Assessment of the hemodynamic changes following fluid preloading in cardiac surgery

This prospective double-blind randomized study aims to study the hemodynamic changes following fluid preloading with Hydroxyethyl starch (HES) 6% (130/0.4) compared with normal saline (NS) in cardiac surgery patients.

Forty patients undergoing coronary artery bypass grafting (CABG) were enrolled in this study, then they were divided in 2 equal groups, HES and NS. After fast administration of 10 mL/kg from either solutions over 5 min only, hemodynamic parameters, such as heart rate, mean arterial pressure (MAP), central venous pressure (CVP), pulmonary artery occlusion pressure (PAOP), mean pulmonary artery pressure, systemic vascular resistance, and pulmonary vascular resistance were measured every 5 min for the total duration of 40 minutes.

There were significant differences in the cardiac index measurements between both groups at 15 min onward; also PAOP was significantly higher in HES group at 10 min onward. CVP was higher in HES group but statistically significant at 10 min only. MAP was higher in HES group, but that was statistically significant at 40 min only. On the other hand PAP was significantly higher at 10 and 40 min.

Fluid preloading with HES led to a significant increase in filling pressure of the left ventricle (PAOP) and cardiac index compared with NS. We believe that HES (130/0.4) could be a suitable solution for fluid preloading in CABG surgery patients. However, further studies are needed on different fluid preloading modalities with different dosing regimens.