Could anti-inflammatory actions of catecholamines explain the possible beneficial effects of supranormal oxygen delivery in critically ill surgical patients?

Objective:To evaluate the literature regarding antiinflammatory actions of cytokines, evaluate randomized controlled trials (RCTs) of supranormal oxyg en delivery, and suggest alternative mechanism(s) for possible beneficial e ffects of supranormal oxygen delivery in critically ill surgical patients. Design: Literature review using Medline and review of selected illustrative studies. Main results: Catecholamines (epinephrine, norepinephrine, isoproterenol, a nd dopamine) in general inhibit tumor necrosis factor-alpha (TNF) productio n and may enhance interleukin-6 (IL-6) and IL-10 production. Phosphodiester ase inhibitors also inhibit TNF and may enhance IL-10. All studies used mod els (cell, animal, or humans infused with endotoxin) of sepsis. RCTs of sup ranormal oxygen delivery show decreased mortality in high-risk surgical pat ients; however, prevention or reversal of tissue hypoxia may not be the mec hanism of benefit. Antiinflammatory effects of catecholamines are a potenti al and, to date, unexplored mechanism of the benefit of supranormal oxygen delivery in critically ill surgical patients. Conclusions: Catecholamines may modulate cytokine response beneficially and could be a mechanism of decreased morbidity and mortality of supranormal o xygen delivery in high-risk surgical patients.