Medical IV's and flow

  • Thread starter wolf!
  • Start date
  • #26
15
0
yes, I understand that, what it does. my question is why.
Why does The piggyback bag produce a slighty higher pressure at the connection point due to its slighty higher elevation.
 
  • #27
5,439
9
It is well known that water tries to flow downhill.

So it is down hill from the upper bag to anywhere in the lower bag

The underlying driving force is gravity and we measure this tendency as pressure head which is the difference of elevation.
Downhill is the direction that makes this difference positive.
 
  • #28
15
0
so the reason for the higher bag draining first is not known at preset?
all that is known is that it happens?
 
  • #29
34,821
11,000
The reason is known and was explained ~5 times here in this thread.
The higher bag leads to a higher potential pressure at the connection, this leads to a higher outflow.
 
  • #30
8
0
so the reason for the higher bag draining first is not known at preset?
all that is known is that it happens?
Hi Wolf!, I'm a nurse, too. From reading this thread, I think I understand the answer. Think of it this way: Imagine a really long tube extending vertically that contains an entire liter of fluid. Now, imagine a shorter tube (same diameter) extending vertically that contains only 100mL of fluid. For all practical purposes, you may ignore the volume of the bags that the tubes are connected to... Think about the very tall column of water in the 1L tube with its higher weight, pressure, and 'desire' :-) to flow first. The fluid (column) in the lower, and thus 'less tall' tube will simply have to wait...

...does that help?
 

Related Threads on Medical IV's and flow

  • Last Post
Replies
1
Views
477
  • Last Post
Replies
3
Views
2K
  • Last Post
Replies
24
Views
3K
Replies
4
Views
443
Replies
1
Views
5K
  • Last Post
Replies
0
Views
1K
  • Last Post
Replies
2
Views
3K
  • Last Post
Replies
10
Views
4K
Replies
1
Views
607
  • Last Post
Replies
3
Views
156
Top