Temporal trends of circulating nitric oxide and pro-inflammatory cytokine responses ex vivo in intra-abdominal sepsis: results from a cohort study

To evaluate the association of pro-inflammatory mediators with organ dysfunction and adverse outcome in intra-abdominal sepsis patients.

Twenty-one patients admitted to the Intensive Care Unit (ICU) were prospectively included in the study. Only patients with surgical diagnosis of intra-abdominal sepsis were enrolled.

Tumor necrosis factor-α (TNFα) and interleukin (IL)-6 produced ex vivo were significantly lower in non-survivors on admission (p = 0.021) and day 2 (p = 0.013), respectively. Nitric oxide (NO _x ) levels were significantly higher in non-survivors from the onset of sepsis and until day 4 after diagnosis (p < 0.05). Circulating lymphocyte counts were lower in non-survivors after admission over time, but there was no association with impaired cytokine production in this group of patients during the entire follow-up. All non-survivors developed nosocomial pneumonia concomitantly with multiple organ dysfunction and septic shock. There was a significant correlation between nitric oxide (NO _x ) concentrations and the sequential organ failure assessment (SOFA) score at day 2 (r = 0.598, p = 0.009), and ICU stay (r = 0.605, p = 0.006). Continuously high NO _x levels correlated with organ failure. The pro-inflammatory mediators TNFα, IL-6 and NO _x , and also the Simplified Acute Physiology Score II (SAPS-II), discriminate survivors from non-survivors. According to logistic regression models, although these parameters are independently associated with the outcome, they do not improve the predictive power of the SAPS-II score for mortality risk.

Disturbances in inflammatory responses and increase in NO _x generation seem to characterize early intra-abdominal sepsis, in which immune suppression is associated with an increased susceptibility to nosocomial infections. Sequential NO _x determinations could be a useful approach for improving the management of patients with intra-abdominal sepsis.