Objective
Computed tomography (CT) is used in the diagnostic management of polytraumatized patients. Multiple trauma and pulmonary contusion are typical triggers of post-traumatic acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) [1]. Therefore, an early predictor of post-traumatic ALI/ARDS would be valuable. In this study we tested whether the mass of nonaerated lung tissue (Mnon) in admission CT could predict post-traumatic ALI/ARDS.
Methods
The Mnon of 54 polytraumatized patients with pulmonary contusion was analyzed as previously described [2]. We studied the association of Mnon with physiologic variables and injury descriptors such as PaO2/FiO2 ratio, injury severity score (ISS) and thoracic trauma severity score (TTSS) [3] recorded on admission. To evaluate Mnon as a predictor of ALI/ARDS we used a receiver operator characteristic (ROC) curve.
Results
Patients developing post-traumatic ALI/ARDS had significantly larger Mnon and significantly higher ISS and TTSS values. Literature data suggest a higher incidence of ALI/ARDS with a contusioned lung volume >20% [4]. Our results, however, indicate a higher risk of ALI/ARDS already with a Mnon of around 10%. The Mnon predicting ALI/ARDS with the highest sensitivity (81%) and specificity (87%) was 9.8%. The area under the ROC curve was 0.89 (confidence interval 0.79–0.99).
Conclusion
The mass of nonaerated lung tissue on admission CT can help to predict the development of ALI/ARDS. It may thereby help to implement appropriate therapeutic options such as lung protective ventilation. The clinical use of our technique, however, is limited by the time-consuming CT analysis.