The functional inhibition of plasma kallikrein. A critical factor in septic shock.

Functional kallikrein inhibition and prekallikrein levels have been studied during septic shock and septicemia in 13 patients using chromogenic peptide substrate assays. Eleven septic shock episodes were studied of which 5 were fatal. Marked reductions in functional kallikrein inhibition and prekallikrein values occurred during fatal septic shock. In patients who could be resuscitated from septic shock, functional kallikrein inhibition was in the normal range, but significantly lower than in patients with septicemia only. Also in these two groups of patients decreased prekallikrein values were found. During treatment a gradual increase in prekallikrein was observed in the survivors and functional kallikrein inhibition values remained in the normal range during the whole course. Our results indicate that the functional inhibition of plasma kallikrein plays a major role in determining the outcome of septic shock.