Pressure Infuser Bag and BP Measurement

[argos]

Is the BP reading affected when fluids are being infused by a pressure bag in the same arm? If so, please explain the mechanics or reference.

[CMags, MSN, RN]

Good question, my thoughts as an engineer prior to switching careers would be "minimally" - with the reasoning that the pressure infuser would raise venous pressure but that a bp cuff reads arterial pressure. Given the system as a whole is closed, there would be some increase but it would be distributed across a significant surface area hence "minimally". That's from a physics perspective but I'm curious as to those who have looked for this practically.

[argos]

My thinking exactly. Thanks for your perspective. I also have a little hydraulic engineering experience and was questioning a comment from a peer. I think they were perhaps confusing BP reading during CPR and the pressure bag. Cheers.

[Nalon1 RN/EMT-P, BSN, RN]

I would think not aside from the overall increase in volume being infused. The fluid flowing from the pressure bag while obtaining the B/P would not affect it.

As said, B/P measures the heart output pressure, not the returning pressure. Plus, what is the actual pressure of the fluid once it enters the vein? Just because you have the pressure bag @ 250 mmHg does not mean the pressure in the vein is anywhere near that.

I have to admit it is not something I ever thought about, probably because I never thought of the input pressure being any issue.

[offlabel]

"Is the BP reading affected when fluids are being infused by a pressure bag in the same arm? "

No, but that's a great way to blow an IV.