Figure 3. Changes in hemodynamic variables from prehypercapnic values during the hypercapnia-120 (PaCO2, 120 mmHg), -80 (PaCO280 mmHg), and -60 (PaCO260 mmHg) in the control, clonidine-10, and clonidine-5 groups. CO = cardiac output; HR = heart rate; LV dP/dt = the peak of first derivative of left ventricular pressure; LVEDP = left ventricular end-diastolic pressure; MAP = mean arterial pressure; MPAP = mean pulmonary artery pressure; PVR = pulmonary vascular resistance; RAP = right atrial pressure; SVR = systemic vascular resistance. *P < 0.05 versus the prehypercapnic values. *P < 0.05 versus the control group. (section)P < 0.05 versus the clonidine-5 group.