Patients who received clonidine had greater augmented responses in AP to phenylephrine and in HR to isoproterenol ( 47.2 + / - 15.6 % vs 23.7 + / - 11.9 % for increase in systolic AP and 59.8 + / - 22.6 % vs 26.2 + / - 11.0 % for increase in HR , P < 0.05 respectively ) .
