Figure 2. Effects of leg elevation and phenylephrine (PE) on stroke volume (SV; upper panel), stroke work (SW; middle panel), and dP/dtmax(lower panel). For a similar increase in systolic pressure, a different response in SV, SW, and dP/dtmaxwas observed with leg elevation and phenylephrine. With leg elevation, SV, SW, and dP/dtmaxincreased in some patients, remained unchanged in others, whereas in the remaining patients, SV, SW, and dP/dtmaxdecreased. With phenylephrine, a homogeneous response was observed with no change in SV and an increase in SW and dP/dtmaxin all patients.