Dynamic Arterial Elastance During Experimental Endotoxic Septic Shock: A Potential Marker of Cardiovascular Efficiency

Abstract

Dynamic arterial elastance (Ea_dyn), the ratio between pulse pressure variation (PPV) and stroke volume variation (SVV), has been suggested as a dynamic parameter relating pressure and flow. We aimed to determine the effects of endotoxic septic shock and hemodynamic resuscitation on Ea_dyn in an experimental study in 18 New Zealand rabbits. Animals received placebo (SHAM, <i>n</i> = 6) or intravenous lipopolysaccharide (E. Coli 055:B5, 1 mg⋅kg <b>^-</b> ¹) with or without (EDX-R, <i>n</i> = 6; EDX, <i>n</i> = 6) hemodynamic resuscitation (fluid bolus of 20 ml⋅kg <b>^-</b> 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). Ea_dyn increased in septic animals (from 0.73 to 1.70; <i>p</i> = 0.012) and dropped after hemodynamic resuscitation. Ea_dyn was related with the %Osc and EER [estimates: -0.101 (-0.137 to -0.064) and -9.494 (-11.964 to -7.024); <i>p</i> < 0.001, respectively]. So, the higher the Ea_dyn, the better the cardiovascular efficiency (lower %Osc and EER). Sepsis resulted in a reduced %Osc and 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.