Nitrogen Oxide Levels in Patients After Trauma and During Sepsis

The mediators responsible for maintenance of the hyperdynamic state and the low systemic vascular resistance (SVR) observed in sepsis have not been elucidated. Nitric oxide ( $$ N = O) is a mediator with numerous functions, including regulation of vascular tone and a role in macrophage-mediated cytostasis and microbiostasis. Thirty-nine critically ill trauma and septic patients were studied to determine the relationship between $$ N = O production and the hyperdynamic state. High plasma levels of NO2-/NO3- (the stable end products of $$ N = O) were observed in septic patients (p < 0.02). Low SVR and high endotoxin levels were associated with high NO2-/NO3- values (p = 0.029, p = 0.002). Changes in $$ N = O levels may mediate the vasodilation seen in sepsis. Low NO2-/NO3- levels were observed in trauma patients (p < 0.001) and remained low even in the presence of sepsis (p = 0.001).