Fig. 4

a Typical recordings of left ventricular pressure (LVP), arterial pressure (AP), and right ventricular pressure (RVP) in response to rapid infusion (2 mL/kg, 1 mL/s) of 9 % NaCl solution. Doppler echocardiography images show blood velocity in the pulmonary artery before (Pre-infusion) and after (Post-infusion) rapid infusion of 9 % NaCl solution. Changes in the mean pressure difference between right ventricular pressure and the left atrium (b), mean pulmonary blood flow (c), and mean resistance in the pulmonary circulation (d) before (Pre-infusion) and after (Post-infusion) rapid infusion (2 mL/kg, 1 mL/s) of 9 % NaCl solution. *P < 0.05 versus pre-infusion. e Changes in positive and negative dP/dt max before (pre-infusion) and after (post-infusion) rapid infusion (2 mL/kg, 1 mL/s) of 0.9 % (solid bar) or 9 % NaCl (open bar) solution. *P < 0.05 versus pre-infusion