The Impact of Pump Settings on the Quality of Pulsatility

The study objective was to evaluate the Jostra HL-20 roller pump under different baseflow and pump head settings with quantified energy values from pressure and flow waveforms, in a simulated pediatric bypass circuit. Pump flow rate was set at 800 mL/min for both pulsatile and nonpulsatile perfusion modes and the mean arterial pressure (MAP) of the pseudopatient was maintained at 40 mm Hg for each experiment. Pulsatile baseflow settings and pump head start points varied with each experiment. Pressure and flow waveforms were recorded at preoxygenator, precannula, and postcannula sites under each pump setting. A total of 91 experiments were performed (n = 7, nonpulsatile; n = 84, pulsatile). Increasing baseflow caused decreases in the mean circuit pressure and surplus hemodynamic energy (SHE) levels for all pump head start times. When increasing pump head start time within each baseflow, values for MAP and SHE increased significantly. Regardless of baseflow or pump head start time, values for mean circuit pressure and SHE were lower for nonpulsatile flow than for pulsatile flow. Total hemodynamic energy values were also significantly higher under pulsatile perfusion and increased pump start times while decreasing with increased baseflows in the circuit. This study concludes that decreased baseflows with increased pump head settings on the Jostra HL-20 roller pump could significantly increase quality of generated pulsatile energy. Further research is necessary to evaluate these various pump settings under microembolic loads and with different circuit components. ASAIO Journal 2009; 55:100-105.