[Post-traumatic imbalances of plasma amino acids--interference factors or defense mechanisms? A study of protein metabolism in severe craniocerebral trauma].

This prospective study examined 44 patients with severe brain injury (33 survivors, 11 non-survivors), in order to clarify the question whether plasma amino acid deviations should definitively be considered detrimental or if this process might be part of a defense mechanism. Over an 8 day follow-up period the nitrogen balance, urea production, creatinine and 3-methyl-histidine excretion, as well as the plasma aminogram were determined. The survivors as the less traumatized group were compared to the non-survivors with higher-grad injuries. Most parameters showed no significant differences between the 2 groups. However, the non-survivors did reveal higher nitrogen losses primarily mobilized from muscle tissue. As a reaction to trauma a deviation from normal limits was found for the amino acid concentration which might facilitate to withstand the stress of injury. In contrast to the non-survivors, the survivors showed a much more increase of the total amino acid concentration as well as the concentrations of arginine, methionine and proline. It is concluded that these increases outside of normal limits must be a defense mechanism and therefore are not to be forced to the so-called normal values in the early posttraumatic period.