Nitric oxide and active oxygen species in severe sepsis and surgically stressed patients.

To clarify how the kinetics of nitric oxide (NO) and active oxygen species are correlated with the occurrence of organ dysfunction in sepsis, the levels of monocyte-associated NO2, NO3, and active oxygen species were examined in severely septic patients with multiple organ dysfunction syndrome (group M; n = 5), and the results compared with those of postoperative patients who had undergone gastrointestinal surgery (group S; n = 5) and healthy volunteers (group C; n = 10). The production of NO2 and NO3 by monocytes was significantly higher in group M than in the other two groups, while the production of active oxygen species by monocytes was significantly higher in groups M and S, than in group C. A significant correlation between the production of NO2 and that of active oxygen species by monocytes was noted only in group M. These findings indicate that the simultaneous activation of NO and active oxygen species production by monocytes is a prerequisite for the onset of multiple organ dysfunction in severe sepsis.