FFP is collected in citrate-containing anticoagulation solution, frozen within 8 hours and stored at -30��C for up to 1 year. FFP contains all sellckchem of the clotting factors, fibrinogen (400 to 900 mg/unit), plasma proteins (particularly albumin), electrolytes, physiological anticoagulants (protein C, protein S, antithrombin, tissue factor pathway inhibitor) and added anticoagulants [1,2].Plasma frozen within 24 hours of collection is termed frozen plasma (PF24), containing 15 to 20% lower factor VIII levels than FFP [23,24]. PF24 is common in countries using the buffy-coat method, in which RBC and plasma are extracted after hard spin from whole blood and platelets recovered after a second soft spin within 24 hours of collection. PF24 has similar clinical indications as FFP [2,23,24].
FFP is commonly thawed in a water bath over 20 to 30 minutes, but US Food and Drug Administration-approved microwaves can thaw 2 units of plasma in 2 to 3 minutes [1]. After thawing, the activity of labile clotting factors such as factor V and factor VIII decline gradually, and most countries recommend FFP use within 24 hours [25,26]. In some countries, FFP is used up to 5 days after thawing. The consequences of transfusing stored, thawed 5-day-old plasma is not completely understood, but the activity of factor VIII is expected to drop by >50%, and the activity of factor V and factor VII drops to about 20% 5 days after thawing [27].Photochemically treated FFP and solvent detergent FFP are approved methods of inactivating pathogens in some jurisdictions. Both methods cause loss of clotting factors, particularly factor VIII.
Some solvent detergent FFP preparations have reduced activity of protein S and ��2-antiplasmin, and have been associated with thrombo-embolic complications [28,29]. These solvent detergent preparations are extensively used in some European countries, while solvent detergent FFP was withdrawn in North America due to concerns of Parvovirus transmission [1].RisksFFP can transmit infectious diseases, albeit rarely. Screen ing and pathogen inactivation reduced transmission rates of HIV to 1:7.8 million, of hepatitis C virus to 1:2.3 million and of hepatitis B virus to 1:153,000 units transfused [30]. In the UK, concerns over Creutzfeldt-Jakob disease – a rare but rapidly progressive spongiform encephalopathy – led to leukocyte depletion in all blood products and recommendations to use FFP from areas of low epidemicity [31,32].
Other important complications relate to blood immunogenicity, increasingly recognized over the past two decades, particularly transfusion-related acute lung injury (TRALI) and transfusion-associated circulatory overload [33,34]. TRALI is the commonest cause of transfusion-related death [33,34]. Two mechanisms have mostly been implicated in TRALI. Donor plasma antibodies react with human leukocyte antigens, causing complement AV-951 activation, endothelial damage, neutrophil activation and lung capillary leak.