Ascites versus Third-spacing

I’m confused about third-spacing.  I know that one of the possible symptoms of liver failure is called ascites, which I think is just fluid in the abdomen…is that right? But I also noticed when studying that you can have third-spacing in the abdomen during Congestive Heart Failure (CHF), too.  Is that the same thing as ascites?  So does that mean that ascites is a type of third-spacing?

Ascites is definitely a type of third-spacing. It can be seen in a variety of disease processes, including liver failure and CHF. Here’s a quick break-down of the three different kinds of fluid spacing:

1st spacing: Refers to all fluid that is where it is supposed to be, including fluid inside cells and inside the blood vessels.

2nd spacing: Refers to abnormal fluid accumulating in interstitial spaces. This fluid is NOT in the cells, and NOT in the blood vessels. But here is the important thing about 2nd spacing:  it is still ‘in contact’ with the areas it is supposed to be in, so that the fluid can easily move back into the 1st spacing areas if body conditions change.  Some of the factors that effect 2nd spacing will be hydrostatic pressure, diffusion, and osmosis.

3rd spacing: This is trapped fluid. Basically, this fluid is in a place in the body where it is difficult or impossible for it to move back into the cells or blood vessels without medical intervention.

The peritoneal cavity, which is where fluid accumulates in ascites, happens to be one of those locations where it is difficult for the body to reabsorb fluid.  That means that ascites IS a type of 3rd spacing.

One thing that I love about this student’s question is that I can tell that she’s really thinking about the material AND tying together concepts from different areas of her knowledge.  Even though she’s studying Congestive Heart Failure, she noticed some overlap with her knowledge of the symptoms seen during Liver Failure.  That’s awesome!  Not only will it help her to remember these symptoms in the future, but it will also make her a better nurse…a well-rounded nurse who is able to think independently.

8 thoughts on “Ascites versus Third-spacing”

  1. Schae

    I have a question on my online exam that refers to 1st, 2nd & 3rd space shifting terms? It asks for the definiton of 1st space shifting, 2nd and so on. Could you please confirm for me if the spaces you have mentioned here also refer to the shifting of these spaces? or is 1st space shifting – not a shift at all as you’ve mentioned above?

    Thank you!

  2. lisa lee

    Isn’t osmosis a first spacing? cause it is a normal exchange??

  3. lily

    Thank you! I have a fluid, electrolyte and pH exam in four days. Been unable to puzzle it out until now. Between this and my book I think I finally get it.

  4. Samantha

    Thanks for explaining this concept clearly and in plain english. It makes studying for my acute illness exam so much easier. You’re an excellent resource to help tie concepts together and solidify content. Thanks again.

  5. Brent Hatch

    This was the last place I had to look to understand the concept. Thank you for putting it clearly and simply.

  6. Jessica Bailey

    Thank you so much for this wonderful explanation!

    Thank you thank you!

  7. Jan

    Finally one clearly understandable explanation of spacing. I’ve made a list of causes of second and third spacing along with symptoms and treatment of hypovolemic shock

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