Blood pressure variability, heart functionality and left ventricular tissue alterations in a protocol of severe hemorrhagic shock and resuscitation

Autonomic control of blood pressure (BP) and heart rate (HR) is crucial during bleeding and hemorrhagic shock (HS) in order to compensate for hypotension and hypoxia. Previous works have observed that, at the point of hemodynamic decompensation, a marked suppression of BP and HR variability occurs, leading to irreversible shock. We hypothesized that the recovery of the autonomic control may be decisive for effective resuscitation, along with restoration of mean BP. We computed cardiovascular indices of baroreflex sensitivity, BP and HR variability by analyzing hemodynamic recordings collected from five pigs during a protocol of severe hemorrhage and resuscitation; three pigs were taken as sham control. Moreover, we assessed the effects of severe hemorrhage on heart functionality by integrating the hemodynamic findings with measures of plasma high sensitivity cardiac troponin T and metabolites concentrations in left ventricular (LV) tissue. Resuscitation was performed by fluids and noradrenaline and then b...