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3.2. Efficacy and safety

Each type of FFP has a spectrum of potential adverse effects; the decision on which to use may depend on specific clinical circumstances and availability.

3.2.1. MBFFP and SDFFP. 
Both pathogen reduction methods cause some loss of coagulation factors. MBFFP has relatively low FVIII and fibrinogen activity (Atance et al, 2001). These authors also claim reduced clinical efficacy. SDFFP has reduced activity of VWF and FVIII. It also has reduced functional activity of protein S (Jain et al, 2003; Yarranton et al, 2003).

3.2.2. MBFFP
Viral safety. There has been one possible, but not proven, case of HCV transmission from a single donor unit of MBFFP (Pamphilon, 2000). However, single donor products avoid the risk of pooling, which may cause 1 unit infectious for HCV or other non-inactivated organisms to infect many recipients.

Toxicological safety. Doses of MB that are much larger than the amount present in MBFFP are well established as a treatment for methemoglobinaemia (Mansouri & Lurie, 1993). There is no need for concern regarding patients with glucose-6-phosphate dehydrogenase deficiency (grade A recommendation, level I evidence).

3.2.3. SDFFP. 
Materials from different manufacturers may differ in detail and have different efficacy and safety profiles (Solheim & Hellstern, 2003). The reduced activity of protein S has been associated with the development of venous thromboembolism (VTE). Eight episodes in seven of 68 patients with TTP receiving plasma exchange were reported by Yarranton et al (2003). Jain et al (2003) have reported an association of SDFFP with thromboembolic complications in patients undergoing liver transplantation. Concern has been expressed regarding possible transmission of non-lipid-coated viruses by PRFFP. In the USA, batches have been withdrawn because of possible parvovirus B19 transmission. Suppliers now specify levels of HAV and B19 antibodies in the preparation, and may also define a cut off for B19 genomes. Studies of patients treated with SDFFP compared with FFP have not revealed excessive transmissions of non-lipid-coated viruses, but the number of patients studied is still small.

Recommendation
In any patient for whom PRP is being considered, the risks of HAV and parvovirus B19 transmission and their clinical sequelae should be weighed against the likely benefits (grade B recommendation, level II/III evidence).

4. Selection of FFP packs by blood group

The following recommendations have been updated from previous guidelines.

4.1. ABO blood group compatibility (see Table I)

Group O plasma is more likely to contain high titres of ABO antibodies than plasma from group A or B donors, although activities vary widely between donors. The UK Blood Services test all donations for ‘high-titre’ antibodies. Unreactive donations are labelled to indicate a relatively low risk of causing ABO-related haemolysis. Although there were no reports of ABO-associated haemolysis from FFP in the first 5 years of the SHOT scheme, in the year 2000 three patients of blood group A who received recovered pooled group O platelets suspended in plasma had haemolytic reactions; for one of these the platelets were obtained by aphaeresis and the plasma was not found to have high-titre haemolysins according to the testing criteria. Fresh-frozen plasma which is not of the same ABO group as the patient should only be used if it contains no high-titre anti-A and anti-B; it is preferable to use group A FFP for group B patients and vice versa where ABO-identical FFP is not available. However, as no in vitro test can always predict in vivo haemolysis, especially when large volumes are transfused, clinicians and hospital blood bank staff should be aware that haemolysis could occur with ABO-incompatible FFP. This includes plasma of group A given to patients of group B and vice versa, even if the donation has been tested and labelled ‘high-titre negative’ correctly according to the protocol. Group AB FFP can be used in an emergency if the patient’s ABO blood group is unknown, but is likely to be in short supply.

Recommendation
With regard to ABO blood groups, the first choice of FFP is that of the same ABO group as the patient. If this is not available, FFP of a different ABO group is acceptable so long as it has been shown not to possess anti-A or anti-B activity above a limit designed to detect ‘high titres’. FFP of group O should only be given to O recipients (grade B recommendation, level III evidence).

For infants and neonates, plasma should be free of clinically significant irregular blood group antibodies. FFP from group AB donors has no anti-A or anti-B antibodies, and is frequently preferred. 

Recommendation
Group O FFP should not be used in infants or neonates who are not group O because the relatively large volumes required can lead to passive immune haemolysis (grade B recommendation, level III evidence).

4.2. Rh blood group compatibility

Although FFP and MBFFP may contain small amounts of red cell stroma, sensitization following the administration of Rh D-positive FFP to Rh D-negative patients is most unlikely as stroma is less immunogenic than intact red cells (Mollison, 1972). The 10th edition of the Council of Europe Guidelines do not require FFP packs to be labelled according to their Rh status (Council of Europe, 2004). 

Recommendation
Fresh-frozen plasma, MBFFP and SDFFP of any Rh type may be given regardless of the Rh status of the recipient. No anti-D prophylaxis is required if Rh D-negative patients receive Rh D-positive FFP (grade B recommendation, level IIa evidence).

5. Dosage

The volume of FFP in each pack is stated on the label and may vary between 180 and 400 ml. The traditional dose of 10–15 ml of plasma per kg body weight may have to be exceeded in massive bleeding (Hellstern & Haubelt, 2002). Therefore, the dose depends on the clinical situation and its monitoring.

6. Thawing and storage of thawed product

Frozen plastic containers are brittle and vulnerable to damage, particularly at the seams and the attached tube remnants, which can be snapped off with ease.

6.1. Thawing of FFP, cryoprecipitate and cryosupernatant

Frozen plasma products must be thawed at 37 C (if thawed at 4 C, cryoprecipitate will form). There are several ways this can be achieved, the most common of which uses a recirculating water bath. This carries a risk of bacterial contamination and must be maintained according to a controlled sterility protocol. Dry heating systems, which avoid denaturing the plasma proteins, are preferred.

6.1.1. Dry ovens (temperature controlled fan-assisted incubator).
These may have a lower potential for contaminating FFP packs with microbes, although they are usually of limited capacity. The time for thawing the FFP is usually 10 min for 2 units.

6.1.2. Microwave ovens. 
Although these defrost in 2–3 min, they have the disadvantage of being expensive and of limited capacity. There are also concerns over the creation of ‘hot spots’ in the packs and the potential for parts of the pack to act as an aerial causing arcing.


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