28/min, and blood pressure is 110/60 mm Hg. Pulse oximetry on room air shows an oxygen saturation of 89%. Breath sounds are decreased on the right. Abdominal examination shows an intact surgical incision with no erythema or discharge. Arterial blood gas analysis shows:
Â
pH
7.38
Pco2
23 mm Hg
Po2
55 mm Hg
Â
A chest x-ray shows atelectasis at both lung bases. An ECG shows nonspecific ST-T wave changes. In addition to oxygen therapy, which of the following is the most appropriate next step in management?
A Spiral CT scan of the chest
B Oral warfarin therapy
C Intravenous administration of a recombinant tissue plasminogen activator
D Pulmonary angiography
E Placement of a vena cava filter