[Detection of NO liberation in the early phase of trauma]

Both, burn trauma and sepsis induce the generation of reactive oxygen intermediates which often coincides with increased nitric oxide (NO) levels. NO takes part in both circulatory disorders and cell protection. Therefore, in a prospective (pre-)clinical study we focused on the detection of NO in polytrauma patients (pts) starting as early as at the scene of accident. Upon approval of the local ethics committee, pts with an injury severity score (ISS) ranging from 9 to 75 (mean 22) were enrolled. Subsets were performed according to the different injury pattern (long bone fractures, head injury, polytrauma with and without damage to the thorax, isolated chest trauma). The first blood sample was obtained at the scene of accident. Then, blood was collected in hourly to daily intervals. NO production was assessed by the nitrate + nitrite plasma levels. To eliminate dilution effects following volume substitution, all values were recalculated on the plasma protein content. Immediately after trauma, NO plasma levels were elevated. This was most pronounced in pts that have experienced thoracic injuries irrespective of with or without additional polytrauma. There is evidence that NO production always starts immediately after major trauma but depends on the individual trauma pattern. In addition, the results reveal that lethal outcome is associated with an increased NO generation in the early post-injury period. We conclude that NO overproduction does not necessarily prime an overall protection in patients that have suffered from mechanical trauma. The role of NO after severe trauma and especially in thoracic injury should further be elucidated in a specific study on that topic.