Etomidate increases mortality in septic rats through inhibition of nuclear factor kappa-B rather than by causing adrenal insufficiency.

BACKGROUND: Both hyperinflammation during sepsis and etomidate can suppress adrenal function. In this study, we explored whether pretreatment with etomidate can relieve adrenal suppression and its impact on outcomes of cecal ligation and puncture (CLP)-induced septic rats.

MATERIALS AND METHODS: Rats (n = 18 per group) were divided in seven groups, including two control groups and treated with different combinations of a small pretreatment dose (0.6 mg/kg) and a large continuous dose (2 mg/kg/h over 2 h) of etomidate to evaluate the impact of the different administration combinations on the adrenal glands and outcomes in the septic rats. Animals (n = 8 per group) were euthanized at 24 h after CLP and blood samples and adrenal glands were then collected for further measurements. The remaining rats (n = 10 per group) were used to observe the 7-d survival rate post-CLP.

RESULTS: The survival rate (30%) was much lower in the group pretreated with a small dose before CLP surgery and followed by a large dose of etomidate than in the other groups. Etomidate decreased serum corticosterone, but not adrenocorticotropic hormone levels in septic rats, and also decreased serum tumor necrosis factor-alpha and interleukin-6 levels. In rat pretreated with a small dose of etomidate, the toll-like receptor-4 expression level in the adrenal glands was decreased and nuclear factor kappa-B (NF-kappa B) translocation was inhibited.

CONCLUSIONS: The mortality of septic rats and degree of adrenal injury caused by etomidate are not correlated. The etomidate-induced inhibition of inflammation and NF-kappa B translocation, which was more significant than adrenal suppression, may be responsible for the increased mortality in septic rats.