Air rate through needle with pressure gradient

Forum about flow calculators available on and how to find solution for your fluid flow problem.
Post Reply
Posts: 1
Joined: Tue Mar 12, 2013 7:33 pm

Air rate through needle with pressure gradient

Post by jasin629 » Tue Mar 12, 2013 7:45 pm


I'm trying to get a somewhat accurate value of air bubble rate through a needle into a blood vessel when a slight pressure gradient is present.
The venous system pressure near the heart can become negative depending on insertion location, patient position, and patient breathing causing air to be sucked into the vessel potentially causing an embolism.

When using the Hagen-Poiseulle equation, I think I'm calculating values which I can verify in the lab but I'm not sure about viscosity changes from air entering blood. I'm using air viscosity because i think it's worst case. Should I be using the Darcy equation instead?


Post Reply