Heartmate II

Hello,

I'm very new to caring for LVAD patients and am still trying to wrap my head around some of the basics. I was hoping someone might help clarify a few of them for me.

I had a patient the other night who at change of shift increased his flows & power while his PI remained stable. The flows had been about 5.4 - 5.9 overnight and he bumped up to 6.5 - 7. The PI remained unchanged. Not a huge change, but it took him outside of the ordered parameters. I was just wondering if someone could break down potential causes of increased power for me and what it can mean? I know the flows are just estimated based off the power and RPM's, and that clots are a possibility with an increase in power, however, I was told that these would also show a deviation in the PI. I'm a little unclear of the effect of fluid status, preload/afterload on the numbers. These changes were explained as the result of the carvedilol that the patient had been started on 3 days prior. Seems to make sense to me that with a high afterload, the watts would be higher to push against it, but apparently the opposite is true. Can someone explain to me how this works? Also if anyone has a simple explanation of PI I would really appreciate it, its still a little fuzzy for me as well.

Thank you!