Fig. 3. Effect of antioxidants on isoflurane- or sham isoflurane–induced alterations of the acute hypoxic response (AHR). Values are the ratio of the 95% confidence intervals of the antioxidant effect relative to isoflurane in session 1, the ratio isoflurane + placebo/isoflurane in session 2, and the ratio sham isoflurane + antioxidant/sham isoflurane in session 3. A value of 1 indicates no effect of the antioxidant or placebo on the (sham) isoflurane-induced effect on the hypoxic response. The confidence intervals of session 1 do not overlap with those of session 2 or 3.