Arterial blood gas analysis utility in predicting lung injury in blunt chest trauma

Abstract

Background: thoracic trauma is one of the leading causes of death in all age groups and accounts for 25-50 % of all traumatic injuries. With the term lung injury in blunt chest trauma, we identified a spectrum of conditions: lung contusion, pneumothorax and haemothorax. The aim of this study was to evaluate the utility of arterial blood gas analysis parameters in predicting lung injury in blunt chest trauma.

Methods: we included 51 patients presenting to the Emergency Department of "C.T.O." Hospital in Naples [Italy] for blunt chest trauma. The patients were assigned to the Lung Injury Group or to the Non-Lung Injury Group basing on CT scan findings. For each patient, we calculated the alveolar-arterial oxygen gradient [AaDO₂], the AaDO₂ augmentation, the arterial partial pressure of oxygen deficit [PaO₂ Deficit] and the ratio between arterial partial pressure of oxygen and fraction of inspired oxygen [P/F]. Areas under the curve [AUC] and receiver operating characteristic [ROC] curve were used to compare the performance of each different test in relation to the detection of lung injury in blunt chest trauma.

Results: patients with lung injury had lower oxygen saturation, arterial partial pressure of oxygen, P/F and higher PaO₂ Deficit, AaDO₂, AaDO₂ augmentation than patients without lung injury. PaO₂ Deficit, AaDO₂ and AaDO₂ augmentation showed a good accuracy to predict lung injury in blunt chest trauma.

Conclusion: our study demonstrates that the combination of different arterial blood gas analysis variables may be a fast approach for identifying patients with lung injury in the setting of blunt chest trauma in the Emergency Department.

Keywords: Alveolar-arterial oxygen gradient; Haemothorax; Hypoxemia; Lung contusion; Partial pressure of oxygen; Pneumothorax.