Figure 1. Invasive and non-invasive arterial pressure recordings at baseline and during phenylephrine infusion.

A, beat-to-beat mean blood pressure (MBP) from a subject at baseline and during phenylephrine at 2 μg kg⁻¹ min⁻¹. B, averaged power spectra from 4 subjects. Continuous lines are from the arterial line recordings. Dotted lines are from the Finapres. Similar data were observed during 0.5 and 1 μg kg⁻¹ min⁻¹ infusion.