Fig. 1. Composite left pulmonary vascular pressure–flow (LPQ) plots at baseline and after preconstriction with U46619 (*P < 0.01) in the conscious state and during propofol anesthesia. Compared with the conscious state, propofol had no effect on the baseline LPQ relation. The dose of U46619 was titrated to achieve the same degree of preconstriction in the conscious and propofol-anesthetized states.