Fig. 3. Arterial blood concentrations of methoxycarbonyl etomidate's carboxylic acid metabolite (MOC-ECA) before the closed-loop infusion (Infusion Start) is started, when the burst suppression ratio is first reached 80% (BSR 80%), at the end of the infusion (Infusion End), and intermittently after the infusion is complete. *P < 0.05, **P < 0.01, ***P < 0.001 versus  corresponding 5-min infusion value assessed using a two-way analysis of variance followed by a Bonferroni posttest where the factors were time and methoxycarbonyl etomidate infusion duration. There were no significant differences in MOC-ECA concentrations at analogous times with 15- and 30-min infusions. All data represent the mean ± SD from four rats.