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Crystalloids versus Colloids

Infusion Therapy is an awesome wonder when it comes to saving a patient’s life.  Is it really necessary to give a patient a Colloid versus a Crystalloid?

Trauma, burns, or surgery can cause people to lose large amounts of blood. Fluid replacement, giving fluids intravenously (into a vein) to replace lost blood, is used to maintain blood pressure and reduce the risk of dying. Blood products, non-blood products or combinations are used, including colloid or crystalloid solutions. Colloids are increasingly used but they are more expensive than crystalloids and there are many scientific studies show no evidence colloids reduce the risk of dying compared with crystalloids.

Background
Fluid resuscitation for hypovolemia and other medical issues is common practice in the management of critically ill patients, whether as a result of trauma, burns, major surgery, dehydration, or sepsis. 
Colloids have been widely used all over the country for quite some time and volume replacement with colloids is considerably more expensive than with crystalloids.
In the early 1860's, it was the investigation by Thomas Graham’s that led him to classify substances as crystalloids or colloids based on their ability to diffuse through a parchment membrane. Crystalloids passed readily through the membrane, whereas colloids did not. Intravenous fluids are similarly classified based on their ability to pass through barriers separating body fluid compartments, particularly the one between intravascular and extravascular (interstitial) fluid compartments.

CRYSTALLOIDS

According to the Taber’s Medical Dictionary, a Crystalloid is a solution in which crystals can or may form; but is able to diffuse across cellular membranes. Crystalloids are the most common fluids used in the healthcare setting. The following are some examples of the most common solutions in the crystalloid category.
• Normal Saline
• Lactate Ringers
• Dextrose 5%
 
Normal Saline
Normal Saline is composed of 154 mEq/L of Sodium and 154 mEq/L  of Chloride. The ph is 6.0 and the osmolarity is approximately 308. Normal saline is the main solution of choice when administering a blood product. (Raoof, George, Saleh, & Sung, 2008)
Lactate Ringers
Lactated Ringers is composed of 130 mEq/L of Sodium, 4 mEq/L of Potassium, 109 mEq/L of Chloride, and 28mEq/L of Lactate. The pH is approximately 5.1 and the osmolarity is approximately 273. (Raoof, George, Saleh, & Sung, 2008)
Dextrose 5% in Water
Dextrose 5% is consists of 278 mmoL/L of dextrose. The pH is 4.0 and the osmolarity is around 272.
D5W is considered an isotonic solution in the bag, but once administered the glucose is metabolized and the tonicity of the infused solution decreases in proportion to the osmolarity or tonicity of the non-dextrose components (electrolytes) within the water.

COLLOIDS

According to Tabers Medical Dictionary a colloid is a “glue-like substance, such as a protein or starch… or a substance used as a plasma expander in place of blood.” (Wilbur, 2009) The following are some examples of colloid solutions.
• Albumin
• Hetastarch
• Dextran

Albumin
Albumin is produced in a couple of varieties; typically 5% and 25%. Albumin “is made from pooled human plasma, which undergoes ethanol fractionation, ultra filtration, and pasteurization.”
Albumin 5% contains no preservative and is a clear, slightly viscous liquid; it is almost colorless or slightly yellow tint. It is mainly used to expand the intravascular volume whereas Albumin 25% is typically used for hypoproteinemia. Albumin 5% is composed of 154 mEq’s of Sodium and 50 grams of Albumin and has a pH level of 6.6 as well as an osmolarity of 290.
Hetastarch (Hespan)
Hetastarch is another type of plasma expander and is similar in properties to Albumin. If given; it can sometimes cause an increase in the serum Amylase; which may throw healthcare professionals for a loop into thinking the patient may be suffering from pancreatitis. Hetastarch is composed of 154 mEq’s of Sodium with a ph level of 5.5 as well as an osmolarity of 310.
Dextran
Dextran is also a plasma expander; however, it is higher in molecular weight than Hespan. The amount of expansion it provides to the vascular system depends on the amount and rate of infusion. Just like with Albumin; Dextran is provided in a couple strengths; typically 40 or 70. Dextran 40 is composed of 154 mEq’s Sodium, a ph level of 6.7, as well as an osmolarity of 320. Whereas Dextran 70 is composed of 154 mEq’s Sodium, a ph level of 6.3, and an osmolarity of 310.


Crystalloids versus Colloids

So, what is the best choice for fluid resuscitation?  The problem is it takes a larger amount of crystalloids to resuscitate a patient fully; on the other hand it only takes a small amount of colloids. Colloids however are more expensive and can expand the intravascular space fairly rapidly. Depending on what the patient’s medical condition is and the end goal of the fluid resuscitation will depend on whether the healthcare provider administers a crystalloid or colloid. For example if a patient arrives to the emergency room or ICU and as in hypovolemic shock; the goal of fluid replacement would most likely be attained by administering a crystalloid. If the patient is septic and has been diagnosed with septic shock the provider may give a colloid or crystalloid.

Final Thoughts

There is no evidence from randomized controlled trials that resuscitation with colloids reduces the risk of patient death, compared to the resuscitation with crystalloids, in patients with trauma, burns or following surgery. So this could help us conclude that the use of colloids may not only increase mortality; but they are also not associated with an improvement in survival and are considerably more expensive than crystalloids. It is hard to see how the continued use of colloids in clinical practice can be justified.

The FDA has also recently issued black box warning and safety updates with the use of  Hespan. 

See below the information released by the FDA regarding Hespan, you may Click Here to view the information in its entirety from the FDA website.

On November 25, 2013, the U.S. Food and Drug Administration (FDA) approved changes to the prescribing information for the class of hydroxyethyl starch products to add a newBoxed Warning about the risk of mortality and renal replacement therapy.  The revised labeling also includes updates to the Contraindications, Warnings and Precautions as well as the Adverse Reactions and Clinical Studies section.

Summary of Safety Issues

Hydroxyethyl starch (HES) solutions are used for the treatment of hypovolemia (low blood volume) when plasma volume expansion is desired.  Recent data have associated administration of these products with an increased risk of severe adverse events when used in certain patient populations.

Recommendations for Patients

Patients should be aware of the risks associated with the use of HES solutions and discuss these risks with their healthcare provider.
  • Be aware that severe kidney damage has been associated with the use of HES solutions.
  • Be sure to follow up with your healthcare provider as requested and follow all instructions.  Report any unusual symptoms immediately.
  • Symptoms of kidney damage can include:
    • change in the frequency, amount, or color of urine
    • blood in the urine
    • difficulty urinating
    • swelling of the legs, ankles, feet, face, or hands
    • unusual weakness or fatigue
    • nausea and vomiting
    • shortness of breath
Recommendations for Health Professionals
  • Do not use HES solutions in critically ill adult patients, including those with sepsis.
  • Avoid use in patients with pre-existing renal dysfunction.
  • Discontinue use of HES at the first sign of renal injury.
  • Need for renal replacement therapy has been reported up to 90 days after HES administration.  Continue to monitor renal function for at least 90 days in all hospitalized patients.
  • Monitor the coagulation status of patients undergoing open heart surgery in association with cardiopulmonary bypass as excess bleeding has been reported with HES solutions in this population.a Discontinue use of HES at the first sign of coagulopathy.
  • Do not use HES products in patients with severe liver disease.
  • Monitor liver function in patients receiving HES products.
Hespan (6% HES 450/0.7 in 0.9% Sodium Chloride Injection) is not recommended for use as a cardiac bypass pump prime, while the patient is on cardiopulmonary bypass, or in the immediate period after the pump has been discontinued because of the risk of increasing coagulation abnormalities and bleeding in patients whose coagulation status is already impaired.

Excess bleeding

In a meta-analysis of 18 RCTs in patients undergoing open heart surgery in association with cardiopulmonary bypass,15 use of different HES products, irrespective of molecular weight or degree of molar substitution, was associated with increased bleeding.  FDA considers excess bleeding a class effect warranting addition of this new safety information to the Warning and Precautions Section of the PI.

This blog was originally posted on Central Valley Medical's blog, by Kevin Stansbury.  Click Here to read this and other blogs from Kevin Stansbury.

Kevin Stansbury, MBA, BS, RN, VA-BC, is a Registered Nurse with over 25 years experience in the medical field including critical care, emergency medicine, and infusion therapy. He is currently living and working in the Central Valley of California. Kevin is a 13-year veteran of the U.S. Army where he served as a combat medic and nurse. He received several military decorations during his tours in Desert Shield and Desert Storm, including an Army Achievement Medal, an Army Commendation Medal, and the Kuwaiti Liberation Medal. Kevin also received his Expert Field Medical Badge while serving two tours in Korea.

Kevin is currently working as a registered nurse in the emergency room as well as working for Central Valley Medical. He is also a clinical instructor for IV Therapy, Basic Life Support (CPR), and EKG's. Kevin currently serves as a reviewer for the Journal of Infusion Nursing. He is a current member of the Infusion Nurses Society (INS), the Association for Vascular Access (AVA), and the Emergency Nurses Association (ENA.) He is also a sitting member on the board for the local network of AVA in the Central Valley also known as (CVAN). 

Kevin has written numerous online education courses for Pedagogy, to view his course listing click on his name above.

Posted: 1/13/2014 10:57:50 AM
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