What Are Intravenous Fluids?

Patients may receive fluids via an intravenous drip.
Intravenous fluids.
An intravenous insertion site on the forearm.
An IV is generally established by passing a hypodermic needle through the skin directly into a vein, usually located on the back of the hand, or closer to the elbow.
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  • Written By: Mary McMahon
  • Edited By: O. Wallace
  • Last Modified Date: 04 August 2014
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Intravenous fluids are fluids which are intended to be administered to a patient intravenously, directly through the circulatory system. These fluids must be sterile to protect patients from injury, and there are a number of different types available for use. Many companies manufacture packaged intravenous fluids, as well as products which can be mixed with sterile water to prepare a solution for intravenous administration.

Fluids are given when someone's fluid volume falls. There are a number of things which can cause a drop in fluid volume. Vomiting and diarrhea are a classic example, which is why people are encouraged to drink fluids when they are sick, to keep their fluid volume stable. Another cause is blood loss, which causes problems both because people lose blood products, and because they experience a loss in fluid volume. Electrolyte levels in the blood can also become unstable as a result of rapid changes in fluid volume, in which case intravenous fluids can be used to restore the balance.

Intravenous fluids can be broken into two broad groups. Crystalloids such as saline solutions contain a solution of molecules which can dissolve in water. When crystalloids are administered, they tend to create low osmotic pressure, allowing fluid to move across the blood vessels, and this can be linked with edema. Colloids contain particles which are not soluble in water, and they create high osmotic pressure, attracting fluid into the blood vessels. Blood is an example of a commonly administered intravenous colloid.

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Changes in fluid volume can cause changes in blood pressure, and a series of cascading reactions in the body. However, intravenous fluids are not always the solution. If the wrong fluid is administered, too many fluids are given, or a patient is not monitored, giving fluids can actually make the situation worse. For example, a patient may develop severe edema which can take some time to resolve as the body tries to express the excess water.

Intravenous fluids can also be used as a route of medication administration. If a doctor wants to deliver a small amount of medication over an extended period of time, it can be dissolved in a bag of intravenous fluids and set on an infusion pump which delivers the medicated fluid directly into the blood. They are also commonly used to assist with surgical recovery; people who receive fluids after surgery tend to experience better recovery than people who do not.

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anon309139
Post 7

Can too much fluids cause the electrolyte level to zero out? Can this also lead to a stroke?

anon290227
Post 5

What happens if fluids are given too rapidly?

anon195057
Post 4

I was in the hospital for dehydration and they gave me IV fluid, a saline chloride solution. Three days after the IV, I got a tingling sensation in my body, had severe pain and discomfort in my abdomen and I felt horrible. I asked my doctor what happened but he didn't say anything. I think the IV fluid made my body too acidic since ph of IV is 5.00. I think this can be dangerous if they don't know what kind of solution you should get into your body.

pharmchick78
Post 3

@pleats -- You're right, there are several kinds of common IV fluids, and they basically fall into four categories: fluids that expand the volume of the circulatory system; blood based products, as in transfusions, blood substitutes (just what they sound like), and medication.

Now within each one of those there are most commonly used products as well -- say ringer's lactate for volume expanders, etc.

You can also divide IV fluids into isotonic intravenous fluids, hypertonic intravenous fluids and hypotonic intravenous fluids. Isotonic IV fluids are those which remain between the cells in blood vessels; hypertonic fluids pull liquid from the cells, and hypotonic fluids go into cells.

And there are even natural versus synthetic divisions. So although there is a quick answer to your question -- "yes" -- it's a lot more complicated than just that.

pleats
Post 2

So what are some of the more common types of intravenous fluids? I am sure that there is some kind of "most common" IV fluid, but for the life of me I don't know what it is.

And what is @copperpipe talking about with an IV warmer? I didn't even know such things existed, but I guess it makes sense -- you don't want to have all that cold fluid running through your body; besides being uncomfortable, I bet that could cause some really serious health effects.

CopperPipe
Post 1

I wonder who first got the idea of intravenous fluids -- I mean, it seems throughout history that all you hear about medicine wise for the longest time is leeches and bleeding and purging -- basically taking fluid out of people rather than fluid resuscitation.

I can't imagine how whoever the inventor of the IV was got the idea of putting fluids into someone via their veins. And given how easy it is to mess up an IV, or cause an embolism, frankly, I can't see how it caught on.

But I'm sure glad it did though, seeing how many lives that intravenous fluid has saved over the years. I just hope that if I ever have to get any IV fluids then they are sure to heat up the blood warmer first!

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