Figure 32-17 Arterial pressure gradients after cardiopulmonary bypass. A, Femoral and radial artery pressure traces recorded 2 minutes after bypass, when radial artery pressure underestimates the more centrally measured femoral artery pressure, and 30 minutes after bypass, when radial and femoral arterial pressures have been equalized and radial pressure has assumed a more typical morphology. Note that the dicrotic notch (arrows) is visible in the femoral pressure trace after bypass, but not initially in the radial pressure trace. B, Femoral and radial artery pressure traces recorded before cardiopulmonary bypass, 2 minutes after bypass, and 30 minutes after bypass. Note the changing relationship between femoral and radial artery pressure measurements at these different times.