Incidence of early pulmonary embolism after injury

Pulmonary embolism (PE) is a well-recognized potentially fatal complication after trauma. PE is generally thought to occur days after the acute injury. Hypoxia early after injury is often ascribed to other causes. We hypothesized that PE often occurs early after injury and we sought to elucidate the timing of PE after trauma.

The trauma registry was used to identify all patients diagnosed with an acute PE between June 1999 and December 2004. Medical records were reviewed and demographics, injury specific data, length of stay, comorbidities, and mortality were recorded. Time from injury to diagnosis was recorded as was diagnostic modality and treatment.

In total, 35,424 patients were treated in our trauma center during the study period. Ninety-four patients with PE were identified (0.27%). Mean age was 45 (+/-18.5) years and mean Injury Severity Score was 23 (+/-11.4). Of the total patients, 82% were male and 91.6% sustained blunt trauma. Mean length of stay was 25 (+/-32.1) days. Anatomic areas injured included thorax (37%), lower leg/femur (38%), pelvis/acetabulum (22%), and spine (30%). The diagnosis was confirmed radiographically in 91 patients; two pulmonary emboli were confirmed at autopsy and one, despite a negative CT scan, was treated based on clinical suspicion. Of these 94 patients diagnosed with a PE, the PE was detected by angiogram in 5 (5%), ventilation/perfusion scan in 10 (11%), and computed tomography scan in 76 (81%). PE was diagnosed on day 1 to 4 in 35 patients (37%), on day 5 to 7 in 17 patients (18%), on day 8 to 14 in 22 patients (23%), and after 14 days in 20 patients (21%). Eleven percent died, but only two deaths were attributed to PE.

PE remains relatively common after trauma and occurs in the absence of lower extremity or spinal fractures. Although PE is usually thought to occur between days 5 and 7 after injury, our data suggest that as many as 37% of pulmonary emboli occur early. Clinicians should consider PE in the differential for patients with unexplained hypoxia, even early after injury.