air entering external jugular vein?

[scilearner]

Hello everyone,

 

If external jugular vein is damaged and is kept open, air can enter upon inspiration. I thought in inspiration air only travels to through trachea to lungs, so how can air enter the vein in inspiration. When we breathe, air only passes through trachea right, our whole body doesn't get it right (I know later by capilllaries in lungs but directly I mean) ? Thanks

[ewmon]

If external jugular vein is damaged and is kept open, air can enter upon inspiration.

You're right to feel confused. What would overcome the pressure pushing the blood out? And why only the jugular vein, why not a cut on the finger? I'm sure you've seen someone/yourself bleeding.

[cypress]

The jugular vein is large and goes directly to the heart. As such, the pressure is very low and can go into slight vacuum pulling air into it if it is damaged.

[ewmon]

What would cause the vacuum?

[scilearner]

Thanks for all the replies but my question is actually from where does the air come from. Is it air dissolved in interstistial fluid or air inside your body. I'm thinking that air inside your body is covered by lungs right? I think I have some misunderstandig. Please correct me Thanks

[ewmon]

The only such veins that I know are the pulmonary veins carrying oxygenated blood from the lungs to the heart. From where did you get the notion that air enters the jugular vein?

[scilearner]

The only such veins that I know are the pulmonary veins carrying oxygenated blood from the lungs to the heart. From where did you get the notion that air enters the jugular vein?

 

First of all thanks for the interest so far in the subject The book says if the lumen of EJV is kept open, air can enter in inspiration and cause fatal air embolism.

[ewmon]

I'd have to guess that "keeping the vein open" means having an IV needle that's open to the air. When someone inhales, it creates less than atmospheric pressure in the chest, which might affect the veins and arteries running into and out of the chest. Because of the less-than-atmospheric pressure in the vein, and if the vein did not simply collapse, air might enter through the IV. A few bubbles wouldn't do much, but sufficient amounts of air can cause death. This information sounds like a warning against allowing an air space in IV bags connected to jugular veins.

 

Although this air might oxygenate the blood, I cannot see this to be seriously viewed as "respiration", especially because the circumstances are contrived, impractical and unsustainable. If you enjoy such medical phenomena, this reminds me of the extraordinary case of Alexis St. Martin.