To investigate the potential of synchronization of pulsatile extracorporeal life support (p-ECLS).
Five calves (60±21 kg) were instrumented and subjected to partial femoro-femoral veno-arterial ECMO. Heart rate was synchronized to pump-ejection by a custom made pacemaker system. The cardiac-to-pump ejection delay was varied in 50 ms steps along the cardiac cycle. Data analysis focused on cardiac workload and peripheral perfusion.
Based on LV afterload (PLVpeak) three markers were identified in each animal: Maximum increase (I), mean (II), and maximum decrease (III) of afterload (see Figure 1and 2). The Table shows that systolic arrival of the p-ECLS pulse increased LV afterload (I). Elevated LV afterload is associated with an increase in PVA (oxygen consumption) and a decreased ventricular efficiency (EW/PVA). The diastolic coronary flow fraction during diastolic arrival (III) is about twice as high as during systolic arrival. Among the subjects the fraction of total peripheral flow delivered by the LV varied substantially (Table). Figure 1 and 2 show the delay dependency of multiple hemodynamic variables in two distinct cases of LV contribution. The balance between peripheral (and coronary) perfusion and cardiac workload can be improved by avoiding systolic pulse arrival (Figure 1 and 2).
During partial pulsatile ECLS ventricular efficiency can be improved upto 30 percent by avoidance of systolic impairment. Synchronization is more effective in subjects with a small left ventricular contribution to total peripheral flow.
Well-adjusted pulsatile extracorporeal life support may be more versatile than asynchronous or continuous systems in facilitating recovery of cardiac function.
L. Sauren, None.