Background and Purpose
Tissue perfusion during Basic Life Support (BLS) resuscitation depends on hemodynamic support provided by chest compressions. However, it remains unclear how the ischaemia/reperfusion phenomena influences hemodynamic stability during prolonged BLS. We aimed to study the arterial pressures and brain tissue perfusion in a porcine model of cardiac arrest (CA) and BLS.

Methods
Six female pigs (30± Kg) underwent an 8-minute non-treated ventricular fibrillation followed by BLS resuscitation for 15 (n=3) and 30 minutes (n=3). Chest compressions were provided with a LUCAS machine and respirations (FiO2 0.21) with bag valve mask at 30:2 ratio, respectively. Invasive systolic, mean and diastolic arterial pressures (SAP, MAP and DAP) and brain SrO2 were recorded every minute from baseline until the end of the experiment.  

Results
Briefly, arterial pressures rapidly dropped during 8-minutes untreated cardiac arrest and rapidly increased when BLS manoeuvres were started by LUCAS. SAP reached its peak at 3 minute and then was observed to gradually drop over-time. MAP and DAP were maintained low during BLS with also tendency to drop. Brain SrO2 during BLS did not correlate with the evolution of SAP, not showing any improvement once BLS manoeuvres began.

Conclusions
In a large-animal model of CA, arterial pressures drop over-time during the BLS despite mechanical chest compressions. Brain tissue perfusion does not follow arterial pressure pattern during BLS.

7 - Evolution of arterial pressure and brain SrO2 during Basic Life Support resuscitation in a translational model of cardiac arrest