Correlating the extent and location of pulmonary contusion to vehicle crash parameters

Pulmonary contusion is a common injury following motor vehicle crash (MVC). The estimated mortality rates for this injury range from 10% to 20%. Another important clinical implication of this lesion is the potential for development of Acute Respiratory Distress Syndrome (ARDS). Studies have correlated an increased risk of ARDS with a pulmonary contusion extent exceeding 20% of the total lung volume. The mechanism of injury for pulmonary contusion is a mechanical insult that leads to an inflammatory response. To better predict possible injury to an occupant following a MVC, this study correlates the resulting percent injury to the lung (inflammatory response) to crash parameters (mechanical insult). The Wake Forest University CIREN database was queried to extract all occupants sustaining pulmonary contusion in a near-side crash. CIREN was selected because of the extensive medical history of the occupant, imaging studies of the injury, and in-depth crash investigations. Specific crash characteristics selected were the vehicle type, object struck, change in velocity due to the impact, principal direction of force of the crash, and vehicle components contacted by the occupant. Additionally, the extent of the crush was calculated as the area of the crush. The radiological studies were segmented to determine the percent volume of high radiopacity lung as compared to the total volume of the lung. The mean impact severity for the cases with pulmonary contusion below 20% was 36.14 kph, with a range of 13 to 68 kph. In comparison, the mean severity for cases above this value was 40.9 kph, with a range of 25 to 56 kph. Using the same grouping of above or below 20% volume, maximum crush was a significant predictor of the pulmonary contusion higher volume group with a p-value of 0.0427. Additionally, the effect of side airbags was considered by examining NASS. In near-side cases without airbag deployment, in crashes with delta-V’s close to NCAP (43 to 63 kph), the incidence of pulmonary contusion was 2.52%. In comparison, the near-side cases with airbag deployment had a pulmonary contusion rate of 2.22%, a 14% decrease. This difference is small; however, pulmonary contusion rates with side impact airbags should be studied further. These types of correlations can be used in the future to more accurately predict potential patient outcomes given basic crash characteristics. Since pulmonary contusion is based on an inflammatory response, the ability to predict possible outcomes would allow physicians to develop an appropriate treatment plan that focuses on the prevention of more severe outcomes, such as ARDS, through early interventions in high risk patients.