NITRIC-OXIDE PRODUCTION IN CRITICALLY-ILL PATIENTS

Objective-To measure serum nitrite and nitrate levels in critically il l children as indicators of endogenous nitric ride (NO) production. Hy pothesis-Endogenous NO production is increased in children with condit ions characterised by immune stimulation, Design-Prospective descripti ve study in a multidisciplinary paediatric intensive care unit. Patien ts-137 consecutive critically ill children with a variety of clinical conditions. Interventions-Using a rapid microtitre plate technique, da ily serum nitrite and nitrate levels were measured hom serum samples t hat remained in the clinical laboratory after daily routine phlebotomy . Clinical and laboratory information was also gathered daily for each patient. Results-The maximum serum nitrite plus nitrate levels (mu M) reached by children with infection (41.8 (SD 18.1)), sepsis syndrome (85.1 (39.9)), shock without sepsis (36.4 (19.1)), transplantation alo ne (61.0 (43.4)), transplantation with sepsis (200.7 (150.5)), or reje ction (161.7 (70.4)), were higher than in controls (18.1 (9.5)). In th e absence of exogenous NO donors, levels greater than 80 mu M were rea ched only in children with the sepsis syndrome, organ transplantation, or acute rejection. Conclusions-Increased endogenous NO production oc curs in children with clinical conditions associated with immune stimu lation. Further investigation is warranted to determine the value of t his simple and rapid test as a clinically useful diagnostic tool and t herapeutic monitor in the evaluation of children at risk for the sepsi s syndrome or acute allograft rejection.