Hypocalcemia in Trauma Patients

Have you ever wondered what is happening pathologically to your hypovolemic trauma patient? You know they’re losing a lot of blood but what else could they be losing? Calcium! Calcium enters your cardiac muscle cells and helps with the electrical signal. This mineral also plays a role in myocardial contraction. There are two types of calcium; serum calcium and ionized calcium. For this discussion, we will be focusing on ionized calcium. Ionized calcium is also known as free calcium because this type of calcium is not attached to proteins within the body. The normal range for ionized calcium is 4.4 to 5.2 mg/dL, with a critically low calcium being classified as <3.6 mg/dL. Calcium is important for the bones, teeth, and heart but it also plays a role in platelet adhesion! It helps your body form clots! With previously mentioned, I think we can easily identify why calcium plays a crucial role in our trauma patients. Let’s take a quick look at the clotting process.

Your blood has 12 factors: Factor I, II, III, IV, V, VII, VIII, IX, X, XI, XII, XIII. There are thirteen numerals and only twelve factors because factor VI was found to be a part of another factor (Activated Factor V). Each specific clotting factor has a job and these factors work together to make threads of protein called fibrin. Fibrin is signaled in your body when you are bleeding. Fibrin is formed from the protein fibrinogen which is produced by the liver and found in blood plasma. When your body sends its blood loss signal, the fibrinogen is converted into fibrin at the source of the bleed by an action called thrombin (thrombin is what causes fibrinogen to convert into fibrin).

Image Courtesy of Nurseyourownway.com

Trauma induced coagulopathy is phenomenon that occurs when the body can’t clot effectively. Calcium plays a huge role in the regulation of the coagulation cascade which is paramount in the maintenance of hemostasis. Other than platelet activation, calcium ions are responsible for complete activation of several coagulation factors, including coagulation factor XIII. When a patient is exsanguinating, they’re inevitably losing calcium and the ability to clot. In reference to blood transfusions, we need to note that blood banks use a chelating agent to bind the calcium so the blood won’t clot in the bag. Approximately each unit of blood contains 3gm of citrate, this amount is usually cleared from the body within approximately 5 minutes by the liver. When a patient has experienced significant trauma and needs multiple units of blood, this will compromise the liver and subsequently decrease citrate elimination. This ultimately leads to high levels of citrate which binds to the patient’s calcium and causes it to become inactive. This results in hypocalcemia. Therefore, the frontline treatment is calcium administration.

Remember the lethal trauma triad? HYPOTHERMIA, COAGULOPATHY , and ACIDOSIS. All three of these things can affect your patient’s chances of surviving. Hypothermia can cause a decrease in clotting factors and platelet function. Acidosis can cause an acceleration in fibrinogen degradation. Lastly, coagulopathy can cause a change between clotting, anti-coagulation and fibrinolysis (the breakdown of the fibrin in blood clots). After learning more about calcium and the importance of calcium’s functions and roles, should we be focusing on calcium as well?

Here is a post on why normal saline is terrible for trauma patients and is the equivalent to administering battery acid to them:

This site is meant to be used for educational use only. We strive to push evidence based medicine with no bias to help you obtain all the important information. You should always follow your protocols that have been set in place.

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-Jesse Duncan NR-P and Scopeducation Team (Ryan and Matt)

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