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:'
- 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.
- 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:
- nurse bob's micu/icu survival guide
- notes on icu nursing. links to icu procedures