Figure 1. Cardiac output (mean plus/minus SD, n = 5) in the control and stroma-free methemoglobin groups of dogs at baseline, after intravenous administration of stroma-free methemoglobin in the stroma-free methemoglobin group, and at the end of the cyanide infusion. *Significant difference (P < 0.05) from baseline. (dagger)Significant difference (P < 0.05) from the stroma-free methemoglobin measurement.