How Does Pressure Affect Blood Transfusion from an Inverted Glass Bottle?

[WY]

Hi,

I have been looking at some discussion questions in a textbook and there is a question about blood transfusion from inverted glass bottle rather than a flexible bag. The question" What would happen if blood were transfused from an inverted glass bottle rather than a flexible bag?

I was thinking along the lines in the volume difference but then I think I am missing a link to or an idea to connect it to pressure and how the velocity of the blood coming out will change. Could it also be due to the air bubble it will have changing the pressure of the bottle of the inside compared to the outside thus stopping it from letting any more blood out? I'm not to sure what principles I need to look at to try and explain this to myself as I am a little bit confused.
Could someone help me straighten out what ideas i need to look at in particular?

Thanks in advance

 

[HallsofIvy]

The difference between a "bag" and a "bottle" is that the bag will collapse. As blood comes out of the bag, air pressure inside the bag is reduced so air pressure outside "collapses" the bag- result, air pressure inside becomes the same as air pressure outside (you are right- PV= nRT. n is decreasing but volume is also decreasing so P stays constant. Of course, it's the same as if there were NO bag there.)
As blood came out of a bottle, the air pressure inside the bottle would be reduced because "n" is decreasing. The bottle is rigid so V cannot change. Another way of saying that is that the air pressure outside is NOT "transmitted" to the blood. Pretty soon the pressure on the blood would drop below what is necessary for blood to come out.

When you are pouring water from a bottle, you hear the "glug, glug" because when the pressure inside the bottle becomes too low the water has to stop pouring long enough to allow air in the bottle to restablish the air pressure inside the bottle. Since a blood transfusion hose goes directly into a blood vessel, that can't happen.

 

[thepatientmental]

Hi there,

You are on the right track with thinking about the volume difference and pressure in the bottle. When blood is transfused from an inverted glass bottle, the volume of blood being transfused is limited by the size of the bottle. This means that the flow rate of the blood will be slower compared to using a flexible bag, which allows for a larger volume of blood to be transfused at a faster rate.

In terms of pressure, the air bubble in the bottle could play a role in regulating the pressure inside the bottle. As the blood is drained from the bottle, the air bubble will decrease in size, creating a lower pressure inside the bottle. This decrease in pressure could potentially slow down the flow of blood or even stop it altogether.

To better understand this concept, it would be helpful to look at the principles of fluid dynamics, specifically Bernoulli's principle. This principle states that as the velocity of a fluid increases, its pressure decreases. In the case of the inverted bottle, as the blood flows out at a slower rate, the pressure inside the bottle decreases, causing the flow to slow down even further.

I hope this helps to clarify the concepts you need to consider. Good luck with your studies!