ICU fluids

RN BSN 2009 · Dec 8, 2006

good luck on your exam!

texasnursingstudent · Dec 8, 2006

thanks "iceyspots." that's really nice of you :) i appreciate it.

nurseangel47 · Dec 8, 2006

Hi, texasnursingstudent:

Sorry I don't have that vault of knowledge in the ol' cranium...

Don't remember studying that way back in the day...been nursing since '86

Maybe if you look in your chemistry or lab value textbooks, it might have an entry in the glossary or the table of contents stating colloids, etc. that could lead you to the right section of said book?

Sorry I couldn't help. Good luck.

augigi, CNS · Dec 8, 2006

Good luck on your test.

Given the title of your post, you obviously know that colloids and crystalloids are solutions given to increase intravascular volume.

Crystalloids are defined as aqueous solutions of mineral salts or other water-soluble molecules. Colloids contain larger insoluble molecules, such as gelatin or albumin.

Crystalloids: Dextrose or saline solutions, Lactated Ringer's.

Colloids: Albumin, blood, synthetic albumins.

Basically as an overview, colloids tend to stay in the intravascular space, as they have much larger molecules in them, whereas crystalloids more easily pass into the tissues.

There is a huge ongoing debate as to the relative value of each solution in massive fluid resuscitation - the largest study to date, the SAFE study showed that there was no difference in outcomes with either saline or albumin solutions (I've attached it for you.)

The way you could test the response to the fluids depends on which solution you infuse: if you give blood, you could check the Hb/Hct to see the response; if you give albumin, you can check serum albumin levels to assess the response. Crystalloids would show in the change of blood chemistry - if you're giving saline, you'd check the sodium level, if you're giving dextrose you'd check the blood sugar level.

Hope that helps.

SAFE study.pdf

VickyRN, MSN, DNP, RN · Dec 9, 2006

Hi texasnursingstudent

Salt, electrolytes, glucose and other small molecular substances in solution are called crystalloids. Like a crystal, you can "see through" these solutions clearly. The most commonly used crystalloid solutions include normal saline (a solution of sodium chloride in water), lactated Ringer's solution, and dextrose in water. Isotonic crystalloid solutions (normal saline and lactated ringer's) will stay in the extracellular compartment (ECF). Since 25% of the ECF is intravascular fluid, 25% of the isotonic solution you infuse will remain in the blood stream; the rest will go into the interstitial spaces. So, if you infuse a quick fluid bolus of 1 liter NS, only 250 ml will remain in the intravascular space. With rapid infusions, you need to think about pulmonary edema occurring in susceptible clients (those with prior history of CHF or COPD). Dextrose in water is thought of as ‘free water’ - the dextrose is rapidly metabolized and the water is freely distributed to the cells; it does not specifically increase plasma volume.

Colloid dispersions are made up of large molecular-weight substances such as proteins (eg: albumin, gelatin) or carbohydrates (eg: starch, dextran). The colloidal particles are generally large molecules such as proteins or carbohydrates suspended in water. Although the particles are larger than those in a true solution, they are still small enough to remain evenly dispersed without settling. These types of preparations are more murky in appearance (similar to milk) and you can't see through them clearly. Colloids remain in the blood plasma longer than crystalloids. They do not readily cross capillary walls and can draw water from the interstitial space into the plasma, increasing its volume. Some colloids are made up of evenly-sized molecules, for example, albumin, while others have a variety of different molecule sizes and shapes, for example, starch.

In normal plasma, the plasma proteins (albumin, globulins, fibrinogen) are the major colloids present. The plasma protein albumin is very important in capillary fluid dynamics because it draws most of the fluid back into the distal ends of capillaries after it has been pushed out into the interstitial spaces by the hydrostatic pressure of the blood entering the capillary. Colloids act as water magnets – pull fluid back into the intravascular space. Will cause water to move from intracellular and interstitial into intravascular space. For this reason, albumin infusion is often of value in patients with cirrhosis, or in those at high risk of acute renal failure.

Colloids are a type of plasma expander. Albumin comes in two strengths: 25% and 5%. Other plasma expanders include dextran (complex synthetic sugar), hetastarch, and blood products (whole blood or packed red blood cells). Advantages: remain in intravascular space for hours. Disadvantages: risk of sensitivity reactions or there may be religious objections to their use (ie, blood products).

If a client is exsanguinating (bleeding out), PRBC's are the fluid resuscitation of choice. If not immediately available, then use NS until blood arrives.

Hope this helps :)

Daytonite, BSN, RN · Dec 9, 2006

colloidal iv solutions have high molecular weight. they do not pass through capillary walls very readily. by infusing colloids the osmotic pressure in the bloodstream is increased which results in fluid from other compartments being drawn into the vascular space and increasing vascular volume. colloids will stay in the vascular space longer than crystalloid solutions. albumin, dextran and hetastarch are colloids. you will see albumin given as a plasma volume expander to treat shock when there is blood or plasma loss, intestinal obstructions, edema, hypovolemia, burns, and chronic diseases like cirrhosis and nephrotic syndrome. blood protein can be measured by testing for serum albumin, serum globulin, total protein and protein electrophoresis. any other labs that would be ordered to diagnose the conditions listed would also be ordered, particularly tests to diagnose hemorrhage or hypovolemia. patients can develop fluid overload with infusion of albumin.

crystalloids are basically substances that are able to crystallize and can pass easily through capillary walls. basically, they are iv solutions that contain electrolytes. saline solutions are crystalloids. that pretty much includes most all the various strengths of saline and lactated ringer's. crystalloids are also used as volume expanders in emergency situations. they are cheaper to use than albumin and can be administered very rapidly, but usually more fluid is required than with colloids. the clinical effects of movement of the fluid into the cellular spaces must be taken into consideration since crystalloid solutions do not remain in the vascular space very long.

here are links that include a table of the commonly used iv solutions:'

http://www.nursewise.com/courses/iv_hour.htm - this article by a nurse includes information on electrolytes and what is contained in the various iv solutions along with some information on calculating iv rates.

http://www.muw.edu/nursing/iv.htm - iv fluids, the different types and why you would use them. includes information on colloids and crystalloids. also includes information on blood transfusion in the second half of the document.

since you are doing an icu rotation, you should also check out these websites:

http://rnbob.tripod.com/ - nurse bob's micu/icu survival guide

http://www.icufaqs.org/ - notes on icu nursing. links to icu procedures