I’ll spend the next two posts discussing plasma. This is an important component of any trauma center’s massive transfusion protocol (MTP). Coagulopathy is the enemy of any seriously injured patient, and this product is used to attempt to fix that problem.
And now, there are two flavors available: liquid plasma and fresh-frozen plasma. But there is often confusion when discussing these products, especially when there are really three flavors! Let’s review exactly what they are, how they are similar, and how they differ.
Fresh frozen plasma (FFP)
This is plasma that is separated from donated whole blood. It is generally frozen within 8 hours and is called FFP. However, in some cases, it may not be frozen for a few more hours (not to exceed 24 hours total), and in that case, it is called FP24 or FP. It is functionally identical to FFP. But note that the first “F” is missing. Since it has gone beyond the 8-hour mark, it is no longer considered “fresh.” To be useful in your MTP, it must be thawed, which takes 20-40 minutes depending on the technique.
Thawed plasma
Take a frozen unit of FFP or FP, thaw it, and keep it in the refrigerator. Readily available, right? However, the clock starts ticking, and this unit expires after 5 days. Many hospital blood banks keep this product available for the massive transfusion protocol, especially if other hospital services are busy enough to use it as it approaches expiration. Waste is bad and expensive!
Liquid plasma (never frozen)
This is prepared by taking the plasma separated from donated blood and placing it in the refrigerator, not the freezer. Its shelf life is that of the unit of whole blood it was taken from (21 days), plus an additional 5 days, for a total of 26 days. This product used to be a rarity, but is becoming more common because of its longer shelf life than thawed plasma.
Finally, a word on plasma compatibility. ABO compatibility is still a concern, but Rh is not. There are no red cells in the plasma to carry any of the antigens. However, the plasma is loaded with A and/or B antibodies, depending on the donor’s blood type. So the compatibility chart is reversed compared to what you are accustomed to when giving red cells.
Remember, you are delivering antibodies with plasma and not antigens. So a Type A donor will have only Type B antibodies floating around in their plasma. This makes it incompatible with people with blood types B or AB.
Type O red cells are the universal donor type because they have no antigens on their surface. Since Type AB donors have both antigens on their red cells, they have no antibodies in their plasma. This makes AB plasma the universal donor type. Weird, huh? Here’s a compatibility chart for plasma.
Next time, I’ll discuss the virtues of the various plasma types used for massive transfusion in trauma.
