(e) Once the dose of Factor VIII has been determined, the amount of
product necessary can be calculated easily (see Table 3-2). The duration of treatment
with Factor VIII depends upon the type and location of the hemorrhage and the clinical
response of the patient.
(f) In addition to cryoprecipitated Factor VIII and fresh-frozen plasma,
a number of lyphiIized preparations are available for treatment of Factor VIII deficiency.
These preparations are assayed and labeled for Factor VIII activity, and can be stored
at 4C for extended periods. Since they are made from large plasma pools, they may
carry a higher risk of hepatitis than a comparable amount of Factor VIII administered as
cryoprecipitate.
(2)
Factor lX.
(a) Isolated inherited deficiency of Factor IX is called hemophilia B, and
is clinically similar to hemophilia A. Factor IX Is stable when stored at 4C, or at -20C.
Thus, bank blood, liquid plasma, or fresh-frozen plasma can be used to replace Factor
lX; however, it is difficult to replace large amounts of Factor IX because of the volume of
these products.
(b) Within the past few years, commercial preparations containing
concentrated Factor IX (II, VII, IX, X complex) have become available and can be used
when large amounts of Factor IX must be administered. Disease transmission is a
major risk of transfusion of Factor IX concentrates.
(3)
Fibrinogen.
(a) Hypofibrinogenemia may occur as an isolated inherited deficiency,
or it may be acquired associated with obstetrical complications, disseminated
intravascular coagulation, and some forms of cancer. In acquired hypoflbrinogenemia,
treatment should be directed toward the underlying cause of disease rather than toward
replacement of fibrinogen. Many physicians provide fibrinogen replacement during
correction of the underlying disorder.
(b) Commercial fibrinogen preparations, formerly available, are no
longer manufactured because at the high risk of transmitting hepatitis B.
Cryoprecipitate is used as a source of fibrinogen for replacement therapy. Each bag of
cryoprecipitate from a single donor contains approximately 250 mg of fibrinogen. A
quality assurance program should be established so that this fibrinogen content will be
known in each unit of cryoprecipitate.
MD0846
3-11
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