Each unit of cryoprecipitate is prepared from one unit of fresh-frozen plasma. Each 10-to 15-mL unit contains at least 200 mg of fibrinogen along with factor VIII:C, factor VIII:von Willebrand factor, factor XIII, and ibronectin (American Association of Blood Banks, 2014). It is usually given as a "pool" or "bag" using an aliquot of ibrinogen concentrate taken from 8 to 120 donors. Cryoprecipitate is an ideal source of ibrinogen when levels are dangerously low and there is oozing from surgical incisions. Another alternative is virus-inactivated ibrinogen concentrate. Each gram of this raises the plasma fibrinogen level approximately 40 mg/ dL (Ahmed, 2012; Kikuchi, 2013).
This synthetic vitamin K-dependent protein is available as NovoSeven. It binds to exposed tissue factor at the site of injury to generate thrombin that activates platelets and the coagulation cascade. Since its introduction, rFVIla has been used to help control hemorrhage from surgery, trauma, and obstetrical causes (Goodnough, 2016; Murakami, 2015). Most Level I trauma centers include it in their massive transfusion protocols, and it is included in the one used at Parkland Hospital. Importantly, rFVIIa will not be efective if the plasma fibrinogen level is <50 mg/dL or the platelet count is <30,000/�L.
One major concern with rFVIla use is arterial-and to a lesser degree venous-thrombosis. In a review of 35 randomized trials with nearly 4500 subjects, arterial thromboembolism developed in 55 percent (Levi, 2010a). A second concern is that it was found to be only marginally efective (Pacheco, 2011).
This antiibrinolytic drug has been used for traumatic and obstetrical hemorrhage. Tranexamic acid inhibits clot lysis to help forestall bleeding by preventing plasmin from degrading ibrin. Its use has been associated with a higher incidence of renal cortical necrosis (F rimat, 2016). The evidence supporting its use as an adjunct in obstetrical hemorrhage is limited, and its routine use for prophylaxis is not recommended American College of Obstetricians and Gynecologists, 2017 d; Pacheco, 2017).
These function to speed blood product delivery to the bedside or operating room, which permits product infusion early in the resuscitation process. he rationale is to prevent adverse efects of aggressive resuscitation solely with crystalloid and packed red blood cells. That said, it is not necessary to activate massive transfusions until at least four to ive units of red cells have been given within 2 hours or so. Once activated, red cells, plasma, platelets, and fibrinogen are given by protocol in amounts shown in Table 41-9. Some protocols include rFVIIa and others include tranexamic acid.
As expected, studies attesting to the superiority for survival with massive transfusion protocols are limited. Most
TABLE 41-9. Parkland Hospital Obstetrical Massive Transfusion Protocol
No. 5 Units 3 Units 6-pack 1 Unit 2 mg rVlla = recombinant activated factor VII (NovoSeven).