Plasma cytokine levels during hypoxic, normoxic, and hyperoxic endotoxeimia. Data are represented as median with interquartile range of 10 subjects per group. Gray box indicates period of oxygen status adjustment. P-values represent separate comparisons of the hypoxia and hyperoxia group with the normoxic group (two-way ANOVA-repeated measures [interaction term] on the log-transformed data). BL:baseline.