Massive pulmonary embolus without hypoxemia.

OBJECTIVE: To describe a patient who had been taking ibuprofen for 3 days before the diagnosis of a massive pulmonary embolus without hypoxemia.

DESIGN: Institutional review board-approved case report.

SETTING: Pediatric intensive care unit.

PATIENT: A 16-yr-old male with a history of supraventricular tachycardia.

RESULTS: The patient underwent an electrophysiology study and developed mild shortness of breath and then chest pain 2 and 4 days later, respectively. He took ibuprofen for 3 days. Evaluation 1 wk following the procedure revealed dyspnea and tachycardia. Arterial blood gas in room air was significant for hypocarbia without hypoxemia (Pao2, 108 mm Hg; Paco2, 28 mm Hg). Ventilation perfusion scan and computed axial tomography with intravenous contrast were consistent with a massive pulmonary embolus and left external iliac vein thrombus. He received anticoagulation, thrombolysis, a stent in the left iliac vein, and a filter in the inferior vena cava. Perfusion gradually improved and he was discharged home on oral anticoagulation.

CONCLUSIONS: The absence of hypoxemia (including a normal alveolar-arterial oxygen difference) in our patient with a massive pulmonary embolus may have been related to cyclooxygenase inhibition due to ibuprofen, with improvement in ventilation-perfusion mismatch.