Fig. 3. ( A ) Mean arterial pressure (MAP), ( B ) mean pulmonary arterial pressure (PAP), ( C ) systemic vascular resistance (SVR), ( D ) pulmonary vascular resistance (PVR), ( E ) cardiac output, and ( F ) plasma methemoglobin concentration of awake lambs after infusion of autologous whole blood (n = 6), intravenous HBOC-201 (n = 5), or HBOC-201 (12 ml/kg) after pretreatment by breathing 80 ppm nitric oxide for 1 h followed by continuously breathing 5 ppm nitric oxide for 2 h (high/low iNO, n = 6). * P < 0.05 HBOC-201 differs from autologous whole blood and from HBOC-201 after high/low inhaled nitric oxide. † P < 0.05; autologous whole blood differs from HBOC-201 with or without high/low inhaled nitric oxide. ‡ P < 0.05; HBOC-201 differs from autologous whole blood. § P < 0.05; differs from autologous whole blood and HBOC-201. HBOC = hemoglobin-based oxygen-carrying solution; iNO = inhaled nitric oxide.