Fig. 1.  Pressure-flow relations in control (Fio²0.40) and hypoxic (Fio²0.12) conditions before (baseline) and after normovolemic hemodilution with isotonic saline hydroxyethylstarch (NS-HES, A ) or hypertonic saline hydroxyethylstarch (HS-HES, B ). Standard deviations not shown for sake of clarity. PA = pulmonary artery. Hypoxia shifted the pressure-flow relation upward (P < 0.05). NS-HES and HS-HES did not affect the relation in control conditions and attenuated the response to hypoxia (P < 0.05).