Hi Chris, thank you.
If you have ever made or seen a “Cartesian Diver” or manually bled car brakes you can see why leg bag changes introduce air and why this is an issue. So from an engineering point of view for fun understanding the issue..? 😀
The small diameter catheter and the 300mm/5mm of pipe in the leg bag introduce a limited volume of compressible air into the “hydraulic system” as you swop bags and drain the catheter ( above the non return valve) If it was a central heating system it would be an unvented system not designed to have air within.
The air can get trapped in the catheter simply due to surface tension and will resist the poor fluid “Head” pressure from the bladder quite effectively, compressing and resisting the downward flow of urine as the air will compress, the fluid won’t . Bends and kinks will make this worse. Any air in the bladder will rise to the top of the fluid but the bladder is mainly empty as it’s drained so it will stay there and possibly effect the input tubes as well? (not much static fluid pressure to force the air out either?)
What the effect of air in your bladder is I can only guess, but I don’t think it’s normal or healthy if it builds up unchecked? Air in any fluid system allows movement or sloshing about of the fluid, that would not happen if fully filled. The dynamic pressure would also vary considerably especially if you are out exercising and change altitude as I have been. Pressures could spike higher than atmospheric under certain conditions within the bladder, not sure if this would be OK or not?
I have had blood twice, (OK immediately before on both occasions) and both times after changing the leg bag and exercising; the bag has failed to drain properly afterwards for a few hours and has been Mateus Rose. I have removed a large volume of air to clear the issue after and then OK. But loads of others haven’t had issues so??
I have had problems with fine tubes and pumped water cooling systems over the years, and it’s amazing what about 100mm of air in a small bore pipe can destroy, I don’t want it destroying me!
Anyway hopefully being removed on Thursday?😀
Oh!...pull-up pants and toilet training?
P.S The whole Catheter design is annoying me really!
Edited by member 06 Jan 2021 at 01:30
| Reason: Not specified