Dynamic arterial elastance during experimental endotoxic septic shock

Abstract Background: Dynamic arterial elastance (Ea dyn ), the ratio between pulse pressure variation (PPV) and stroke volume variation (SVV), has been suggested as a functional parameter that is a surrogate of arterial load. We aimed to determine the effects of endotoxic septic shock and hemodynamic resuscitation on Ea dyn . Results: Experimental randomized study in a university animal research laboratory with 18 New Zealand rabbits. Animals received placebo (SHAM, n=6) or intravenous lipopolysaccharide (LPS, Escherichia coli serotype 055:B5, 1 mg·kg -1 ) with or without (EDX-R, n=6; EDX-NR, n=6) hemodynamic resuscitation (fluid bolus of 20 ml·kg -1 and norepinephrine for restoring mean arterial pressure). Continuous arterial pressure and aortic blood flow measurements were obtained simultaneously. Cardiovascular efficiency was evaluated by the oscillatory power fraction (%Osc: oscillatory work / left ventricular (LV) total work) and the energy efficiency ratio (EER = LV total work/cardiac output). The LPS-induced endotoxic shock produced a hyperdynamic shock with high cardiac output and arterial hypotension. Ea dyn increased in septic animals (from 0.73 to 1.70; p=0.012) and dropped after hemodynamic resuscitation. Ea dyn was related with the %Osc and EER [estimates: -0.101 (-0.137 – -0.064) and -9.494 (-11.964 – -7.024); p<0.001, respectively]. So, the higher the Ea dyn, the better the cardiovascular efficiency (lower %Osc and EER). Conclusions: In this experimental model, Ea dyn increased during endotoxic septic shock and decreased with hemodynamic resuscitation. Sepsis resulted in a reduced oscillatory power fraction and lowered EER, reflecting a better cardiovascular efficiency that was tracked by Ea dyn . Ea dyn could be a potential index of cardiovascular efficiency during septic shock.