S. Gambhir1, A. Grigorian1, A. Ashbaugh1, D. Spencer1, D. Ramakrishnan1, J. Nahmias1 1University Of California – Irvine,Surgery,Orange, CA, USA
Introduction: Pulmonary embolism (PE) is an uncommon complication occurring in up to 5% of trauma patients. In small previous studies, it has been demonstrated that patients with long bone fractures are associated with a higher risk of early PE while those with severe head injuries are at higher risk for late PE. We sought to confirm risk factors for early and late PE previously reported in the literature, hypothesizing that early PE would be associated with long bone fractures and late PE would be associated with above-the-knee DVT.
Methods: This was a retrospective analysis using the trauma registry at a Level-I center from 2010-2017. Patients with early PE (≤ 4 days) were compared to those with late PE (> 4 days) with bivariate and multivariable analysis.
Results: A total of 77 patients (0.6% incidence of PE) were included with 43 (53.1%) diagnosed with late PE. Compared to those with early PE, those with late PE had similar age (p=0.97) and rate of obesity (p=0.20) but a higher rate of severe (grade>3) abbreviated injury scale (AIS) for the head (39.5% vs. 15.2%, p=0.02). Those with late PE had a higher rate of blood product transfusion (39.5% vs. 6.1%, p<0.001), craniotomy (23.3% vs. 3.0%, p=0.01), venous thromboembolism chemoprophylaxis (86.0% vs. 42.4%, p<0.001) and above-the-knee DVT (29.7% vs. 3.1%, p=0.004), compared to those with early PE. The incidence of long bone extremity fractures was similar (p>0.05). After adjusting for age≥ 65, injury severity score ≥ 25 and gender, independent risk factors for late PE included above-the-knee DVT (OR=12.01, CI=1.34-107.52, p=0.03), blood transfusion (OR=8.99, CI=1.75-46.22, p=0.009) and craniotomy (OR=8.82, CI=1.03-75.97, p=0.04) while the only independent risk factor for early PE was smoking (OR=4.56, CI 1.06-19.66, p=0.04).
Conclusion: The strongest risk factor for late PE is above-the-knee DVT. Contrary to previous reports, long bone extremity fractures are not at higher risk for early PE and severe head injuries are not at higher risk for late PE but this may be related to our study being underpowered. The only independent variable associated with higher risk of early PE is a history of smoking. A future prospective multicenter study will help confirm our findings and determine if early screening of smokers may be beneficial