Plasma catecholamines in severely injured patients: a prospective study on 45 patients with multiple injuries.

Plasma catecholamine levels were studied in 45 severely injured patients for 8 days after the trauma. Sixteen of the patients were classified as critically injured and 29 as seriously injured. The total plasma catecholamine values of the whole group immediately after the injury were almost twice as high as the eighth day reference values and remained significantly higher than these values for 6 hours after the trauma. On admission both the plasma adrenaline and noradrenaline levels were elevated. The plasma adrenaline levels on admission correlated with the blood volume replacement which was required within the first 6 hours. The plasma noradrenaline levels in the critically injured group were significantly higher throughout the observation period than in the seriously injured group. A corresponding difference was observed in the plasma adrenaline concentrations only during the first 12 hours. The results showed that strong stimulation of the sympathetic nervous system occurs in severely injured patients. Factors stimulating the sympathetic nervous system apparently included hypovolaemia, tissue hypoxia, acidosis and the pain produced by the trauma and therapeutic measures.