Cryoprecipitate

Cryoprecipitate, also called cryo for short, is a frozen blood product prepared from blood plasma.^[1] Uses include hemophilia A, von Willebrand disease, obstetrical bleeding, and blood clotting problems.^[2] It is given by injection into a vein.^[3]

Cross-matching (compatibility testing) is not necessary and all ABO groups are acceptable for all people regardless of ABO types.^[1] It is made by thawing fresh frozen plasma to 1–6 °C then centrifuging and collecting the precipitate. This is then resuspended in a small amount of residual plasma (generally 10–15 mL) and is re-frozen for storage. It is often given to adults as two 5-unit pools instead of as a single product. It contains factor VIII. Instead of cryoprecipitate, specific clotting factor concentrates may be used. It can be stored at at least −18 °C for about a year.^[4] After thawing, single units can be stored at 20–24 °C for up to 6 hours. If units are pooled in an open system, they can only be held at 20–24 °C for up to 4 hours.^[4] It cannot be re-frozen after it is thawed for use.

It is on the World Health Organization's List of Essential Medicines.^[3]

Medical uses

Medical uses for giving cryoprecipitate include:^[5]

• Hemophilia – Used for emergency back up when specific factor concentrates are not available.
• von Willebrand disease – Not currently recommended unless last reserve. ddAVP is first line, followed by factor concentrates.
• Hypofibrinogenaemia (low fibrinogen levels), as can occur with massive transfusions
• Afibrinogenemia
• Bleeding from excessive anticoagulation – Fresh frozen plasma contains most of the coagulation factors and is an alternative choice when anticoagulation has to be reversed quickly.
• Massive haemorrhage – RBCs and volume expanders are preferred therapies.
• Disseminated intravascular coagulation
• Uremic bleeding tendency
• Reversing tPA (with aminocaproic acid)

Side effects

Side effects may include hemolytic transfusion reactions, febrile non-hemolytic reactions, allergic reactions (ranging from urticaria to anaphylaxis), septic reactions, transfusion related acute lung injury, circulatory overload, transfusion-associated graft-versus-host disease, and post-transfusion purpura.^[6]

Mechanism of action

Each unit (around 10 to 15 mL) typically provides:^[7]

• Fibrinogen 150–250 mg with a half-life of 100–150 hours
• Factor VIII 80–150 U with a half-life of 12 hours
• Factor XIII 50–75 U with a half-life of 150–300 hours.
• von Willebrand factor 100–150 U with a half-life of 24 hours

Cryoprecipitate also contains fibronectin; however there are no clear indications for fibronectin replacement.

US standards require manufacturers to test at least four units each month, and the products must have a minimum of 150 mg or more of fibrinogen and 80 IU of factor VIII.^[4][8] Individual products may actually have less than these amounts as long as the average remains above these minimums. Typical values for a unit are substantially higher, and aside from infants it is rare to transfuse just one unit.

History

While the method for the creation of Cryo was discovered by Judith Graham Pool from Stanford University in 1964,^[9] it was initially approved in 1971 in the United States under the name Cryoprecipitated AHF for the Hoxworth Blood Center University of Cincinnati Medical Center.^[10]

References

External links