Common VAD settings: Pulsatility index (PI) is a dimensionless measure of LV pulsatility, ranging from 1 to 10, with an average of 5 for the HeartMate LVADs. It is increased in the setting of adequate LV preload and suggests LV systolic augmentation and a low PI represents low preload or contractility. Increasing pump speed by decompressing the LV will typically decrease PI and vice versa. Once a normal PI range is determined for a patient, it should not vary significantly. Pump speed is determined to allow adequate LV preload for intermittent LV ejection and avoid suction events. A low speed can cause pump stasis and thrombosis, and a high speed can cause hemolysis, excessive LV decompression, and suction events, as well as RV dysfunction. Pump power, which typically correlates directly with pump speed, can be reduced secondary to inflow cannula obstruction or reduced LV preload. An increase in pump power without increased pump flow should raise suspicion for pump thrombosis.

References

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• Nicolosi AC, Pagel PS. Perioperative considerations in the patient with a left ventricular assist device. Anesthesiology. 2003;98:565-570.
• Stone M, Hinchey J, Sattler C, et al. Trends in the management of patients with left ventricular assist devices presenting for noncardiac surgery: a 10-year institutional experience. Semin Cardiothorac Vasc Anesth. 2016;20:197-204.