Background
Plasma expander (PE) based on polyethylene glycol (PEG) conjugated to albumin has shown positive results maintaining blood volume (BV) during hemodilution and restoring BV during resuscitation from hemorrhagic shock. PEG conjugation to human serum albumin (HSA), PEG-HSA, increasing size, weigh and colloidal osmotic pressure (COP), with minor effects on solution viscosity.
Methods
This study was designed to test the hypothesis that PEG-HSA (2 g/dL) produced by direct PEGylation chemistry improves cardiac function during two experimental models, i) moderate hemodilution and ii) resuscitation from hemorrhagic shock, compared to a conventional colloidal plasma expander (dextran 70 kDa, D×70, 6 g/dL). Cardiac function was studied using a miniaturized pressure volume (PV) conductance catheter implanted in the left ventricle (LV) and evaluated in terms of cardiac indices derived from the PV measurements.
Results
PEG-HSA increased cardiac output (CO), stroke volume (SV) and stroke work (SW), and decreased systemic vascular resistance (SVR) compared to D×70, in both experimental models. The improvements induced by PEG-HSA in cardiac function were sustained over the observation time. PEG-HSA cardiac mechanoenergetics changes are the result of increased energy transferred per stroke, and decreased resistance of the vasculature connecting the heart. In summary, PEG-HSA decreased LV ejection impedance.
Conclusion
Ejection of blood diluted with PEG-HSA presented a reduced load to the heart, increased contractile function, and lowered the energy consumed per unit volume compared to D×70. Our results emphasize the importance of heart function as a parameter to be included in the evaluation changes induced by new PEs.