Vitamin C status, oxidative stress, hyperglycaemia and endothelial function in critically ill patients with septic shock : an observational study
Septic shock is associated with oxidative stress, reduced levels of plasma vitamin C and stress hyperglycaemia – all factors that may influence endothelial, and therefore, organ function. Vitamin C is an important antioxidant in human plasma; and it has been implicated in maintaining normal endothelial function during oxidative stress. The vitamin C status of critically ill patients in South African ICUs has not been well investigated; neither has the relationship between vitamin C status, oxidative stress, hyperglycaemia and endothelial function been studied in this patient group. In a prospective, cross-sectional study investigating these factors in critically ill patients with septic shock on inotropic support, serial blood samples from 25 patients were taken at days zero and one, following inotrope initiation, and on day seven after inotrope cessation. These samples were analysed for plasma vitamin C, thiobarbituric acid-reactive substances (TBARS) - as a biomarker of oxidative stress - and soluble vascular cell adhesion molecule-1 (sVCAM-1), and E-selectin, as markers of endothelial dysfunction. The plasma glucose to vitamin C ratios were also calculated. Daily clinical measures in the patients included Sequential Organ Failure Assessment (SOFA) score, mean arterial blood pressure, blood glucose, fluid balance and inotropic support. The clinical outcomes were recorded.
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